Foxtail millet(Setaria italica)is an important crop and an emerging model plant.Photoperiodic flowering is a key determinant of its production and geographic expansion.In this study,we found that SiPRR37 is responsibl...Foxtail millet(Setaria italica)is an important crop and an emerging model plant.Photoperiodic flowering is a key determinant of its production and geographic expansion.In this study,we found that SiPRR37 is responsible for the major quantitative trait locus(QTL)Heading date 2(Hd2)identified in 680 foxtail millets using a genome-wide association study.Overexpression of SiPRR37 in foxtail millet significantly delayed the heading date under both natural long-day and short-day conditions.CRISPR/Cas9-induced Siprr37 mutants exhibited earlier flowering in long-day conditions but later flowering in short-day conditions.The critical day length(CDL)for the reversal of Siprr37’s function was around 14.3 h.Haplotype analysis revealed that accessions with the Tc1-Mariner transposon insertion in SiPRR37(Hap 1)flowered significantly earlier at higher latitudes,and later at lower latitudes,indicating that natural variants of SiPRR37 exert dual functions in flowering regulation according to geographic latitude.The gradual,successive decrease in the frequency of Hap 2 from low to high latitudes,with the concurrent increase of Hap 1,demonstrates that these haplotypes have undergone artificial selection.Further FST analysis demonstrated that SiPRR37 has contributed to the ecological adaption of foxtail millet.Additionally,we reveal that OsPRR37 promotes flowering in rice,while GmPRR37 may only inhibit flowering in soybean.Further diurnal expression and transgenic analyses suggest that the dual function of SiPRR37 might depend on SiHd1.Our study uncovered the distinct functional reversal of SiPRR37 and functional diversification of PRR37 homologs in SD crops.These findings not only enrich knowledge about the regulation of photoperiodic flowering,but also contribute to genetic improvement of crops’regional adaptability.展开更多
In seasonally breeding birds, the annual cycle of photoperiod is a principal environmental cue for temporal arrange- ment of different life-history stages, such as migration and breeding. In the past, most research ha...In seasonally breeding birds, the annual cycle of photoperiod is a principal environmental cue for temporal arrange- ment of different life-history stages, such as migration and breeding. In the past, most research has focused on the mechanisms of photoperiodic control of breeding with less attention paid to migration. In Gambel＇s white-crowned sparrow Zonotrichia leuco- phrys gambelii （GWCS）, photoreceptors for induction of breeding are known to reside in the basal hypothalamus. However, it is unknown whether the sites of photoperiodic reception for vernal migration are the same as those for breeding. Therefore, we hy- pothesized that they may be controlled separately. In this study, we exposed photosensitive GWCSs to low-penetration green light （wavelength at 510 nm） under a regime of 1 lux during the day and 〈0.1 lux at night, and switched the photoperiodic conditions from short day （10 h daytime） to long day （18 h daytime）. The results showed that the experimental birds developed traits associ- ated with vernal migration including mass increase, fat deposition and migratory restlessness behavior when transferred from short day to long day green light cycles, while control birds maintained continuously on short day green light conditions did not ex- press any migration related characteristics. Neither experimental nor control groups showed gonadal recrudescence trader either green light cycles. In support of our hypothesis, we were able to apparently dissociate the photoperiodic responses regulating vernal migra- tion and breeding, which suggests separate mechanisms of photoperiodic time measurement. Such distinct photoperiodic mechanisms may drive the free-tuned temporal arrangement of the two life history stages.展开更多
Plants become photosynthetic through de-etiolation, a developmental process regulated by red/far-red light-absorbing phytochromes and blue/ultraviolet A light-absorbing cryptochromes. Genetic screens have identified i...Plants become photosynthetic through de-etiolation, a developmental process regulated by red/far-red light-absorbing phytochromes and blue/ultraviolet A light-absorbing cryptochromes. Genetic screens have identified in the last decade many far-red light signaling mutants and several red and blue light signaling mutants, suggesting the existence of distinct red, far-red, or blue light signaling pathways downstream of phytochromes and cryptochromes. However, genetic screens have also identified mutants with defective de-etiolation responses under multiple wavelengths. Thus, the opti- mal de-etiolation responses of a plant depend on coordination among the different light signaling pathways. This review intends to discuss several recently identified signaling components that have a potential role to integrate red, far-red, and blue light signalings. This review also highlights the recent discoveries on proteolytic degradation in the desensitization of light signal transmission, and the tight connection of light signaling with photoperiodic flowering and circadian rhythm. Studies on the controlling mechanisms of de-etiolation, photoperiodic flowering, and circadian rhythm have been the fascinating topics in Arabidopsis research. The knowledge obtained from Arabidopsis can be readily applied to food crops and ornamental species, and can be contributed to our general understanding of signal perception and transduction in all organisms.展开更多
Floral transition,which is referred to as a plant＇s transition from vegetative stage to reproductive stage,is considered to be a critical developmental switch in higher plants,for a timely flowering is a major factor...Floral transition,which is referred to as a plant＇s transition from vegetative stage to reproductive stage,is considered to be a critical developmental switch in higher plants,for a timely flowering is a major factor of reproductive success.Endogenous and environmental cues,such as photoperiod,light quality,plant hormones concentrations and temperature,provide information to the plants whether the environment is favorable for flowering.These cues promote,or prevent,flowering through a complex genetic network,mediated by a careful orchestration of temporal and spatial gene expression.One of such cues is photoperiod.Rice（Oryza sativa L.） serves as a powerful model species for the understanding of flowering in higher plants,including flower development and photoperiodic control of flowering.In this review,we overviewed and discussed the flower development and its model.We also overviewed the photoperiodic pathways in rice flowering control,and summarized the pathways at molecular level.展开更多
Background: Based on the effect of seasonal changes on human visceral function, this study investigated the impact of seasonal photoperiod of the pineal body on hypothalamic-pituitary-adrenal axis-hippocampal-receptor...Background: Based on the effect of seasonal changes on human visceral function, this study investigated the impact of seasonal photoperiod of the pineal body on hypothalamic-pituitary-adrenal axis-hippocampal-receptor in rats, aiming to reveal the mechanism by which pineal gland melatonin regulates the seasonal secretion of hippocampal neurotransmitters.Methods: Vernal equinox, summer solstice, autumn equinox, and winter solstice were selected as four experimental time points, and rats were randomly divided into normal control group, sham operation group, and pinealectomized group. The seasonal changes in corticotropin-releasing hormone(CRH),adrenocorticotropic hormone(ACTH), corticosterone, hypothalamic melatonin receptor(MTR), and hippocampal corticosterone receptor(CORTR) were examined by enzyme-linked immunosorbent assay.Results: Comparing the same group between different seasons, we showed that in the normal control group, CRH, ACTH, corticosterone, and MTR were higher, while CORTR was lower in autumn and winter than in spring(all P <.05). Compared with the normal control group, the pinealectomized group showed higher levels of corticosterone(P =.01), MTR(P =.01), and CORTR(P =.03) during spring;reduced levels of MTR and CORTR(both P <.001) during summer;higher levels of ACTH(P =.001) and MTR(P <.001),and lower levels of CRH(P =.001), corticosterone(P <.001), and CORTR(P =.003) during autumn;and lower levels of CRH(P <.001) and MTR(P =.004), and higher level of ACTH(P <.001) in winter.Conclusions: Seasonal photoperiod acts on the pineal gland to secrete different levels of melatonin,resulting in seasonal changes in the hypothalamic-pituitary-adrenal axis-hippocampal-receptor, which may be the pathophysiological basis for the onset of seasonal affective disorder.展开更多
Environmental sensitivity varies across developmental phases in flowering plants. In the juvenile phase, mi- croRNA156 （miR156）-mediated repression of SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE （SPL） transcription fac...Environmental sensitivity varies across developmental phases in flowering plants. In the juvenile phase, mi- croRNA156 （miR156）-mediated repression of SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE （SPL） transcription factors renders Arabidopsis plants incompetent to floral inductive signals, including long- day （LD） photoperiod. During the vegetative phase transition, which accompanies a reduction of miR156 and a concomitant elevation of its targets, plants acquire reproductive competence such that LD signals promote flowering. However, it remains largely unknown how developmental signals are associated with photoperiodic flowering. Here, we show that SPL3, SPL4, and SPL5 （SPL3/4/5） potentiate the FLOWERING LOCUS T （FT）-FD module in photoperiodic flowering. SPL3/4/5 function as transcriptional activators through the interaction with FD, a basic leucine zipper transcription factor which plays a critical role in photoperiodic flowering. SPL3/4/5 can directly bind to the promoters of APETALA1, LEAFY, and FRUITFULL, thus mediating their activation by the FT-FD complex. Our findings demonstrate that SPL3/ 4/5 act synergistically with the FT-FD module to induce flowering under LDs, providing a long-sought mo- lecular knob that links developmental aging and photoperiodic flowering.展开更多
Photoperiodic flowering is one of the most important factors affecting regional adaptation and yield in soybean(Glycine max). Plant adaptation to long-day conditions at higher latitudes requires early flowering and a ...Photoperiodic flowering is one of the most important factors affecting regional adaptation and yield in soybean(Glycine max). Plant adaptation to long-day conditions at higher latitudes requires early flowering and a reduction or loss of photoperiod sensitivity;adaptation to short-day conditions at lower latitudes involves delayed flowering, which prolongs vegetative growth for maximum yield potential. Due to the influence of numerous major loci and quantitative trait loci(QTLs), soybean has broad adaptability across latitudes. Forward genetic approaches have uncovered the molecular basis for several of these major maturity genes and QTLs. Moreover, the molecular characterization of orthologs of Arabidopsis thaliana flowering genes has enriched our understanding of the photoperiodic flowering pathway in soybean. Building on early insights into the importance of the photoreceptor phytochrome A, several circadian clock components have been integrated into the genetic network controlling flowering in soybean: E1, a repressor of FLOWERING LOCUS T orthologs, plays a central role in this network. Here, we provide an overview of recent progress in elucidating photoperiodic flowering in soybean, how it contributes to our fundamental understanding of flowering time control, and how this information could be used for molecular design and breeding of high-yielding soybean cultivars.展开更多
Flowering links vegetative growth and reproductive growth and involves the coordination of local environmental cues and plant genetic information.Appropriate timing of floral initiation and maturation in both wild and...Flowering links vegetative growth and reproductive growth and involves the coordination of local environmental cues and plant genetic information.Appropriate timing of floral initiation and maturation in both wild and cultivated plants is important to their fitness and productivity in a given growth environment.The domestication of plants into crops,and later crop expansion and improvement,has often involved selection for early flowering.In this review,we analyze the basic rules for photoperiodic adaptation in several economically important and/or well-researched crop species.The ancestors of rice(Oryza sativa),maize(Zea mays),soybean(Glycine max),and tomato(Solanum lycopersicum)are short-day plants whose photosensitivity was reduced or lost during domestication and expansion to high-latitude areas.Wheat(Triticum aestivum)and barley(Hordeum vulgare)are long-day crops whose photosensitivity is influenced by both latitude and vernalization type.Here,we summarize recent studies about where these crops were domesticated,how they adapted to photoperiodic conditions as their growing area expanded from domestication locations to modern cultivating regions,and how allelic variants of photoperiodic flowering genes were selected during this process.A deeper understanding of photoperiodic flowering in each crop will enable better molecular design and breeding of high-yielding cultivars suited to particular local environments.展开更多
The timing of flowering affects the success of sexual reproduction.This developmental event also determines crop yield,biomass,and longevity.Therefore,this mechanism has been targeted for improvement along with crop d...The timing of flowering affects the success of sexual reproduction.This developmental event also determines crop yield,biomass,and longevity.Therefore,this mechanism has been targeted for improvement along with crop domestication.The underlying mechanisms of flowering are highly conserved in angiosperms.Central to these mechanisms is how environmental and endogenous conditions control transcriptional regulation of the FLOWERING LOCUS T(FT)gene,which initiates floral development under long-day conditions in Arabidopsis.Since the identification of FT as florigen,efforts have been made to understand the regulatory mechanisms of FT expression.Although many transcriptional regulators have been shown to directly influence FT,the question of how they coordinately control the spatiotemporal expression patterns of FT still requires further investigation.Among FT regulators,CONSTANS(CO)is the primary one whose protein stability is tightly controlled by phosphorylation and ubiquitination/proteasome-mediated mechanisms.In addition,various CO interaction partners,some of them previously identified as FT transcriptional regulators,positively or negatively modulate CO protein activity.The FT promoter possesses several transcriptional regulatory"blocks,"highly conserved regions among Brassicaceae plants.Different transcription factors bind to specific blocks and affect FT expression,often causing topological changes in FT chromatin structure,such as the formation of DNA loops.We discuss the current understanding of the regulation of FT expression mainly in Arabidopsis and propose future directions related to this topic.展开更多
Background:Aedes albopictus is among the 100 most invasive species worldwide and poses a major risk to public health.Photoperiodic diapause provides a crucial ecological basis for the adaptation of this species to adv...Background:Aedes albopictus is among the 100 most invasive species worldwide and poses a major risk to public health.Photoperiodic diapause provides a crucial ecological basis for the adaptation of this species to adverse environments.Ae.albopictus is the vital vector transmitting dengue virus in Guangzhou,but its diapause activities herein remain obscure.Methods:In the laboratory,yeast powder and food slurry were compared for a proper diapause determination method,and the critical photoperiod(CPP)was tested at illumination times of 11,11.5,12,12.5,13,and 13.5 h.A 4-parameter logistic(4PL)regression model was selected to estimate the CPP.In the field,the seasonal dynamics of the Ae.albopictus population,egg diapause,and hatching of overwintering eggs were investigated monthly,weekly,and daily,respectively.A distributed lag non-linear model(DLNM)was used to assess the associations of diapause with meteorological factors.Results:In the laboratory,both the wild population and the Foshan strain of Ae.albopictus were induced to diapause at an incidence greater than 80%,and no significant difference(P>0.1)was observed between the two methods for identifying diapause.The CPP of this population was estimated to be 12.312 h of light.In the field,all of the indexes of the wild population were at the lowest levels from December to February,and the Route Index was the first to increase in March.Diapause incidence displayed pronounced seasonal dynamics.It was estimated that the day lengths of 12.111 h at week2016,43 and 12.373 h at week2017,41 contributed to diapause in 50%of the eggs.Day length was estimated to be the main meteorological factor related to diapause.Conclusions:Photoperiodic diapause of Ae.albopictus in Guangzhou of China was confirmed and comprehensively elucidated in both the laboratory and the field.Diapause eggs are the main form for overwintering and begin to hatch in large quantities in March in Guangzhou.Furthermore,this study also established an optimized investigation system and statistical models for the study of Ae.albopictus diapause.These findings will contribute to the prevention and control of Ae.albopictus and mosquito-borne diseases.展开更多
Flowering symbolizes the transition of s plant from vegetative phase to reproductive phase and is controlled by fairly complex and highly coordinated regulatory pathways. Over the last decade, genetic studies in Arabi...Flowering symbolizes the transition of s plant from vegetative phase to reproductive phase and is controlled by fairly complex and highly coordinated regulatory pathways. Over the last decade, genetic studies in Arabidopsis have aided the discovery of many signaling components involved in these pathways. In this review, we discuss how the timing of flowering is regulated by photoperiod and the involvement of light perception and the circadian clock in this process. The specific regulatory mechanisms on CONSTANS expression and CONSTANS stability by the circadian clock and photoreceptors are described in detail. In addition, the roles of CONSTANS, FLOWERING LOCUS T, and several other light signaling and circadian-dependent components in photoperiodic flowering are also highlighted.展开更多
In our experiment, three groups of seedlings of SDP Pharbitis nil cv. violet were sepa-rately treated with three different photoperiods (1,16 h dark period--SD; 2, continuous illumi-nation--CL; 3, 16 h dark treatment ...In our experiment, three groups of seedlings of SDP Pharbitis nil cv. violet were sepa-rately treated with three different photoperiods (1,16 h dark period--SD; 2, continuous illumi-nation--CL; 3, 16 h dark treatment with 10 min white light in the middle of the dark period--NB). By analysing proteins in the cotyledons from three groups with 2-D PAGE, we found nodifference in protein pattern between the three groups at 0 or 8 h after photoperiodic treatments.At 24 h after the treatments, a specific protein(MW:19 kD; pI: 4.5)appeared only in the cotyledonsof the seedlings which endured SD. This protein disappeared at 72 h after SD. ActinomycinD could inhibit flowering and the specific protein occurrence when applied to cotyledonsprior to SD, but it had no inhibition effect on flowering as well as the specific proteinoccurrence when applied to cotyledons after SD. Chloroamphenicol, a protein synthesisinhibitor, inhibited flowering when applied to cotyledons prior to or immediately after SD,but it did not inhibit flowering when applied to cotyledons at 24 h after SD. With the jointconsideration of the effects of defoliation and inhibitor applications on flowering, wededuced that the 19 kD protein occurrence correlated with the commitment to flowering. Thegene transcription related with induction was fulfilled within the SD period, while thespecific protein synthesis lasted 24 h after SD. The key regulation step of biochemical changesduring induction was at the transcriptional level.展开更多
Due to the risk of extinction and ornamental value of the swallowtail butterfly, Sericinus montelus Gray （Lepidoptera： Papilionidae） in China, knowledge about local adaptations is important for the conservation and...Due to the risk of extinction and ornamental value of the swallowtail butterfly, Sericinus montelus Gray （Lepidoptera： Papilionidae） in China, knowledge about local adaptations is important for the conservation and economical utilization of the species. In the present study, photoperiodie diapause induction and diapause intensity of S. montelus populations from Jiamusi （46°37＇N）, Beijing （40° 15＇N）, Zibo （36°48＇N）, Fangxian （32°36＇N）, Wuhan （30°33＇N） and Huaihua （27°33＇N） were characterized at 25℃. Logistic regression analysis revealed a significant population x hours of light interaction, confirming that photoperiodic responses varied among populations. The critical photoperiod was positively correlated with latitude and increased toward the north at a rate of about 1 h for each 6.67 degrees of latitude. Survival analyses indicated that survival time of diapausing pupae before adult eclosion differed significantly among populations at 25℃ and 16 ： 8 L ＂D h. The mean duration of pupal diapause was also positively correlated with latitude. Our study reveals geographic variation in the critical photoperiod for diapause induction and in diapause intensity of S. montelus. These results provide useful information for our general understanding about seasonal adaptation in insects and may also be used to predict how geographic populations respond to climate warming.展开更多
Glycine max is a photoperiodic short-day plant and the practical consequence of the response is latitude and sowing period limitations to commercial crops. Genetic and physiological studies using the model plants Arab...Glycine max is a photoperiodic short-day plant and the practical consequence of the response is latitude and sowing period limitations to commercial crops. Genetic and physiological studies using the model plants Arabidopsis thaliana and rice （Oryza sativa） have uncovered several genes and genetic pathways controlling the process, however information about the corresponding pathways in legumes is scarce. Data mining prediction methodologies, including multiple sequence alignment, phylogeneUc analysis, bioinformaUcs expression and sequence motif pattern identification, were used to identify soybean genes involved in day length perception and photoperiodic flowering induction. We have investigated approximately 330 000 sequences from open-access databases and have identified all bona fide central oscillator genes and circadian photoreceptors from A. thaliana in soybean sequence databases. We propose a working model for the photoperiodic control of flowering time in G. max, based on the identified key components. These results demonstrate the power of comparative genomics between model systems and crop species to elucidate the several aspects of plant physiology and metabolism.展开更多
Circadian clocks synchronize internal physiological responses to occur at the most optimal time of the day.In plants,hormone signaling is under the control of this clock.It has been previously shown that the circadian...Circadian clocks synchronize internal physiological responses to occur at the most optimal time of the day.In plants,hormone signaling is under the control of this clock.It has been previously shown that the circadian clock moderates the plant’s sensitivity to gibberellin(GA)by regulating the expression of GA receptors.Recently,two papers by Nohales and Kay(2019)and Park et al.(2020)revealed that post-translational regulation of DELLA proteins by the circadian clock also contributes to timing when the plant is most sensitive to GA.展开更多
In this artice Figs.2 and 3 were wrongly numbered;Fig.2 should have been Fig.3 and vice versa as shown below.Moreover,the Fig.3 indications have been revised as shown:the sentence"Next,two transfer DNA(T-DNA)inse...In this artice Figs.2 and 3 were wrongly numbered;Fig.2 should have been Fig.3 and vice versa as shown below.Moreover,the Fig.3 indications have been revised as shown:the sentence"Next,two transfer DNA(T-DNA)insertion single-mutant prmt6-1(Sail 385_A06)and prmt6-2(Salk 151679C)(Figs.2A;S3)..'has been revised as“Next,two transfer DNA(T-DNA)inser-tion single-mutant prmt6-1(Sail 385_A06)and prmt6-2(Salk 151679C)(Figs.3A;S3..".展开更多
A later heading date generally leads to higher grain yield in favorable ecological regions;however,grain yield reaches a limit as the heading date exceeds a certain threshold.Ghd7 is the first cloned major gene that r...A later heading date generally leads to higher grain yield in favorable ecological regions;however,grain yield reaches a limit as the heading date exceeds a certain threshold.Ghd7 is the first cloned major gene that regulates heading date,plant height and grain number.Here,we investigated the relationship between Ghd7 and florigen genes Hd3a and RFT1,to determine their roles in regulating heading date and grain number under different photoperiods.Our results revealed that under long-day(LD)conditions,Hd3a acts prior to RFT1 to promote heading while negatively regulating plant height and grain number.In contrast,Ghd7 positively regulates heading date,plant height,and grain number by inhibiting both Hd3a and RFT1.Under short-day(SD)conditions,the functions of Hd3a and RFT1 remain consistent with those under LD conditions,but Ghd7 does not inhibit their expression,resulting in a weaker phenotypic effect compared to Hd3a.Additionally,under both LD and SD conditions,increased Ghd7 expression enhances its inhibitory effect on Hd3a and RFT1,leading to later heading and increased grain number;however,once the heading date exceeds 94 d,grain number no longer increases.Moreover,the gn1a allele increased grain number by 16.5%to 42.5%,while combinations of the elite alleles from Ghd7,Hd3a,RFT1,and Gn1a significantly increased grain number by up to 240.9%.Therefore,we propose a new breeding strategy to optimize the heading date and grain number using the Ghd7Hd3aRFT1gn1a combination of Ghd7,Hd3a,RFT1,and Gn1a under LD conditions,and the Ghd7hd3aRFT1gn1a combination under SD conditions.This strategy improved the yield of the high-quality Northeast variety Kongyu 131(KY131)by 69.1%in Beijing and 93.7%in Hainan.This strategy will greatly improve the efficiency of north-to-south adaptation in rice,providing theoretical guidance for expanding the geographical adaptability of rice varieties.展开更多
Climate warming is reshaping the phenology of plants in recent decades,with potential implications for forest productivity,carbon sequestration,and ecosystem functioning.While the effects of warming on secondary growt...Climate warming is reshaping the phenology of plants in recent decades,with potential implications for forest productivity,carbon sequestration,and ecosystem functioning.While the effects of warming on secondary growth phenology is becoming increasingly clear,the influenceof environmental factors on different developmental phases of xylem remains to be quantified.In this study,we investigated the temporal dynamics of xylem cell enlargement,wall-thickening,and the interval between these events in twelve temperate tree species from Northeast China over the period 2019–2024.We found that both cell enlargement and wall-thickening advanced significantlyin response to climate warming,with species-specific variations in the rate of advancement.Importantly,the advancing rate of wallthickening was greater than that of cell enlargement,leading to a shortening of the interval between these two events.Linear mixed-effects models revealed that photoperiod,forcing temperature,and precipitation were the primary environmental drivers influencingthe timing of both cell enlargement and wall-thickening,with photoperiod emerging as the most important factor.These results suggest that climate warming accelerates the heat accumulation required for the transition from xylem cell enlargement to wall-thickening,thereby shortening the time interval between these two developmental stages.Beyond contributing valuable multi-year xylem phenological data,our results provide mechanistic insights that enhance predictions of wood formation dynamics under future climate scenarios and improve the accuracy of forest carbon models.展开更多
Photoperiod and temperature are crucial factors that trigger flowering in Brassica juncea(B.juncea).However,the underlying regulatory mechanisms remain poorly understood.The MADS-box transcription factor AGL18 acts as...Photoperiod and temperature are crucial factors that trigger flowering in Brassica juncea(B.juncea).However,the underlying regulatory mechanisms remain poorly understood.The MADS-box transcription factor AGL18 acts as a pivotal repressor of floral transition and functions redundantly with AGL15.In this study,we isolated BjuAGL18-1 from B.juncea and identified two unique transcripts,resulting in two distinct proteins:a full-length protein,BjuAGL18-1L,and a truncated protein,BjuAGL18-1S.Further investigation showed that the two isoforms had similar subcellular localizations but different expression patterns in various plant tissues.Notably,BjuAGL18-1L and BjuAGL18-1S were abundantly induced under short-and long-day photoperiods,respectively.BjuAGL18-1L overexpression in B.juncea and Arabidopsis thaliana(A.thaliana)led to late flowering,whereas BjuAGL18-1S overexpression resulted in early flowering.Yeast two-hybrid,bimolecular fluorescent complementation,and luciferase complementation assays showed that BjuAGL18-1L,but not BjuAGL18-1S(which lacked the EAR motif),interacted with the co-repressor BjuAFR2 and the histone deacetylase BjuHDA9 to form a multiprotein complex.Further analysis indicated that BjuAGL18-1L could also form a complex with BjuAGL15 and bind to the BjuFUL promoter,thus inhibiting its expression.However,BjuAGL18-1S interacted with BjuAGL18-1L to form heterodimers,which attenuated their activities,likely by disrupting their binding to target genes,resulting in accelerated flowering progression.These results suggest that BjuAGL18-1 is involved in photoperiod-induced flowering via different regulatory mechanisms in B.juncea.展开更多
基金supported by the National Natural Science Foundation of China(32101759,32241042)the National Key Research and Development Program of China(2023YFD1200700 and 2023YFD1200704).
文摘Foxtail millet(Setaria italica)is an important crop and an emerging model plant.Photoperiodic flowering is a key determinant of its production and geographic expansion.In this study,we found that SiPRR37 is responsible for the major quantitative trait locus(QTL)Heading date 2(Hd2)identified in 680 foxtail millets using a genome-wide association study.Overexpression of SiPRR37 in foxtail millet significantly delayed the heading date under both natural long-day and short-day conditions.CRISPR/Cas9-induced Siprr37 mutants exhibited earlier flowering in long-day conditions but later flowering in short-day conditions.The critical day length(CDL)for the reversal of Siprr37’s function was around 14.3 h.Haplotype analysis revealed that accessions with the Tc1-Mariner transposon insertion in SiPRR37(Hap 1)flowered significantly earlier at higher latitudes,and later at lower latitudes,indicating that natural variants of SiPRR37 exert dual functions in flowering regulation according to geographic latitude.The gradual,successive decrease in the frequency of Hap 2 from low to high latitudes,with the concurrent increase of Hap 1,demonstrates that these haplotypes have undergone artificial selection.Further FST analysis demonstrated that SiPRR37 has contributed to the ecological adaption of foxtail millet.Additionally,we reveal that OsPRR37 promotes flowering in rice,while GmPRR37 may only inhibit flowering in soybean.Further diurnal expression and transgenic analyses suggest that the dual function of SiPRR37 might depend on SiHd1.Our study uncovered the distinct functional reversal of SiPRR37 and functional diversification of PRR37 homologs in SD crops.These findings not only enrich knowledge about the regulation of photoperiodic flowering,but also contribute to genetic improvement of crops’regional adaptability.
文摘In seasonally breeding birds, the annual cycle of photoperiod is a principal environmental cue for temporal arrange- ment of different life-history stages, such as migration and breeding. In the past, most research has focused on the mechanisms of photoperiodic control of breeding with less attention paid to migration. In Gambel＇s white-crowned sparrow Zonotrichia leuco- phrys gambelii （GWCS）, photoreceptors for induction of breeding are known to reside in the basal hypothalamus. However, it is unknown whether the sites of photoperiodic reception for vernal migration are the same as those for breeding. Therefore, we hy- pothesized that they may be controlled separately. In this study, we exposed photosensitive GWCSs to low-penetration green light （wavelength at 510 nm） under a regime of 1 lux during the day and 〈0.1 lux at night, and switched the photoperiodic conditions from short day （10 h daytime） to long day （18 h daytime）. The results showed that the experimental birds developed traits associ- ated with vernal migration including mass increase, fat deposition and migratory restlessness behavior when transferred from short day to long day green light cycles, while control birds maintained continuously on short day green light conditions did not ex- press any migration related characteristics. Neither experimental nor control groups showed gonadal recrudescence trader either green light cycles. In support of our hypothesis, we were able to apparently dissociate the photoperiodic responses regulating vernal migra- tion and breeding, which suggests separate mechanisms of photoperiodic time measurement. Such distinct photoperiodic mechanisms may drive the free-tuned temporal arrangement of the two life history stages.
文摘Plants become photosynthetic through de-etiolation, a developmental process regulated by red/far-red light-absorbing phytochromes and blue/ultraviolet A light-absorbing cryptochromes. Genetic screens have identified in the last decade many far-red light signaling mutants and several red and blue light signaling mutants, suggesting the existence of distinct red, far-red, or blue light signaling pathways downstream of phytochromes and cryptochromes. However, genetic screens have also identified mutants with defective de-etiolation responses under multiple wavelengths. Thus, the opti- mal de-etiolation responses of a plant depend on coordination among the different light signaling pathways. This review intends to discuss several recently identified signaling components that have a potential role to integrate red, far-red, and blue light signalings. This review also highlights the recent discoveries on proteolytic degradation in the desensitization of light signal transmission, and the tight connection of light signaling with photoperiodic flowering and circadian rhythm. Studies on the controlling mechanisms of de-etiolation, photoperiodic flowering, and circadian rhythm have been the fascinating topics in Arabidopsis research. The knowledge obtained from Arabidopsis can be readily applied to food crops and ornamental species, and can be contributed to our general understanding of signal perception and transduction in all organisms.
基金funded by the National High Technology Research and Development Program fromthe Ministry of Science and Technology of China(Grant No. 2010AA101806)the Bill & Melinda Gates Foundation (Grant No. OPP51587)
文摘Floral transition,which is referred to as a plant＇s transition from vegetative stage to reproductive stage,is considered to be a critical developmental switch in higher plants,for a timely flowering is a major factor of reproductive success.Endogenous and environmental cues,such as photoperiod,light quality,plant hormones concentrations and temperature,provide information to the plants whether the environment is favorable for flowering.These cues promote,or prevent,flowering through a complex genetic network,mediated by a careful orchestration of temporal and spatial gene expression.One of such cues is photoperiod.Rice（Oryza sativa L.） serves as a powerful model species for the understanding of flowering in higher plants,including flower development and photoperiodic control of flowering.In this review,we overviewed and discussed the flower development and its model.We also overviewed the photoperiodic pathways in rice flowering control,and summarized the pathways at molecular level.
基金supported by the National Natural Science Foundation of China (81774162)
文摘Background: Based on the effect of seasonal changes on human visceral function, this study investigated the impact of seasonal photoperiod of the pineal body on hypothalamic-pituitary-adrenal axis-hippocampal-receptor in rats, aiming to reveal the mechanism by which pineal gland melatonin regulates the seasonal secretion of hippocampal neurotransmitters.Methods: Vernal equinox, summer solstice, autumn equinox, and winter solstice were selected as four experimental time points, and rats were randomly divided into normal control group, sham operation group, and pinealectomized group. The seasonal changes in corticotropin-releasing hormone(CRH),adrenocorticotropic hormone(ACTH), corticosterone, hypothalamic melatonin receptor(MTR), and hippocampal corticosterone receptor(CORTR) were examined by enzyme-linked immunosorbent assay.Results: Comparing the same group between different seasons, we showed that in the normal control group, CRH, ACTH, corticosterone, and MTR were higher, while CORTR was lower in autumn and winter than in spring(all P <.05). Compared with the normal control group, the pinealectomized group showed higher levels of corticosterone(P =.01), MTR(P =.01), and CORTR(P =.03) during spring;reduced levels of MTR and CORTR(both P <.001) during summer;higher levels of ACTH(P =.001) and MTR(P <.001),and lower levels of CRH(P =.001), corticosterone(P <.001), and CORTR(P =.003) during autumn;and lower levels of CRH(P <.001) and MTR(P =.004), and higher level of ACTH(P <.001) in winter.Conclusions: Seasonal photoperiod acts on the pineal gland to secrete different levels of melatonin,resulting in seasonal changes in the hypothalamic-pituitary-adrenal axis-hippocampal-receptor, which may be the pathophysiological basis for the onset of seasonal affective disorder.
文摘Environmental sensitivity varies across developmental phases in flowering plants. In the juvenile phase, mi- croRNA156 （miR156）-mediated repression of SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE （SPL） transcription factors renders Arabidopsis plants incompetent to floral inductive signals, including long- day （LD） photoperiod. During the vegetative phase transition, which accompanies a reduction of miR156 and a concomitant elevation of its targets, plants acquire reproductive competence such that LD signals promote flowering. However, it remains largely unknown how developmental signals are associated with photoperiodic flowering. Here, we show that SPL3, SPL4, and SPL5 （SPL3/4/5） potentiate the FLOWERING LOCUS T （FT）-FD module in photoperiodic flowering. SPL3/4/5 function as transcriptional activators through the interaction with FD, a basic leucine zipper transcription factor which plays a critical role in photoperiodic flowering. SPL3/4/5 can directly bind to the promoters of APETALA1, LEAFY, and FRUITFULL, thus mediating their activation by the FT-FD complex. Our findings demonstrate that SPL3/ 4/5 act synergistically with the FT-FD module to induce flowering under LDs, providing a long-sought mo- lecular knob that links developmental aging and photoperiodic flowering.
基金supported by grants from the National Natural Science Foundation of China(31725021)to F.K.and(31930083)B.L.the State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources(SKLCUSA-b201803)to X.L.
文摘Photoperiodic flowering is one of the most important factors affecting regional adaptation and yield in soybean(Glycine max). Plant adaptation to long-day conditions at higher latitudes requires early flowering and a reduction or loss of photoperiod sensitivity;adaptation to short-day conditions at lower latitudes involves delayed flowering, which prolongs vegetative growth for maximum yield potential. Due to the influence of numerous major loci and quantitative trait loci(QTLs), soybean has broad adaptability across latitudes. Forward genetic approaches have uncovered the molecular basis for several of these major maturity genes and QTLs. Moreover, the molecular characterization of orthologs of Arabidopsis thaliana flowering genes has enriched our understanding of the photoperiodic flowering pathway in soybean. Building on early insights into the importance of the photoreceptor phytochrome A, several circadian clock components have been integrated into the genetic network controlling flowering in soybean: E1, a repressor of FLOWERING LOCUS T orthologs, plays a central role in this network. Here, we provide an overview of recent progress in elucidating photoperiodic flowering in soybean, how it contributes to our fundamental understanding of flowering time control, and how this information could be used for molecular design and breeding of high-yielding soybean cultivars.
基金by Grants from the National Natural Science Foundation of China to F.K.(32090064)and to X.L.(32001568)supported by the Major Program of Guangdong Basic and Applied Research to F.K.(2019B030302006).
文摘Flowering links vegetative growth and reproductive growth and involves the coordination of local environmental cues and plant genetic information.Appropriate timing of floral initiation and maturation in both wild and cultivated plants is important to their fitness and productivity in a given growth environment.The domestication of plants into crops,and later crop expansion and improvement,has often involved selection for early flowering.In this review,we analyze the basic rules for photoperiodic adaptation in several economically important and/or well-researched crop species.The ancestors of rice(Oryza sativa),maize(Zea mays),soybean(Glycine max),and tomato(Solanum lycopersicum)are short-day plants whose photosensitivity was reduced or lost during domestication and expansion to high-latitude areas.Wheat(Triticum aestivum)and barley(Hordeum vulgare)are long-day crops whose photosensitivity is influenced by both latitude and vernalization type.Here,we summarize recent studies about where these crops were domesticated,how they adapted to photoperiodic conditions as their growing area expanded from domestication locations to modern cultivating regions,and how allelic variants of photoperiodic flowering genes were selected during this process.A deeper understanding of photoperiodic flowering in each crop will enable better molecular design and breeding of high-yielding cultivars suited to particular local environments.
基金supported by grants from the National Institutes of Health(R01GM079712)MEXT KAKENHI grants(20H05910 and 22H04978).
文摘The timing of flowering affects the success of sexual reproduction.This developmental event also determines crop yield,biomass,and longevity.Therefore,this mechanism has been targeted for improvement along with crop domestication.The underlying mechanisms of flowering are highly conserved in angiosperms.Central to these mechanisms is how environmental and endogenous conditions control transcriptional regulation of the FLOWERING LOCUS T(FT)gene,which initiates floral development under long-day conditions in Arabidopsis.Since the identification of FT as florigen,efforts have been made to understand the regulatory mechanisms of FT expression.Although many transcriptional regulators have been shown to directly influence FT,the question of how they coordinately control the spatiotemporal expression patterns of FT still requires further investigation.Among FT regulators,CONSTANS(CO)is the primary one whose protein stability is tightly controlled by phosphorylation and ubiquitination/proteasome-mediated mechanisms.In addition,various CO interaction partners,some of them previously identified as FT transcriptional regulators,positively or negatively modulate CO protein activity.The FT promoter possesses several transcriptional regulatory"blocks,"highly conserved regions among Brassicaceae plants.Different transcription factors bind to specific blocks and affect FT expression,often causing topological changes in FT chromatin structure,such as the formation of DNA loops.We discuss the current understanding of the regulation of FT expression mainly in Arabidopsis and propose future directions related to this topic.
基金This study was supported by the National Key Research and Development Program of China(2016YFC1200500)the Guangzhou Synergy Innovation Key Program for Health(201508020263)+1 种基金the Science and Technology Planning Project of Guangdong Province of China(2016A020251001)the Guangzhou International Science and Technology Cooperation Program(2012 J5100026).
文摘Background:Aedes albopictus is among the 100 most invasive species worldwide and poses a major risk to public health.Photoperiodic diapause provides a crucial ecological basis for the adaptation of this species to adverse environments.Ae.albopictus is the vital vector transmitting dengue virus in Guangzhou,but its diapause activities herein remain obscure.Methods:In the laboratory,yeast powder and food slurry were compared for a proper diapause determination method,and the critical photoperiod(CPP)was tested at illumination times of 11,11.5,12,12.5,13,and 13.5 h.A 4-parameter logistic(4PL)regression model was selected to estimate the CPP.In the field,the seasonal dynamics of the Ae.albopictus population,egg diapause,and hatching of overwintering eggs were investigated monthly,weekly,and daily,respectively.A distributed lag non-linear model(DLNM)was used to assess the associations of diapause with meteorological factors.Results:In the laboratory,both the wild population and the Foshan strain of Ae.albopictus were induced to diapause at an incidence greater than 80%,and no significant difference(P>0.1)was observed between the two methods for identifying diapause.The CPP of this population was estimated to be 12.312 h of light.In the field,all of the indexes of the wild population were at the lowest levels from December to February,and the Route Index was the first to increase in March.Diapause incidence displayed pronounced seasonal dynamics.It was estimated that the day lengths of 12.111 h at week2016,43 and 12.373 h at week2017,41 contributed to diapause in 50%of the eggs.Day length was estimated to be the main meteorological factor related to diapause.Conclusions:Photoperiodic diapause of Ae.albopictus in Guangzhou of China was confirmed and comprehensively elucidated in both the laboratory and the field.Diapause eggs are the main form for overwintering and begin to hatch in large quantities in March in Guangzhou.Furthermore,this study also established an optimized investigation system and statistical models for the study of Ae.albopictus diapause.These findings will contribute to the prevention and control of Ae.albopictus and mosquito-borne diseases.
基金Supported by the National Research Initiative of the USDA Cooperative State Research, Education and Extension Service Fund （2004-35304-14939） and Hatch Fund. Publication of this paper is supported by the National Natural Science Foundation of China （30624808） and Science Publication Foundation of the Chinese Academy of Sciences.Acknowledgements We apologize to the author whose work we were unable to cite or discuss due to the topic and length limitations. We thank Ali Sivitz at University of Minnesota for critical reading of the manuscript.
文摘Flowering symbolizes the transition of s plant from vegetative phase to reproductive phase and is controlled by fairly complex and highly coordinated regulatory pathways. Over the last decade, genetic studies in Arabidopsis have aided the discovery of many signaling components involved in these pathways. In this review, we discuss how the timing of flowering is regulated by photoperiod and the involvement of light perception and the circadian clock in this process. The specific regulatory mechanisms on CONSTANS expression and CONSTANS stability by the circadian clock and photoreceptors are described in detail. In addition, the roles of CONSTANS, FLOWERING LOCUS T, and several other light signaling and circadian-dependent components in photoperiodic flowering are also highlighted.
文摘In our experiment, three groups of seedlings of SDP Pharbitis nil cv. violet were sepa-rately treated with three different photoperiods (1,16 h dark period--SD; 2, continuous illumi-nation--CL; 3, 16 h dark treatment with 10 min white light in the middle of the dark period--NB). By analysing proteins in the cotyledons from three groups with 2-D PAGE, we found nodifference in protein pattern between the three groups at 0 or 8 h after photoperiodic treatments.At 24 h after the treatments, a specific protein(MW:19 kD; pI: 4.5)appeared only in the cotyledonsof the seedlings which endured SD. This protein disappeared at 72 h after SD. ActinomycinD could inhibit flowering and the specific protein occurrence when applied to cotyledonsprior to SD, but it had no inhibition effect on flowering as well as the specific proteinoccurrence when applied to cotyledons after SD. Chloroamphenicol, a protein synthesisinhibitor, inhibited flowering when applied to cotyledons prior to or immediately after SD,but it did not inhibit flowering when applied to cotyledons at 24 h after SD. With the jointconsideration of the effects of defoliation and inhibitor applications on flowering, wededuced that the 19 kD protein occurrence correlated with the commitment to flowering. Thegene transcription related with induction was fulfilled within the SD period, while thespecific protein synthesis lasted 24 h after SD. The key regulation step of biochemical changesduring induction was at the transcriptional level.
文摘Due to the risk of extinction and ornamental value of the swallowtail butterfly, Sericinus montelus Gray （Lepidoptera： Papilionidae） in China, knowledge about local adaptations is important for the conservation and economical utilization of the species. In the present study, photoperiodie diapause induction and diapause intensity of S. montelus populations from Jiamusi （46°37＇N）, Beijing （40° 15＇N）, Zibo （36°48＇N）, Fangxian （32°36＇N）, Wuhan （30°33＇N） and Huaihua （27°33＇N） were characterized at 25℃. Logistic regression analysis revealed a significant population x hours of light interaction, confirming that photoperiodic responses varied among populations. The critical photoperiod was positively correlated with latitude and increased toward the north at a rate of about 1 h for each 6.67 degrees of latitude. Survival analyses indicated that survival time of diapausing pupae before adult eclosion differed significantly among populations at 25℃ and 16 ： 8 L ＂D h. The mean duration of pupal diapause was also positively correlated with latitude. Our study reveals geographic variation in the critical photoperiod for diapause induction and in diapause intensity of S. montelus. These results provide useful information for our general understanding about seasonal adaptation in insects and may also be used to predict how geographic populations respond to climate warming.
文摘Glycine max is a photoperiodic short-day plant and the practical consequence of the response is latitude and sowing period limitations to commercial crops. Genetic and physiological studies using the model plants Arabidopsis thaliana and rice （Oryza sativa） have uncovered several genes and genetic pathways controlling the process, however information about the corresponding pathways in legumes is scarce. Data mining prediction methodologies, including multiple sequence alignment, phylogeneUc analysis, bioinformaUcs expression and sequence motif pattern identification, were used to identify soybean genes involved in day length perception and photoperiodic flowering induction. We have investigated approximately 330 000 sequences from open-access databases and have identified all bona fide central oscillator genes and circadian photoreceptors from A. thaliana in soybean sequence databases. We propose a working model for the photoperiodic control of flowering time in G. max, based on the identified key components. These results demonstrate the power of comparative genomics between model systems and crop species to elucidate the several aspects of plant physiology and metabolism.
文摘Circadian clocks synchronize internal physiological responses to occur at the most optimal time of the day.In plants,hormone signaling is under the control of this clock.It has been previously shown that the circadian clock moderates the plant’s sensitivity to gibberellin(GA)by regulating the expression of GA receptors.Recently,two papers by Nohales and Kay(2019)and Park et al.(2020)revealed that post-translational regulation of DELLA proteins by the circadian clock also contributes to timing when the plant is most sensitive to GA.
文摘In this artice Figs.2 and 3 were wrongly numbered;Fig.2 should have been Fig.3 and vice versa as shown below.Moreover,the Fig.3 indications have been revised as shown:the sentence"Next,two transfer DNA(T-DNA)insertion single-mutant prmt6-1(Sail 385_A06)and prmt6-2(Salk 151679C)(Figs.2A;S3)..'has been revised as“Next,two transfer DNA(T-DNA)inser-tion single-mutant prmt6-1(Sail 385_A06)and prmt6-2(Salk 151679C)(Figs.3A;S3..".
基金supported by grants from the Chinese Academy of Sciences(XDA24010101)the Biological Breeding-National Science and Technology Major Project(2024ZD04077)+2 种基金the National Key Research and Development Program of China(2023YFF1001200)Natural Science Foundation of Zhejiang Province(LD24C130001)the Agricultural Science and Technology Innovation Program(ASTIP)of CAAS。
文摘A later heading date generally leads to higher grain yield in favorable ecological regions;however,grain yield reaches a limit as the heading date exceeds a certain threshold.Ghd7 is the first cloned major gene that regulates heading date,plant height and grain number.Here,we investigated the relationship between Ghd7 and florigen genes Hd3a and RFT1,to determine their roles in regulating heading date and grain number under different photoperiods.Our results revealed that under long-day(LD)conditions,Hd3a acts prior to RFT1 to promote heading while negatively regulating plant height and grain number.In contrast,Ghd7 positively regulates heading date,plant height,and grain number by inhibiting both Hd3a and RFT1.Under short-day(SD)conditions,the functions of Hd3a and RFT1 remain consistent with those under LD conditions,but Ghd7 does not inhibit their expression,resulting in a weaker phenotypic effect compared to Hd3a.Additionally,under both LD and SD conditions,increased Ghd7 expression enhances its inhibitory effect on Hd3a and RFT1,leading to later heading and increased grain number;however,once the heading date exceeds 94 d,grain number no longer increases.Moreover,the gn1a allele increased grain number by 16.5%to 42.5%,while combinations of the elite alleles from Ghd7,Hd3a,RFT1,and Gn1a significantly increased grain number by up to 240.9%.Therefore,we propose a new breeding strategy to optimize the heading date and grain number using the Ghd7Hd3aRFT1gn1a combination of Ghd7,Hd3a,RFT1,and Gn1a under LD conditions,and the Ghd7hd3aRFT1gn1a combination under SD conditions.This strategy improved the yield of the high-quality Northeast variety Kongyu 131(KY131)by 69.1%in Beijing and 93.7%in Hainan.This strategy will greatly improve the efficiency of north-to-south adaptation in rice,providing theoretical guidance for expanding the geographical adaptability of rice varieties.
基金supported by the Ministry of Science and Technology(No:2019FY101602).
文摘Climate warming is reshaping the phenology of plants in recent decades,with potential implications for forest productivity,carbon sequestration,and ecosystem functioning.While the effects of warming on secondary growth phenology is becoming increasingly clear,the influenceof environmental factors on different developmental phases of xylem remains to be quantified.In this study,we investigated the temporal dynamics of xylem cell enlargement,wall-thickening,and the interval between these events in twelve temperate tree species from Northeast China over the period 2019–2024.We found that both cell enlargement and wall-thickening advanced significantlyin response to climate warming,with species-specific variations in the rate of advancement.Importantly,the advancing rate of wallthickening was greater than that of cell enlargement,leading to a shortening of the interval between these two events.Linear mixed-effects models revealed that photoperiod,forcing temperature,and precipitation were the primary environmental drivers influencingthe timing of both cell enlargement and wall-thickening,with photoperiod emerging as the most important factor.These results suggest that climate warming accelerates the heat accumulation required for the transition from xylem cell enlargement to wall-thickening,thereby shortening the time interval between these two developmental stages.Beyond contributing valuable multi-year xylem phenological data,our results provide mechanistic insights that enhance predictions of wood formation dynamics under future climate scenarios and improve the accuracy of forest carbon models.
基金supported by grants from the National Natural Science Foundation of China(32172547).
文摘Photoperiod and temperature are crucial factors that trigger flowering in Brassica juncea(B.juncea).However,the underlying regulatory mechanisms remain poorly understood.The MADS-box transcription factor AGL18 acts as a pivotal repressor of floral transition and functions redundantly with AGL15.In this study,we isolated BjuAGL18-1 from B.juncea and identified two unique transcripts,resulting in two distinct proteins:a full-length protein,BjuAGL18-1L,and a truncated protein,BjuAGL18-1S.Further investigation showed that the two isoforms had similar subcellular localizations but different expression patterns in various plant tissues.Notably,BjuAGL18-1L and BjuAGL18-1S were abundantly induced under short-and long-day photoperiods,respectively.BjuAGL18-1L overexpression in B.juncea and Arabidopsis thaliana(A.thaliana)led to late flowering,whereas BjuAGL18-1S overexpression resulted in early flowering.Yeast two-hybrid,bimolecular fluorescent complementation,and luciferase complementation assays showed that BjuAGL18-1L,but not BjuAGL18-1S(which lacked the EAR motif),interacted with the co-repressor BjuAFR2 and the histone deacetylase BjuHDA9 to form a multiprotein complex.Further analysis indicated that BjuAGL18-1L could also form a complex with BjuAGL15 and bind to the BjuFUL promoter,thus inhibiting its expression.However,BjuAGL18-1S interacted with BjuAGL18-1L to form heterodimers,which attenuated their activities,likely by disrupting their binding to target genes,resulting in accelerated flowering progression.These results suggest that BjuAGL18-1 is involved in photoperiod-induced flowering via different regulatory mechanisms in B.juncea.
