Arabidopsis trichomes are large branched single cells that protrude from the epidermis. The first mor- phological indication of trichome development is an increase in nuclear content resulting from an initial cycle of...Arabidopsis trichomes are large branched single cells that protrude from the epidermis. The first mor- phological indication of trichome development is an increase in nuclear content resulting from an initial cycle of endoreduplication. Our previous study has shown that the C2H2 zinc finger protein GLABROUS INFLORESCENCE STEMS (GIS) is required for trichome initiation in the inflorescence organ and for trichome branching in response to gibberellic acid signaling, although GIS gene does not play a direct role in regulating trichome cell division. Here, we describe a novel role of GIS, controlling trichome cell division indirectly by interacting genetically with a key endoreduplication regulator SIAMESE (SIM). Our molecular and genetic studies have shown that GIS might indireclty control cell division and trichome branching by acting downstream of SIM. A loss of function mutation of SIM signficantly reduced the expression of GIS. Futhermore, the overexpression of GIS rescued the trichome cluster cell phenotypes of sim mutant. The gain or loss of function of GIS had no significant effect on the expression of SIM. These results suggest that GIS may play an indirect role in regulating trichome cell division by genetically interacting with SIM.展开更多
Objective:Effective adjuvant therapeutic strategies are urgently needed to overcome MAPK inhibitor(MAPKi)resistance,which is one of the most common forms of resistance that has emerged in many types of cancers.Here,we...Objective:Effective adjuvant therapeutic strategies are urgently needed to overcome MAPK inhibitor(MAPKi)resistance,which is one of the most common forms of resistance that has emerged in many types of cancers.Here,we aimed to systematically identify the genetic interactions underlying MAPKi resistance,and to further investigate the mechanisms that produce the genetic interactions that generate synergistic MAPKi resistance.Methods:We conducted a comprehensive pair-wise sgRNA-based high-throughput screening assay to identify synergistic interactions that sensitized cancer cells to MAPKi,and validated 3 genetic combinations through competitive growth,cell viability,and spheroid formation assays.We next conducted Kaplan-Meier survival analysis based on The Cancer Genome Atlas database and conducted immunohistochemistry to determine the clinical relevance of these synergistic combinations.We also investigated the MAPKi resistance mechanisms of these validated synergistic combinations by using co-immunoprecipitation,Western blot,qRTPCR,and immunofluorescence assays.Results:We constructed a systematic interaction network of MAPKi resistance and identified 3 novel synergistic combinations that effectively targeted MAPKi resistance(ITGB3+IGF1R,ITGB3+JNK,and HDGF+LGR5).We next analyzed their clinical relevance and the mechanisms by which they sensitized cancer cells to MAPKi exposure.Specifically,we discovered a novel protein complex,HDGF-LGR5,that adaptively responded to MAPKi to enhance cancer cell stemness,which was up-or downregulated by the inhibitors of ITGB3+JNK or ITGB3+IGF1R.Conclusions:Pair-wise sgRNA library screening provided systematic insights into elucidating MAPKi resistance in cancer cells.ITGB3-+IGF1R-targeting drugs(cilengitide+linsitinib)could be used as an effective therapy for suppressing the adaptive formation of the HDGF-LGR5 protein complex,which enhanced cancer stemness during MAPKi stress.展开更多
Noises widely exist in interactive genetic algorithms. However, there is no effective method to solve this problem up to now. There are two kinds of noises, one is the noise existing in visual systems and the other is...Noises widely exist in interactive genetic algorithms. However, there is no effective method to solve this problem up to now. There are two kinds of noises, one is the noise existing in visual systems and the other is resulted from user’s preference mechanisms. Characteristics of the two noises are presented aiming at the application of interac- tive genetic algorithms in dealing with images. The evolutionary phases of interactive genetic algorithms are determined according to differences in the same individual’s fitness among different generations. Models for noises in different phases are established and the corresponding strategies for reducing noises are given. The algorithm proposed in this paper has been applied to fashion design, which is a typical example of image processing. The results show that the strategies can reduce noises in interactive genetic algorithms and improve the algorithm’s performance effectively. However, a further study is needed to solve the problem of determining the evolution phase by using suitable objective methods so as to find out an effective method to decrease noises.展开更多
We propose a surrogate model-assisted algorithm by using a directed fuzzy graph to extract a user’s cognition on evaluated individuals in order to alleviate user fatigue in interactive genetic algorithms with an indi...We propose a surrogate model-assisted algorithm by using a directed fuzzy graph to extract a user’s cognition on evaluated individuals in order to alleviate user fatigue in interactive genetic algorithms with an individual’s fuzzy and stochastic fitness. We firstly present an approach to construct a directed fuzzy graph of an evolutionary population according to individuals’ dominance relations, cut-set levels and interval dominance probabilities, and then calculate an individual’s crisp fitness based on the out-degree and in-degree of the fuzzy graph. The approach to obtain training data is achieved using the fuzzy entropy of the evolutionary system to guarantee the credibilities of the samples which are used to train the surrogate model. We adopt a support vector regression machine as the surrogate model and train it using the sampled individuals and their crisp fitness. Then the surrogate model is optimized using the traditional genetic algorithm for some generations, and some good individuals are submitted to the user for the subsequent evolutions so as to guide and accelerate the evolution. Finally, we quantitatively analyze the performance of the presented algorithm in alleviating user fatigue and increasing more opportunities to find the satisfactory individuals, and also apply our algorithm to a fashion evolutionary design system to demonstrate its efficiency.展开更多
This paper improves the resampling step of particle filtering（PF） based on a broad interactive genetic algorithm to resolve particle degeneration and particle shortage.For target tracking in image processing,this pa...This paper improves the resampling step of particle filtering（PF） based on a broad interactive genetic algorithm to resolve particle degeneration and particle shortage.For target tracking in image processing,this paper uses the information coming from the particles of the previous fame image and new observation data to self-adaptively determine the selecting range of particles in current fame image.The improved selecting operator with jam gene is used to ensure the diversity of particles in mathematics,and the absolute arithmetical crossing operator whose feasible solution space being close about crossing operation,and non-uniform mutation operator is used to capture all kinds of mutation in this paper.The result of simulating experiment shows that the algorithm of this paper has better iterative estimating capability than extended Kalman filtering（EKF）,PF,regularized partide filtering（RPF）,and genetic algorithm（GA）-PF.展开更多
Objective To investigate the interaction between the genes required for the functions of AWA olfactory neuron and insulin/IGF signaling in regulating the longevity of nematode Caenorhabditis elegans （C. elegans）. Me...Objective To investigate the interaction between the genes required for the functions of AWA olfactory neuron and insulin/IGF signaling in regulating the longevity of nematode Caenorhabditis elegans （C. elegans）. Methods The mutants that had loss-of-function mutation of the genes required for AWA, AWC, ASE, and AFD sensory neurons were employed. Lifespan, the speed of pharynx pumping, the intestinal autofluorescence, the dauer formation, and the brood size were examined. Rescue experiments were performed to confrm the role of the genes required for the functions of AWA neuron in regulating lifespan. Moreover, genetic interactions between genes required for the functions of AWA neuron and insulin/ IGF signaling were investigated. Results Mutations of odr-7, odr-2, and odr-3 genes required for the functions of AWA neuron significantly increased the mean lifespan of nematodes and slowed the accumulation of intestinal autofluorescence. Besides, these mutations were closely associated with higher pumping rates during aging. However, mutation of odr-7, odr- 2, or odr-3 did not obviously affect the brood size or the dauer formation, and the regulation of longevity by odr-7, odr-2, and odr-3 was temperature-independent. In contrast, mutations of genes required for the functions of ASE, AWC, and AFD sensory neurons did not infuence the nematode lifespan. Moreover, expression of odr-7, odr-2 and odr-3 in AWA neuron could completely or largely restore the altered lifespan in odr-7, odr-2 and odr-3 mutants. Furthermore, genetic interaction assay demonstrated that the extended lifespan in odr-7 mutant could be suppressed by daf-16 mutation and enhanced by daf- 2 or age-1 mutation, whereas mev-1 and pha-4 were not required for the long lifespan of odr-7 mutant. Conclusion The genes required for the function of AWA sensory neuron could regulate the nematode longevity in an insulin/IGF signaling-dependent fashion in C. elegans.展开更多
The panicle architecture and grain size of rice affect not only grain yield but also grain quality,especially grain appearance.The erect-panicle(EP)trait controlled by the qpe9-1/dep1 allele has been widely used in hi...The panicle architecture and grain size of rice affect not only grain yield but also grain quality,especially grain appearance.The erect-panicle(EP)trait controlled by the qpe9-1/dep1 allele has been widely used in high-yielding japonica rice breeding,but usually accompanied with moderate appearance of milled rice.The null gs9 allele shows a good potential for improving grain shape and appearance.However,GS9 and qPE9-1/DEP1 loci are tightly linked,and their interaction is unclear,which obviously restricts their utilization in modern rice breeding.In the present study,comparative analyses of protein and mRNA levels revealed that GS9 and qPE9-1 function independently.Three nearisogenic lines(NILs)carrying various allelic combinations of these two loci,NIL(gs9/qpe9-1),NIL(GS9/qPE9-1)and NIL(gs9/qPE9-1),in the EP japonica cultivar 2661(GS9/qpe9-1)background were developed for genetic interaction analysis.GS9 and qPE9-1 had additive effects on determining grain size,and the null gs9 allele could decrease grain chalkiness and improve grain appearance without affecting plant and panicle architecture in EP japonica cultivars.Additionally,introgression lines(ILs)developed in another released EP japonica cultivar Wuyujing 27(WYJ27)background showed the same additive effect and the feasibility of utilizing the gs9 allele to improve grain appearance quality in high-yielding EP cultivars.This study provides an effective strategy for rice breeders to improve rice grain appearance in EP japonica and related cultivars.展开更多
With the cultural myth that science can only determine the way the world ＂is＂ （facts）, while humanities, social sciences, lawyers, philosophers, and theologians must determine the way the world ＂ought to be＂ （v...With the cultural myth that science can only determine the way the world ＂is＂ （facts）, while humanities, social sciences, lawyers, philosophers, and theologians must determine the way the world ＂ought to be＂ （values）, those in position of global-, national-, and local-political power make major decisions of the use （or non-use） of scientific knowledge and technology. As a result, the human being has created a non-scientifically based cultural environment that is affecting his ability to survive. In effect, cultural evolution is occurring more rapidly than biological evolution that can adapt to the changes brought about in the physical and psycho-social environments. In a pluralistic cultural world, where each society has generated a different view of human nature and different ethical values, the use, misuse, or non-use of scientific and technological advances are derived from these unscientific views of human nature. Since all life depends on limiting interacting environmental and ecological factors, it is imperative that scientific information be used to govern how to minimize irreversible effects on life-sustaining ecological factors, but also scientific information bearing on understanding human nature ought to be integrated into a ＂global bioethics＂. While ethical values cannot be directly derived from scientific factors, it is also true that human values or our ＂ought＂ cannot be maintained in ignorance or defiance of the facts or the ＂is＂.展开更多
Rice （Oryza sativa） has unique floral patterns that contribute to grain yield. However, the molecular mechanism underlying the specification of floral organ identities in rice, particularly the interaction among flo...Rice （Oryza sativa） has unique floral patterns that contribute to grain yield. However, the molecular mechanism underlying the specification of floral organ identities in rice, particularly the interaction among floral homeotic genes, remains poorly understood. Here, we show that the floral homeotic gene OsMADS16 （also called SUPERWOMAN1, SPWl, a B-class gene） acts together with the rice C-class genes OsMADS3 and OsMADS58 in specifying floral organ patterning. OsMADS16 and the two C-class genes have an overlapping expression pattern in the third whorl founder cells. Compared with the single mutants, both spwl-1 osmads3-4 and spwl-1 osmads58 double mutants exhibit additional whorls of glume-like organs within the flower, particularly an extra whorl of six glume-like structures formed at the position of the wild-type stamens. These ectopic glume-like structures were shown to have palea identity through cellular observation and in situ hybridization analysis using marker genes. Our results suggest that B- and C-class genes play a key role in suppressing indeterminate growth within the floral meristem, particularly whorl-3 primordia. We also hypothesize that, in contrast to previous assumptions, the specialized spikelet organ in rice, the palea, is the counterpart of the sepal in eudicots, and the lemma is homologous to the bract.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 30970167 and 31228002)the Zhejiang Qianjiang Talent Program (No. 2010R10084)+1 种基金the Zhejiang Provincial Natural Science Foundation of China (No. Z31100041)the Zhejiang Province Foundation for Returned Scholars (No. 20100129), China
文摘Arabidopsis trichomes are large branched single cells that protrude from the epidermis. The first mor- phological indication of trichome development is an increase in nuclear content resulting from an initial cycle of endoreduplication. Our previous study has shown that the C2H2 zinc finger protein GLABROUS INFLORESCENCE STEMS (GIS) is required for trichome initiation in the inflorescence organ and for trichome branching in response to gibberellic acid signaling, although GIS gene does not play a direct role in regulating trichome cell division. Here, we describe a novel role of GIS, controlling trichome cell division indirectly by interacting genetically with a key endoreduplication regulator SIAMESE (SIM). Our molecular and genetic studies have shown that GIS might indireclty control cell division and trichome branching by acting downstream of SIM. A loss of function mutation of SIM signficantly reduced the expression of GIS. Futhermore, the overexpression of GIS rescued the trichome cluster cell phenotypes of sim mutant. The gain or loss of function of GIS had no significant effect on the expression of SIM. These results suggest that GIS may play an indirect role in regulating trichome cell division by genetically interacting with SIM.
基金This work was supported by grants from the National Natural Science Foundation of China(Grant Nos.31471255,31771483,81171515,31670991,and 61721003)the National Key Research and Development Program(Grant Nos.2017YFC0908400 and 2017YFC0908401).
文摘Objective:Effective adjuvant therapeutic strategies are urgently needed to overcome MAPK inhibitor(MAPKi)resistance,which is one of the most common forms of resistance that has emerged in many types of cancers.Here,we aimed to systematically identify the genetic interactions underlying MAPKi resistance,and to further investigate the mechanisms that produce the genetic interactions that generate synergistic MAPKi resistance.Methods:We conducted a comprehensive pair-wise sgRNA-based high-throughput screening assay to identify synergistic interactions that sensitized cancer cells to MAPKi,and validated 3 genetic combinations through competitive growth,cell viability,and spheroid formation assays.We next conducted Kaplan-Meier survival analysis based on The Cancer Genome Atlas database and conducted immunohistochemistry to determine the clinical relevance of these synergistic combinations.We also investigated the MAPKi resistance mechanisms of these validated synergistic combinations by using co-immunoprecipitation,Western blot,qRTPCR,and immunofluorescence assays.Results:We constructed a systematic interaction network of MAPKi resistance and identified 3 novel synergistic combinations that effectively targeted MAPKi resistance(ITGB3+IGF1R,ITGB3+JNK,and HDGF+LGR5).We next analyzed their clinical relevance and the mechanisms by which they sensitized cancer cells to MAPKi exposure.Specifically,we discovered a novel protein complex,HDGF-LGR5,that adaptively responded to MAPKi to enhance cancer cell stemness,which was up-or downregulated by the inhibitors of ITGB3+JNK or ITGB3+IGF1R.Conclusions:Pair-wise sgRNA library screening provided systematic insights into elucidating MAPKi resistance in cancer cells.ITGB3-+IGF1R-targeting drugs(cilengitide+linsitinib)could be used as an effective therapy for suppressing the adaptive formation of the HDGF-LGR5 protein complex,which enhanced cancer stemness during MAPKi stress.
基金Project 60575046 supported by the National Natural Science Foundation of China
文摘Noises widely exist in interactive genetic algorithms. However, there is no effective method to solve this problem up to now. There are two kinds of noises, one is the noise existing in visual systems and the other is resulted from user’s preference mechanisms. Characteristics of the two noises are presented aiming at the application of interac- tive genetic algorithms in dealing with images. The evolutionary phases of interactive genetic algorithms are determined according to differences in the same individual’s fitness among different generations. Models for noises in different phases are established and the corresponding strategies for reducing noises are given. The algorithm proposed in this paper has been applied to fashion design, which is a typical example of image processing. The results show that the strategies can reduce noises in interactive genetic algorithms and improve the algorithm’s performance effectively. However, a further study is needed to solve the problem of determining the evolution phase by using suitable objective methods so as to find out an effective method to decrease noises.
基金supported by National Natural Science Foundation of China (No.60775044)the Program for New Century Excellent Talentsin University (No.NCET-07-0802)
文摘We propose a surrogate model-assisted algorithm by using a directed fuzzy graph to extract a user’s cognition on evaluated individuals in order to alleviate user fatigue in interactive genetic algorithms with an individual’s fuzzy and stochastic fitness. We firstly present an approach to construct a directed fuzzy graph of an evolutionary population according to individuals’ dominance relations, cut-set levels and interval dominance probabilities, and then calculate an individual’s crisp fitness based on the out-degree and in-degree of the fuzzy graph. The approach to obtain training data is achieved using the fuzzy entropy of the evolutionary system to guarantee the credibilities of the samples which are used to train the surrogate model. We adopt a support vector regression machine as the surrogate model and train it using the sampled individuals and their crisp fitness. Then the surrogate model is optimized using the traditional genetic algorithm for some generations, and some good individuals are submitted to the user for the subsequent evolutions so as to guide and accelerate the evolution. Finally, we quantitatively analyze the performance of the presented algorithm in alleviating user fatigue and increasing more opportunities to find the satisfactory individuals, and also apply our algorithm to a fashion evolutionary design system to demonstrate its efficiency.
基金supported by the National Natural Science Foundation of China(61302145)
文摘This paper improves the resampling step of particle filtering（PF） based on a broad interactive genetic algorithm to resolve particle degeneration and particle shortage.For target tracking in image processing,this paper uses the information coming from the particles of the previous fame image and new observation data to self-adaptively determine the selecting range of particles in current fame image.The improved selecting operator with jam gene is used to ensure the diversity of particles in mathematics,and the absolute arithmetical crossing operator whose feasible solution space being close about crossing operation,and non-uniform mutation operator is used to capture all kinds of mutation in this paper.The result of simulating experiment shows that the algorithm of this paper has better iterative estimating capability than extended Kalman filtering（EKF）,PF,regularized partide filtering（RPF）,and genetic algorithm（GA）-PF.
基金supported by the National Natural Science Foundation of China (No. 30771113,30870810)the Program for New Century Excellent Talents in University
文摘Objective To investigate the interaction between the genes required for the functions of AWA olfactory neuron and insulin/IGF signaling in regulating the longevity of nematode Caenorhabditis elegans （C. elegans）. Methods The mutants that had loss-of-function mutation of the genes required for AWA, AWC, ASE, and AFD sensory neurons were employed. Lifespan, the speed of pharynx pumping, the intestinal autofluorescence, the dauer formation, and the brood size were examined. Rescue experiments were performed to confrm the role of the genes required for the functions of AWA neuron in regulating lifespan. Moreover, genetic interactions between genes required for the functions of AWA neuron and insulin/ IGF signaling were investigated. Results Mutations of odr-7, odr-2, and odr-3 genes required for the functions of AWA neuron significantly increased the mean lifespan of nematodes and slowed the accumulation of intestinal autofluorescence. Besides, these mutations were closely associated with higher pumping rates during aging. However, mutation of odr-7, odr- 2, or odr-3 did not obviously affect the brood size or the dauer formation, and the regulation of longevity by odr-7, odr-2, and odr-3 was temperature-independent. In contrast, mutations of genes required for the functions of ASE, AWC, and AFD sensory neurons did not infuence the nematode lifespan. Moreover, expression of odr-7, odr-2 and odr-3 in AWA neuron could completely or largely restore the altered lifespan in odr-7, odr-2 and odr-3 mutants. Furthermore, genetic interaction assay demonstrated that the extended lifespan in odr-7 mutant could be suppressed by daf-16 mutation and enhanced by daf- 2 or age-1 mutation, whereas mev-1 and pha-4 were not required for the long lifespan of odr-7 mutant. Conclusion The genes required for the function of AWA sensory neuron could regulate the nematode longevity in an insulin/IGF signaling-dependent fashion in C. elegans.
基金This work was supported by the National Natural Science Foundation of China(31971914)the National Key Research and Development Program of China(2016YFD0100501)+3 种基金the Key Research and Development Program of Jiangsu Province,China(BE2018357)the Science Fund for Distinguished Young Scholars of Jiangsu Province,China(BK20200045)the Jiangsu Agricultural Science and Technology Innovation Fund(CX(18)1001)the Jiangsu PAPD Talent Project,and the Yong Elite Scientists Sponsorship Program by China Association for Science and Technology(2018QNRC001).
文摘The panicle architecture and grain size of rice affect not only grain yield but also grain quality,especially grain appearance.The erect-panicle(EP)trait controlled by the qpe9-1/dep1 allele has been widely used in high-yielding japonica rice breeding,but usually accompanied with moderate appearance of milled rice.The null gs9 allele shows a good potential for improving grain shape and appearance.However,GS9 and qPE9-1/DEP1 loci are tightly linked,and their interaction is unclear,which obviously restricts their utilization in modern rice breeding.In the present study,comparative analyses of protein and mRNA levels revealed that GS9 and qPE9-1 function independently.Three nearisogenic lines(NILs)carrying various allelic combinations of these two loci,NIL(gs9/qpe9-1),NIL(GS9/qPE9-1)and NIL(gs9/qPE9-1),in the EP japonica cultivar 2661(GS9/qpe9-1)background were developed for genetic interaction analysis.GS9 and qPE9-1 had additive effects on determining grain size,and the null gs9 allele could decrease grain chalkiness and improve grain appearance without affecting plant and panicle architecture in EP japonica cultivars.Additionally,introgression lines(ILs)developed in another released EP japonica cultivar Wuyujing 27(WYJ27)background showed the same additive effect and the feasibility of utilizing the gs9 allele to improve grain appearance quality in high-yielding EP cultivars.This study provides an effective strategy for rice breeders to improve rice grain appearance in EP japonica and related cultivars.
文摘With the cultural myth that science can only determine the way the world ＂is＂ （facts）, while humanities, social sciences, lawyers, philosophers, and theologians must determine the way the world ＂ought to be＂ （values）, those in position of global-, national-, and local-political power make major decisions of the use （or non-use） of scientific knowledge and technology. As a result, the human being has created a non-scientifically based cultural environment that is affecting his ability to survive. In effect, cultural evolution is occurring more rapidly than biological evolution that can adapt to the changes brought about in the physical and psycho-social environments. In a pluralistic cultural world, where each society has generated a different view of human nature and different ethical values, the use, misuse, or non-use of scientific and technological advances are derived from these unscientific views of human nature. Since all life depends on limiting interacting environmental and ecological factors, it is imperative that scientific information be used to govern how to minimize irreversible effects on life-sustaining ecological factors, but also scientific information bearing on understanding human nature ought to be integrated into a ＂global bioethics＂. While ethical values cannot be directly derived from scientific factors, it is also true that human values or our ＂ought＂ cannot be maintained in ignorance or defiance of the facts or the ＂is＂.
基金This work was supported by funds from the National Natural Science Foundation of China （31230051 31110103915）+6 种基金 National Key Basic Research Developments Program, Ministry of Science and Technology, China （2013CB126902） 863 Hitech Project, Ministry of Science and Technology,China （2011AA10A101 2012AA10A302） the Science and Technology Commission of Shanghai Municipality （10JC1406400 10DZ2294100 11JC1404900） and National Transgenic Major Program （2011ZX08009-003-003）. Ludovico Dreni is supported by the BIOGESTECA program financed by the Lombardy region.The authors gratefully acknowledge Drs Hajime Sakai and Yasuo Nagato for providing spwl-1, Dr Venkatesan Sundaresan for providing osmads58, Zhijing Luo and Mingjiao Chen for mutant screening and generation, and Alessandro Merisio for the assistance in in situ analysis. No conflict of interest declared.
文摘Rice （Oryza sativa） has unique floral patterns that contribute to grain yield. However, the molecular mechanism underlying the specification of floral organ identities in rice, particularly the interaction among floral homeotic genes, remains poorly understood. Here, we show that the floral homeotic gene OsMADS16 （also called SUPERWOMAN1, SPWl, a B-class gene） acts together with the rice C-class genes OsMADS3 and OsMADS58 in specifying floral organ patterning. OsMADS16 and the two C-class genes have an overlapping expression pattern in the third whorl founder cells. Compared with the single mutants, both spwl-1 osmads3-4 and spwl-1 osmads58 double mutants exhibit additional whorls of glume-like organs within the flower, particularly an extra whorl of six glume-like structures formed at the position of the wild-type stamens. These ectopic glume-like structures were shown to have palea identity through cellular observation and in situ hybridization analysis using marker genes. Our results suggest that B- and C-class genes play a key role in suppressing indeterminate growth within the floral meristem, particularly whorl-3 primordia. We also hypothesize that, in contrast to previous assumptions, the specialized spikelet organ in rice, the palea, is the counterpart of the sepal in eudicots, and the lemma is homologous to the bract.
