查看更多>>摘要：Maize is a major staple crop widely used as food,animal feed,and raw materials in in-dustrial production.High-density planting is a major factor contributing to the continuous in-crease of maize yield.However,high planting density usually triggers a shade avoidance response and causes increased plant height and ear height,resulting in lodging and yield loss.Reduced plant height and ear height,more erect leaf angle,reduced tassel branch number,earlier flowering,and strong root system ar-chitecture are five key morphological traits re-quired for maize adaption to high-density planting.In this review,we summarize recent advances in deciphering the genetic and mo-lecular mechanisms of maize involved in re-sponse to high-density planting.We also dis-cuss some strategies for breeding advanced maize cultivars with superior performance under high-density planting conditions.
查看更多>>摘要：Coordinated morphogenic adaptation of growing plants is critical for their survival and propagation under fluctuating environments.Plant morphogenic responses to light and warm temperatures,termed photomorphogenesis and thermomorphogenesis,respectively,have been extensively studied in recent decades.During photomorphogenesis,plants actively reshape their growth and developmental pat-terns to cope with changes in light regimes.Accordingly,photomorphogenesis is closely associated with diverse growth hormonal cues.Notably,accumulating evidence indicates that light-directed morphogenesis is profoundly affected by two recently identified phytochem-icals,karrikins(KARs)and strigolactones(SLs).KARs and SLs are structurally related butenolides acting as signaling molecules during a variety of developmental steps,in-cluding seed germination.Their receptors and signaling mediators have been identified,and associated working mechanisms have been explored using gene-deficient mutants in various plant species.Of particular interest is that the KAR and SL signaling pathways play important roles in environmental responses,among which their linkages with photo-morphogenesis are most comprehensively studied during seedling establishment.In this review,we focus on how the phytochemical and light signals converge on the optimization of morphogenic fitness.We also discuss molec-ular mechanisms underlying the signaling crosstalks with an aim of developing potential ways to improve crop productivity under cli-mate changes.
查看更多>>摘要：Photoreceptor cryptochromes(CRYs)mediate blue-light regulation of plant growth and development.It has been reported that Arabidopsis CRY1and CRY2 function by physically interacting with at least 84 proteins,including transcription factors or co-factors,chromatin regulators,splicing factors,messenger RNA methyltransferases,DNA repair proteins,E3 ubiquitin ligases,protein kinases and so on.Of these 84 proteins,47 have been reported to exhibit altered binding affinity to CRYs in response to blue light,and 41 have been shown to exhibit condensation to CRY photobodies.The blue light-regulated composition or condensation of CRY complexes results in changes of gene expression and developmental programs.In this mini-review,we analyzed recent studies of the photoregulatory mechanisms of Arabidopsis CRY complexes and proposed the dual mechanisms of action,including the"Lock-and-Key"and the"Liquid-Liquid Phase Separation(LLPS)"mechanisms.The dual CRY ac-tion mechanisms explain,at least partially,the structural diversity of CRY-interacting proteins and the functional diversity of the CRY photoreceptors.
查看更多>>摘要：The phytohormone jasmonate(JA)coordinates stress and growth responses to increase plant survival in unfavorable environments.Although JA can enhance plant UV-B stress tolerance,the mechanisms underlying the interaction of UV-B and JA in this response remain unknown.In this study,we demonstrate that the UV RESISTANCE LOCUS 8-TEOSINTE BRANCHED1,Cycloidea and PCF 4-LIPOXYGENASE2(UVR8-TCP4-LOX2)module regulates UV-B tolerance dependent on JA signaling pathway in Arabidopsis thaliana.We show that the nucleus-localized UVR8 physically interacts with TCP4 to increase the DNA-binding activity of TCP4 and upregulate the JA biosyn-thesis gene LOX2.Furthermore,UVR8 activates the expression of LOX2 in a TCP4-dependent manner.Our genetic analysis also provides evi-dence that TCP4 acts downstream of UVR8 and upstream of LOX2 to mediate plant responses to UV-B stress.Our results illustrate that the UV-B-dependent interaction of UVR8 and TCP4 serves as an important UVR8-TCP4-LOX2 module,which integrates UV-B radiation and JA signaling and represents a new UVR8 signaling mechanism in plants.
查看更多>>摘要：Transcriptional regulation plays a key role in the control of seed dormancy,and many transcription factors(TFs)have been documented.However,the mechanisms underlying the interactions between different TFs within a transcriptional complex regu-lating seed dormancy remain largely unknown.Here,we showed that TF PHYTOCHROME-INTERACTING FACTOR4(PIF4)physically interacted with the ab-scisic acid(ABA)signaling responsive TF ABSCISIC ACID INSENSITIVE4(ABI4)to act as a transcriptional complex to promote ABA biosynthesis and signaling,finally deepening primary seed dormancy.Both pif4 and abi4 single mutants exhibited a decreased pri-mary seed dormancy phenotype,with a synergistic effect in the pif4/abi4 double mutant.PIF4 binds to ABI4 to form a heterodimer,and ABI4 stabilizes PIF4 at the protein level,whereas PIF4 does not affect the protein stabilization of ABI4.Subsequently,both TFs independently and synergistically promoted the ex-pression of ABI4 and NCED6,a key gene for ABA anabolism.The genetic evidence is also consistent with the phenotypic,physiological and biochemical analysis results.Altogether,this study revealed a transcriptional regulatory cascade in which the PIF4-ABI4 transcriptional activator complex synerg-istically enhanced seed dormancy by facilitating ABA biosynthesis and signaling.
查看更多>>摘要：Precise responses to changes in light quality are crucial for plant growth and development.For ex-ample,hypocotyls of shade-avoiding plants typically elongate under shade conditions.Although this typical shade-avoidance response(TSR)has been studied in Arabidopsis(Arabidopsis thaliana),the molecular mechanisms underlying shade tolerance are poorly understood.Here we report that B.napus(Brassica napus)seedlings exhibit dual shade re-sponses.In addition to the TSR,B.napus seedlings also display an atypical shade response(ASR),with shorter hypocotyls upon perception of early-shade cues.Genome-wide selective sweep analysis in-dicated that ASR is associated with light and auxin signaling.Moreover,genetic studies demonstrated that phytochrome A(BnphyA)promotes ASR,whereas BnphyB inhibits it.During ASR,YUCCA8 expression is activated by early-shade cues,leading to increased auxin biosynthesis.This inhibits hypo-cotyl elongation,as young B.napus seedlings are highly sensitive to auxin.Notably,two non-canonical AUXIN/INDOLE-3-ACETIC ACID(Aux/IAA)repressor genes,BnIAA32 and BnIAA34,are expressed during this early stage.BnIAA32 and BnIAA34 inhibit hypocotyl elongation under shade conditions,and mutations in BnIAA32 and BnIAA34 suppress ASR.Collectively,our study demonstrates that the temporal expression of BnIAA32 and BnIAA34 determines the behavior of B.napus seedlings fol-lowing shade-induced auxin biosynthesis.
查看更多>>摘要：Maize(Zea mays subspecies mays)is an important commercial crop across the world,and its flowering time is closely related to grain yield,plant cycle and latitude adaptation.FKF1 is an essential clock-regulated blue-light receptor with distinct functions on flowering time in plants,and its function in maize remains unclear.In this study,we identified two FKF1 homologs in the maize genome,named ZmFKF1a and ZmFKF1b,and indicated that ZmFKF1a and ZmFKF1b independently regulate reproductive transition through interacting with ZmCONZ1 and ZmGI1 to increase the transcription levels of ZmCONZ1 and ZCN8.We demonstrated that ZmFKF1b underwent artificial selection during modem breeding in China probably due to its role in geographical adaptation.Furthermore,our data suggested that ZmFKF1bHap-C7 may be an elite al-lele,which increases the abundance of ZmCONZ1 mRNA more efficiently and adapt to a wider range of temperature zone than that of ZmFKF1bHap_Z58 to promote maize floral transition.It extends our understanding of the genetic diversity of maize flowering.This allele is expected to be introduced into tropical maize germplasm to enrich breeding resources and may improve the adaptability of maize at different climate zones,especially at tem-perate region.
查看更多>>摘要：Plants deploy versatile scaffold proteins to intricately modulate complex cell signaling.Among these,RACK1A(Receptors for Activated C Kinase 1A)stands out as a multifaceted scaffold protein func-tioning as a central integrative hub for diverse sig-naling pathways.However,the precise mechanisms by which RACK1A orchestrates signal transduction to optimize seedling development remain largely unclear.Here,we demonstrate that RACK1A facilitates hypocotyl elongation by functioning as a flexible platform that connects multiple key compo-nents of light signaling pathways.RACK1A interacts with PHYTOCHROME INTERACTING FACTOR(PIF)3,enhances PIF3 binding to the promoter of BBX11 and down-regulates its transcription.Furthermore,RACK1A associates with ELONGATED HYPOCOTYL 5(HY5)to repress HY5 biochemical activity toward target genes,ultimately contributing to hypocotyl elongation.In darkness,RACK1A is targeted by CONSTITUTIVELY PHOTOMORPHOGENIC(COP)1 upon phosphorylation and subjected to COP1-mediated degradation via the 26 S proteasome system.Our findings provide new insights into how plants utilize scaffold proteins to regulate hypocotyl elongation,ensuring proper skoto-and photo-morphogenic development.
查看更多>>摘要：Starch is a major storage carbohydrate in plants and is critical in crop yield and quality.Starch synthesis is intricately regulated by internal meta-bolic processes and external environmental cues;however,the precise molecular mechanisms gov-eming this process remain largely unknown.In this study,we revealed that high red to far-red(high R:FR)light significantly induces the synthesis of leaf starch and the expression of synthesis-related genes,whereas low R:FR light suppress these processes.Arabidopsis phytochrome B(phyB),the primary R and FR photoreceptor,was identified as a critical positive regulator in this process.Down-stream of phyB,basic leucine zipper transcription factor ELONGATED HYPOCOTYL5(HY5)was found to enhance starch synthesis,whereas the basic helix-loop-helix transcription factors PHY-TOCHROME INTERACTING FACTORs(PIF3,PIF4,and PIF5)inhibit starch synthesis in Arabidopsis leaves.Notably,HY5 and PIFs directly compete for binding to a shared G-box cis-element in the pro-moter region of genes encoding starch synthases GBSS,SS3,and SS4,which leads to antagonistic regulation of their expression and,consequently,starch synthesis.Our findings highlight the vital role of phyB in enhancing starch synthesis by stabilizing HY5 and facilitating PIFs degradation under high R:FR light conditions.Conversely,under low R:FR light,PIFs predominantly inhibit starch synthesis.This study provides insight into the physiological and molecular functions of phyB and its downstream transcription factors HY5 and PIFs in starch synthesis regulation,shedding light on the regulatory mechanism by which plants synchronize dynamic light signals with metabolic cues to module starch synthesis.
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