The female inflorescence,or ear,of maize develops no branch meristem(BM),which differs from the male inforescence,or tassel.While the mutations of some well documented genes,such as fea2/3/4 and ramosa1/2/3,can cause ...The female inflorescence,or ear,of maize develops no branch meristem(BM),which differs from the male inforescence,or tassel.While the mutations of some well documented genes,such as fea2/3/4 and ramosa1/2/3,can cause the branched architecture of ears in maize,such mutations also change the normal phenotypic performance of the tassels.In the present study,a natural maize mutant with branched ears,named branched ear1(be1),was characterized.be1 shows several branched ears at the base of the central ear with unchanged architecture of the tassels.Besides,both the branched and central ears of be1 possess regularly arranged kerels.The phenotypic characteristics of be1 differ completely from those reported mutants of fasciated ears or RAMOSA-like ears in maize.An SEM survey at the very early development stage showed that meristems with three protrusions,similar to the BM in tassels,were present during the development of the branched ears in be1.Gene mapping and sequence alignment suggested that TEOSINTE BRANCHED1(TB1)was the candidate gene of BE1.Further verification showed that a be1-specific 31 bp deletion at the downstream of BE1 led to statistically reduced expression of this gene in the immature ear,which serves as the potential causal reason for the branched ears of be1.CRISPR/Cas9-based gene editing downstream of TB1 complemented the phenotypic architecture of branched ears,suggesting that TB1 was the target of BE1,and it was named as Zm TB1be1.The results of the present study implied a novel function of TB1 in female inforescence development,rather than shaping the plant architecture in maize.Meanwhile,further functional dissection of ZmTB1be1might shed new light on TB1,the most famous domestication related gene in maize.展开更多
In this study,a linkage genetic map was constructed using a F2 population derived from a cross between a elite maize inbred,B73,and its progenitor,Teosinte（Z.mays ssp.mexicana）,through 205 simple sequence repeat（SS...In this study,a linkage genetic map was constructed using a F2 population derived from a cross between a elite maize inbred,B73,and its progenitor,Teosinte（Z.mays ssp.mexicana）,through 205 simple sequence repeat（SSR） markers and one morphological marker.By Mapmaker 3.0,polymorphic markers were clustered into 10 groups,covering 10 chromosomes of maizexteosinte,with a total length of 2 002.4 cM and an average interval of 9.7 cM.Genotyping errors were detected using R/QTL（LOD=2.0） in 109 markers referring to 176 individuals,distributed across all 10 chromosomes with a ratio 1.2%.Projected error loci were re-run and 304 out of the 460 were confirmed as errors and replaced.A new linkage map was constructed,in which markers maintained the same order but the total map length decreased to 1 947.8 cM,with an average interval of 9.4 cM between markers.In total,25.2%（P0.05） markers were identified to have segregation distortion,in which 34.6% deviated towards the pollination parent（B73）,30.8% deviated towards Teosinte,32.7% deviated towards heterozygote and 1.9% deviated towards both parents.This map was also compared with published maizexteosinte and maize IBM map.展开更多
Natural alleles controlling multiple disease resistances (MDR) are valuable for crop breeding. However, only one MDR gene have been cloned in maize, and molecular mechanisms of MDR are not clear. By map-based cloning,...Natural alleles controlling multiple disease resistances (MDR) are valuable for crop breeding. However, only one MDR gene have been cloned in maize, and molecular mechanisms of MDR are not clear. By map-based cloning, we have cloned a teosinte-derived allele of a resistance gene, Mexicana lesion mimic 1 (ZmMM1), which has a lesion mimic phenotype and confers resistance to northern leaf blight (NLB), gray leaf spot (GLS) and southern corn rust (SCR). Strong MDR conferred by the teosinte allele is linked with the polymorphisms in the 3' untranslated region of the ZmMM1 gene that cause increased accumulation of ZmMM1 protein. ZmMM1 acts as a transcription repressor and negatively regulates transcription of specific target genes including ZmMM1-target gene 3 (ZmMT3), which functions as a negative regulator of plant immunity and associated cell death. The successful isolation of the ZmMM1 resistance gene will help not only in developing broad-spectrum and durable disease resistance but also in understanding the molecular mechanisms underlying MDR.展开更多
Gene expression regulation plays an important role in controlling plant phenotypes and adaptation. Here, we report a comprehensive assessment of gene expression variation through the transcriptome analyses of a large ...Gene expression regulation plays an important role in controlling plant phenotypes and adaptation. Here, we report a comprehensive assessment of gene expression variation through the transcriptome analyses of a large maize-teosinte experimental population. Genome-wide mapping identified 25 660 expression quantitative trait loci （eQTL） for 17 311 genes, capturing an unprecedented range of expression variation. We found that local eQTL were more frequently mapped to adjacent genes, displaying a mode of expression piggybacking, which consequently created co-regulated gene clusters. Genes within the co-regulated gene clusters tend to have relevant functions and shared chromatin modifications. Distant eQTL formed 125 significant distant eQTL hotspots with their targets significantly enriched in specific functional cate- gories. By integrating different sources of information, we identified putative trans- regulators for a variety of metabolic pathways. We demonstrated that the bHLH transcription factor R1 and hexokinase HEX9 might act as crucial regulators for flavonoid biosynthesis and glycolysis, respectively. Moreover, we showed that domestication or improvement has significantly affected global gene expression, with many genes targeted by selection. Of particular interest, the Bx genes for benzoxazinoid biosynthesis may have undergone coordinated cis-regulatory divergence between maize and teosinte, and a transposon insertion that inactivates Bx12 was under strong selection as maize spread into temperate environments with a distinct herbivore community.展开更多
Leaf cells undergo two main developmental events;i.e., cell proliferation and cell differentiation, before maturation. These events occur sequentially at specific positions and with specific timing during leaf develop...Leaf cells undergo two main developmental events;i.e., cell proliferation and cell differentiation, before maturation. These events occur sequentially at specific positions and with specific timing during leaf development. To understand the transition from cell proliferation to cell differentiation of rice leaves, we analyzed rice leaves from both morphological and molecular viewpoints. The results of anatomical, morphological, and histochemical analyses indicated that P4 leaf primordium is the stage when dynamic transition of the cellular state from immature to mature along the proximal-distal axis of the leaf occurs. We screened for marker genes showing a dynamic expression pattern along the proximal-distal axis of the P4 leaf, and applied them to expression analysis in wild-type and various morphogenetic mutants. The changes in expression pattern of the marker genes varied between developmental stages and between mutants. Our analysis reinforced previous data regarding the developmental transition of wild-type rice leaves and indicated that the transition can be monitored using our molecular markers. The results of this study indicate that expression analysis using these molecular markers would be valuable for understanding the genetic effects on leaf development in various leaf morphogenetic mutants.展开更多
Domestication and genetic improvement of maize improve yield and stress tolerance due to changes in morphological and physiological properties, which likely alter rhizosphere microbial diversity. Understanding how the...Domestication and genetic improvement of maize improve yield and stress tolerance due to changes in morphological and physiological properties, which likely alter rhizosphere microbial diversity. Understanding how the evolution of maize germplasm impacts its rhizobacterial traits during the growth stage is important for optimizing plant-microbe associations and obtaining yield gain in domesticated germplasms. In this study, a total of nine accessions representing domestication and subsequent genetic improvement were selected. We then sequenced the plant DNA and rhizobacterial DNA of teosinte, landraces and inbred lines at the seedling, flowering and maturity stages in a field trial. Moreover, the soil chemical properties were determined at the respective stages to explore the associations of soil characteristics with bacterial community structures. The results showed that domestication and genetic improvement increased the rhizobacterial diversity and substantially altered the rhizobacterial community composition. The core microbiome in the rhizosphere differed among germplasm groups. The co-occurrence network analysis demonstrated that the modularity in the bacterial network of the inbred lines was greater than those of teosinte and the landraces. In conclusion, the increased diversity of the rhizobacterial community with domestication and genetic improvement may improve maize resilience to biotic stresses and soil nutrient availability to plants.展开更多
Zea nicaraguensis, a wild relative of cultivated maize （Zea mays subsp, mays）, is considered to be a valuable germplasm to improve the waterlogging tolerance of cultivated maize. Use of reverse genetic-based gene cl...Zea nicaraguensis, a wild relative of cultivated maize （Zea mays subsp, mays）, is considered to be a valuable germplasm to improve the waterlogging tolerance of cultivated maize. Use of reverse genetic-based gene cloning and function verifi- cation to discover waterlogging tolerance genes in Z. nicaraguensis is currently impractical, because little gene sequence information for Z. nicaraguensis is available in public databases. In this study, Z. nicaraguensis seedlings were subjected to simulated waterlogging stress and total RNAs were isolated from roots stressed and non-stressed controls. In total, 80 mol L-1 Illumina 100-bp paired-end reads were generated. De novo assembly of the reads generated 81 002 final non-re- dundant contigs, from which 5 261 full-length transcripts were identified. Among these full-length transcripts, 3 169 had at least one Gene Ontology （GO） annotation, 2 354 received cluster of orthologous groups （COG） terms, and 1 992 were assigned a Kyoto encyclopedia of genes and genomes （KEGG） Orthology number. These sequence data represent a valuable resource for identification of Z. nicaraguensis genes involved in waterlogging response.展开更多
Maize(Zea mays ssp.mays)was domesticated approximately 9,000 years ago from Zea mays ssp.parviglumis,a lowland teosinte native to southwestern Mexico(Matsuoka et al.,2002).From the tropical origin,maize has spread int...Maize(Zea mays ssp.mays)was domesticated approximately 9,000 years ago from Zea mays ssp.parviglumis,a lowland teosinte native to southwestern Mexico(Matsuoka et al.,2002).From the tropical origin,maize has spread into a wide range of temperate regions with high latitudes and altitudes.Flowering time is a critical trait determining plant local adaptation.Several flowering time genes contributing to maize latitudinal adaptation have been identified(Yang et al.,2013;Guo et al.,2018;Huang et al.,2018;Liang et al.,2019;Wu et al.,2023).In contrast,the genetic mechanisms enabling maize adaptation to high-altitude environments remain poorly understood.展开更多
As an important yield component,rice tiller number controls panicle number and determines grain yield.Regulation of rice tiller number by chloroplast pentatricopeptide repeat(PPR)proteins has not been reported previou...As an important yield component,rice tiller number controls panicle number and determines grain yield.Regulation of rice tiller number by chloroplast pentatricopeptide repeat(PPR)proteins has not been reported previously.Here,we report the rice reduced culm number22(rcn22)mutant,which produces few tillers owing to suppressed tiller bud elongation.Map-based cloning revealed that RCN22 encodes a chloroplast-localized P-type PPR protein.We found that RCN22 specifically binds to the 5′UTR of RbcL mRNA(encoding the large subunit of Rubisco)and enhances its stability.The reduced abundance of RbcL mRNA in rcn22 leads to a lower photosynthetic rate and decreased sugar levels.Consequently,transcript levels of DWARF3(D3)and TEOSINTE BRANCHED1(TB1)(which encode negative regulators of tiller bud elongation)are increased,whereas protein levels of the positive regulator DWARF53(D53)are decreased.Furthermore,high concentrations of sucrose can rescue the tiller bud growth defect of the rcn22 mutant.On the other hand,TB1 directly binds to the RCN22 promoter and downregulates its expression.The tb1/rcn22 double mutant shows a tillering phenotype similar to that of rcn22.Our results suggest that the TB1–RCN22–RbcL module plays a vital role in rice tiller bud elongation by affecting sugar levels.展开更多
Investigating how crop domestication and early farming mediated crop attributes, distributions, and interactions with antagonists may shed light on today's agricultural pest problems. Crop domestication generally ...Investigating how crop domestication and early farming mediated crop attributes, distributions, and interactions with antagonists may shed light on today's agricultural pest problems. Crop domestication generally involved artificial selection for traits desirable to early farmers, for example, in creased productivity or yield, and enhanced qualities, though invariably it altered the interactions between crops and insects, and expanded the geographical ranges of crops. Thus, some studies suggest that with crop domestication and spread, insect populations on wild crop ancestors gave rise to pestiferous insect populations on crops. Here, we addressed whether the emergence of corn leafhopper (Dalbulus ma id is) as an agricultural pest may be associated with domestication and early spread of maize (Zea mays mays). We used AFLP markers and mitochondrial COI sequences to assess population genetic structuring and haplotype relationships among corn leafhopper samples from maize and its wild relative Zea diploperennis from multiple locations in Mexico and Argentina. We uncovered seven corn leafhopper haplotypes contained within two haplogroups, one haplogroup containing haplotypes associated with maize and the other containing haplotypes associated with Z. diploperennis in a mountainous habitat. Within the first haplogroup, one haplotype was predominant across Mexican locations, and another across Argentinean locations;both were considered pestiferous. We suggested that the divergence times of the maize-associated haplogroup and of the "pestiferous" haplotypes are correlated with the chronology of maize spread following its domestication. Overall, our results support a hypothesis positing that maize domestication favored corn leafhopper genotypes preadapted for exploiting maize so that they became pestiferous, and that with the geographical expansi on of maize farming, corn leafhopper colonized Z. diploperennis, a host exclusive to secluded habitats that serves as a refuge for archaic corn leafhopper genotypic diversity. Broadly, our results help explain the extents to which crop domestication and early spread may have mediated the emergence of today's agricultural pests.展开更多
基金supported by the Special Key Project for Technological Innovation and Application Development in Chongqing,China(CSTB2022TIAD-KPX0011)the Special Fund for Youth Team of the Southwest Universities,China(SWU-XJPY202306)+1 种基金the Natural Science Foundation of Chongqing,China(cstc2021jcyj-msxmX0583)the Fundamental Research Funds for the Central Universities of Southwest University,China(S202210635326)。
文摘The female inflorescence,or ear,of maize develops no branch meristem(BM),which differs from the male inforescence,or tassel.While the mutations of some well documented genes,such as fea2/3/4 and ramosa1/2/3,can cause the branched architecture of ears in maize,such mutations also change the normal phenotypic performance of the tassels.In the present study,a natural maize mutant with branched ears,named branched ear1(be1),was characterized.be1 shows several branched ears at the base of the central ear with unchanged architecture of the tassels.Besides,both the branched and central ears of be1 possess regularly arranged kerels.The phenotypic characteristics of be1 differ completely from those reported mutants of fasciated ears or RAMOSA-like ears in maize.An SEM survey at the very early development stage showed that meristems with three protrusions,similar to the BM in tassels,were present during the development of the branched ears in be1.Gene mapping and sequence alignment suggested that TEOSINTE BRANCHED1(TB1)was the candidate gene of BE1.Further verification showed that a be1-specific 31 bp deletion at the downstream of BE1 led to statistically reduced expression of this gene in the immature ear,which serves as the potential causal reason for the branched ears of be1.CRISPR/Cas9-based gene editing downstream of TB1 complemented the phenotypic architecture of branched ears,suggesting that TB1 was the target of BE1,and it was named as Zm TB1be1.The results of the present study implied a novel function of TB1 in female inforescence development,rather than shaping the plant architecture in maize.Meanwhile,further functional dissection of ZmTB1be1might shed new light on TB1,the most famous domestication related gene in maize.
基金supported by the National High-Tech R&D Program of China(2006AA10Z183,2006AA10A107)
文摘In this study,a linkage genetic map was constructed using a F2 population derived from a cross between a elite maize inbred,B73,and its progenitor,Teosinte（Z.mays ssp.mexicana）,through 205 simple sequence repeat（SSR） markers and one morphological marker.By Mapmaker 3.0,polymorphic markers were clustered into 10 groups,covering 10 chromosomes of maizexteosinte,with a total length of 2 002.4 cM and an average interval of 9.7 cM.Genotyping errors were detected using R/QTL（LOD=2.0） in 109 markers referring to 176 individuals,distributed across all 10 chromosomes with a ratio 1.2%.Projected error loci were re-run and 304 out of the 460 were confirmed as errors and replaced.A new linkage map was constructed,in which markers maintained the same order but the total map length decreased to 1 947.8 cM,with an average interval of 9.4 cM between markers.In total,25.2%（P0.05） markers were identified to have segregation distortion,in which 34.6% deviated towards the pollination parent（B73）,30.8% deviated towards Teosinte,32.7% deviated towards heterozygote and 1.9% deviated towards both parents.This map was also compared with published maizexteosinte and maize IBM map.
基金This work was supported by the National Key Research and Development Program of China(2016YFD0101002)the National Natural Science Foundation of China(31571676,32072007,and 31761143008)+4 种基金the Ministry of Science and Technology of the People's Republic of China(2015BAD02B01)the Fundamental Research Funds for the Central Universities(2014PY054 and 2662015PY185)the University Student Research Fund(2016090)the Innovation Training Plan of University Student Fund(201510504023)the Higher Education Discipline Innovation Project(B20051).
文摘Natural alleles controlling multiple disease resistances (MDR) are valuable for crop breeding. However, only one MDR gene have been cloned in maize, and molecular mechanisms of MDR are not clear. By map-based cloning, we have cloned a teosinte-derived allele of a resistance gene, Mexicana lesion mimic 1 (ZmMM1), which has a lesion mimic phenotype and confers resistance to northern leaf blight (NLB), gray leaf spot (GLS) and southern corn rust (SCR). Strong MDR conferred by the teosinte allele is linked with the polymorphisms in the 3' untranslated region of the ZmMM1 gene that cause increased accumulation of ZmMM1 protein. ZmMM1 acts as a transcription repressor and negatively regulates transcription of specific target genes including ZmMM1-target gene 3 (ZmMT3), which functions as a negative regulator of plant immunity and associated cell death. The successful isolation of the ZmMM1 resistance gene will help not only in developing broad-spectrum and durable disease resistance but also in understanding the molecular mechanisms underlying MDR.
文摘Gene expression regulation plays an important role in controlling plant phenotypes and adaptation. Here, we report a comprehensive assessment of gene expression variation through the transcriptome analyses of a large maize-teosinte experimental population. Genome-wide mapping identified 25 660 expression quantitative trait loci （eQTL） for 17 311 genes, capturing an unprecedented range of expression variation. We found that local eQTL were more frequently mapped to adjacent genes, displaying a mode of expression piggybacking, which consequently created co-regulated gene clusters. Genes within the co-regulated gene clusters tend to have relevant functions and shared chromatin modifications. Distant eQTL formed 125 significant distant eQTL hotspots with their targets significantly enriched in specific functional cate- gories. By integrating different sources of information, we identified putative trans- regulators for a variety of metabolic pathways. We demonstrated that the bHLH transcription factor R1 and hexokinase HEX9 might act as crucial regulators for flavonoid biosynthesis and glycolysis, respectively. Moreover, we showed that domestication or improvement has significantly affected global gene expression, with many genes targeted by selection. Of particular interest, the Bx genes for benzoxazinoid biosynthesis may have undergone coordinated cis-regulatory divergence between maize and teosinte, and a transposon insertion that inactivates Bx12 was under strong selection as maize spread into temperate environments with a distinct herbivore community.
文摘Leaf cells undergo two main developmental events;i.e., cell proliferation and cell differentiation, before maturation. These events occur sequentially at specific positions and with specific timing during leaf development. To understand the transition from cell proliferation to cell differentiation of rice leaves, we analyzed rice leaves from both morphological and molecular viewpoints. The results of anatomical, morphological, and histochemical analyses indicated that P4 leaf primordium is the stage when dynamic transition of the cellular state from immature to mature along the proximal-distal axis of the leaf occurs. We screened for marker genes showing a dynamic expression pattern along the proximal-distal axis of the P4 leaf, and applied them to expression analysis in wild-type and various morphogenetic mutants. The changes in expression pattern of the marker genes varied between developmental stages and between mutants. Our analysis reinforced previous data regarding the developmental transition of wild-type rice leaves and indicated that the transition can be monitored using our molecular markers. The results of this study indicate that expression analysis using these molecular markers would be valuable for understanding the genetic effects on leaf development in various leaf morphogenetic mutants.
基金supported by the Key Area Research and Development Program of Guangdong Province,China(2018B020202013)the National Key R&D Program of China(2018YFD1000903)the Natural Science Foundation of Guangdong Province,China(2018A030313865)。
文摘Domestication and genetic improvement of maize improve yield and stress tolerance due to changes in morphological and physiological properties, which likely alter rhizosphere microbial diversity. Understanding how the evolution of maize germplasm impacts its rhizobacterial traits during the growth stage is important for optimizing plant-microbe associations and obtaining yield gain in domesticated germplasms. In this study, a total of nine accessions representing domestication and subsequent genetic improvement were selected. We then sequenced the plant DNA and rhizobacterial DNA of teosinte, landraces and inbred lines at the seedling, flowering and maturity stages in a field trial. Moreover, the soil chemical properties were determined at the respective stages to explore the associations of soil characteristics with bacterial community structures. The results showed that domestication and genetic improvement increased the rhizobacterial diversity and substantially altered the rhizobacterial community composition. The core microbiome in the rhizosphere differed among germplasm groups. The co-occurrence network analysis demonstrated that the modularity in the bacterial network of the inbred lines was greater than those of teosinte and the landraces. In conclusion, the increased diversity of the rhizobacterial community with domestication and genetic improvement may improve maize resilience to biotic stresses and soil nutrient availability to plants.
基金supported by the Basic Research Program of China (973 Program, 2014CB138705)the National Natural Science Foundation of China (31371639)the Sichuan Youth Science and Technology Foundation of China (12ZB091)
文摘Zea nicaraguensis, a wild relative of cultivated maize （Zea mays subsp, mays）, is considered to be a valuable germplasm to improve the waterlogging tolerance of cultivated maize. Use of reverse genetic-based gene cloning and function verifi- cation to discover waterlogging tolerance genes in Z. nicaraguensis is currently impractical, because little gene sequence information for Z. nicaraguensis is available in public databases. In this study, Z. nicaraguensis seedlings were subjected to simulated waterlogging stress and total RNAs were isolated from roots stressed and non-stressed controls. In total, 80 mol L-1 Illumina 100-bp paired-end reads were generated. De novo assembly of the reads generated 81 002 final non-re- dundant contigs, from which 5 261 full-length transcripts were identified. Among these full-length transcripts, 3 169 had at least one Gene Ontology （GO） annotation, 2 354 received cluster of orthologous groups （COG） terms, and 1 992 were assigned a Kyoto encyclopedia of genes and genomes （KEGG） Orthology number. These sequence data represent a valuable resource for identification of Z. nicaraguensis genes involved in waterlogging response.
基金supported by the National Key Research and Development Program of China(2023YFF1000401)the National Natural Science Foundation of China(32025027),Pinduoduo-China Agricultural University Research Fund(PC2023A01003)+2 种基金New Cornerstone Science Foundation through the XPLORER PRIZE,Hainan Yazhou Bay Seed Laboratory(B21HJ0111)Sanya Yazhouwan Science and Technology City Administration(SYND-2022-26)the Chinese Universities Scientific Fund(2020TC149 and 2022TC138).
文摘Maize(Zea mays ssp.mays)was domesticated approximately 9,000 years ago from Zea mays ssp.parviglumis,a lowland teosinte native to southwestern Mexico(Matsuoka et al.,2002).From the tropical origin,maize has spread into a wide range of temperate regions with high latitudes and altitudes.Flowering time is a critical trait determining plant local adaptation.Several flowering time genes contributing to maize latitudinal adaptation have been identified(Yang et al.,2013;Guo et al.,2018;Huang et al.,2018;Liang et al.,2019;Wu et al.,2023).In contrast,the genetic mechanisms enabling maize adaptation to high-altitude environments remain poorly understood.
基金Biological Breeding-National Science and Technology Major Project of China(2023ZD0406801)Innovation Program of Chinese Academy of Agricultural Sciences(CAAS-CSCB-202402)+1 种基金National Natural Science Foundation of China(32270373,32270653)Agricultural Variety Improvement Project of Shandong Province,China(2021LZGC020).
文摘As an important yield component,rice tiller number controls panicle number and determines grain yield.Regulation of rice tiller number by chloroplast pentatricopeptide repeat(PPR)proteins has not been reported previously.Here,we report the rice reduced culm number22(rcn22)mutant,which produces few tillers owing to suppressed tiller bud elongation.Map-based cloning revealed that RCN22 encodes a chloroplast-localized P-type PPR protein.We found that RCN22 specifically binds to the 5′UTR of RbcL mRNA(encoding the large subunit of Rubisco)and enhances its stability.The reduced abundance of RbcL mRNA in rcn22 leads to a lower photosynthetic rate and decreased sugar levels.Consequently,transcript levels of DWARF3(D3)and TEOSINTE BRANCHED1(TB1)(which encode negative regulators of tiller bud elongation)are increased,whereas protein levels of the positive regulator DWARF53(D53)are decreased.Furthermore,high concentrations of sucrose can rescue the tiller bud growth defect of the rcn22 mutant.On the other hand,TB1 directly binds to the RCN22 promoter and downregulates its expression.The tb1/rcn22 double mutant shows a tillering phenotype similar to that of rcn22.Our results suggest that the TB1–RCN22–RbcL module plays a vital role in rice tiller bud elongation by affecting sugar levels.
文摘Investigating how crop domestication and early farming mediated crop attributes, distributions, and interactions with antagonists may shed light on today's agricultural pest problems. Crop domestication generally involved artificial selection for traits desirable to early farmers, for example, in creased productivity or yield, and enhanced qualities, though invariably it altered the interactions between crops and insects, and expanded the geographical ranges of crops. Thus, some studies suggest that with crop domestication and spread, insect populations on wild crop ancestors gave rise to pestiferous insect populations on crops. Here, we addressed whether the emergence of corn leafhopper (Dalbulus ma id is) as an agricultural pest may be associated with domestication and early spread of maize (Zea mays mays). We used AFLP markers and mitochondrial COI sequences to assess population genetic structuring and haplotype relationships among corn leafhopper samples from maize and its wild relative Zea diploperennis from multiple locations in Mexico and Argentina. We uncovered seven corn leafhopper haplotypes contained within two haplogroups, one haplogroup containing haplotypes associated with maize and the other containing haplotypes associated with Z. diploperennis in a mountainous habitat. Within the first haplogroup, one haplotype was predominant across Mexican locations, and another across Argentinean locations;both were considered pestiferous. We suggested that the divergence times of the maize-associated haplogroup and of the "pestiferous" haplotypes are correlated with the chronology of maize spread following its domestication. Overall, our results support a hypothesis positing that maize domestication favored corn leafhopper genotypes preadapted for exploiting maize so that they became pestiferous, and that with the geographical expansi on of maize farming, corn leafhopper colonized Z. diploperennis, a host exclusive to secluded habitats that serves as a refuge for archaic corn leafhopper genotypic diversity. Broadly, our results help explain the extents to which crop domestication and early spread may have mediated the emergence of today's agricultural pests.
