查看更多>>摘要：Fleshy fruits become more susceptible to pathogen infection when they ripen;for example,changes in cell wall properties related to softening make it easier for pathogens to infect fruits.The need for high-quality fruit has driven extensive research on improving pathogen resistance in important fruit crops such as tomato(Solanum lycopersicum).In this review,we summarize current progress in un-derstanding how changes in fruit properties during ripening affect infection by pathogens.These changes affect physical barriers that limit pathogen entry,such as the fruit epidermis and its cuticle,along with other defenses that limit pathogen growth,such as preformed and induced defense compounds.The plant immune system also pro-tects ripening fruit by recognizing pathogens and initiating defense responses involving reactive oxygen species production,mitogen-activated protein kinase signaling cascades,and jasmonic acid,salicylic acid,ethylene,and abscisic acid signaling.These phytohormones regulate an in-tricate web of transcription factors(TFs)that activate resistance mechanisms,including the expression of pathogenesis-related genes.In tomato,ripening regulators,such as RIPENING INHIBITOR and NON_RIPENING,not only regu-late ripening but also influence fruit defenses against pathogens.Moreover,members of the ETHYLENE RESPONSE FACTOR(ERF)family play pivotal and distinct roles in ripening and defense,with different members being regulated by different phytohormones.We also discuss the interaction of ripening-related and defense-related TFs with the Mediator transcription complex.As the ripening processes in climac-teric and non-climacteric fruits share many sim-ilarities,these processes have broad applica-tions across fruiting crops.Further research on the individual contributions of ERFs and other TFs will inform efforts to diminish disease sus-ceptibility in ripe fruit,satisfy the growing de-mand for high-quality fruit and decrease food waste and related economic losses.
查看更多>>摘要：Prime editing is a versatile CRISPR/Cas-based pre-cise genome-editing technique for crop breeding.Four new types of prime editors(PEs)named PE6a-d were recently generated using evolved and engineered reverse transcriptase(RT)variants from three different sources.In this study,we tested the editing efficiencies of four PE6 variants and two additional PE6 constructs with double-RT modules in transgenic rice(Oryza sativa)plants.PE6c,with an evolved and engineered RT variant from the yeast Tf1 retrotransposon,yielded the highest prime-editing efficiency.The average fold change in the editing efficiency of PE6c compared with PEmax exceeded 3.5 across 18 agronomically important target sites from 15 genes.We also demonstrated the feasibility of using two RT modules to improve prime-editing efficiency.Our results suggest that PE6c or its derivatives would be an excellent choice for prime editing in monocot plants.In addition,our findings have laid a foundation for prime-editing-based breeding of rice varieties with enhanced agronomically important traits.
查看更多>>摘要：Soil salinity is a worldwide problem threatening crop yields.Some plant growth-promoting rhizo-bacteria(PGPR)could survive in high salt envi-ronment and assist plant adaptation to stress.Nevertheless,the genomic and metabolic fea-tures,as well as the regulatory mechanisms pro-moting salt tolerance in plants by these bacteria remain largely unknown.In the current work,a novel halotolerant PGPR strain,namely,Bacillus sp.strain RA can enhance tomato tolerance to salt stress.Comparative genomic analysis of strain RA with its closely related species indicated a high level of evolutionary plasticity exhibited by strain-specific genes and evolutionary constraints driven by purifying selection,which facilitated its ge-nomic adaptation to salt-affected soils.The tran-scriptome further showed that strain RA could tolerate salt stress by balancing energy metabo-lism via the reprogramming of biosynthetic path-ways.Plants exude a plethora of metabolites that can strongly influence plant fitness.The accumu-lation of myo-inositol in leaves under salt stress was observed,leading to the promotion of plant growth triggered by Bacillus sp.strain RA.Im-portantly,myo-inositol serves as a selective force in the assembly of the phyllosphere microbiome and the recruitment of plant-beneficial species.It promotes destabilizing properties in phyllosphere bacterial co-occurrence networks,but not in fungal networks.Furthermore,interdomain interactions between bacteria and fungi were strengthened by myo-inositol in response to salt stress.This work highlights the genetic adaptation of RA to salt-affected soils and its ability to impact phyllosphere microorganisms through the adjustment of myo-inositol metabolites,thereby imparting enduring resistance against salt stress in tomato.
查看更多>>摘要：Light and gravity coordinately regulate the direc-tional growth of plants.Arabidopsis Gravitropic in the Light 1(GIL1)inhibits the negative gravi-tropism of hypocotyls in red and far-red light,but the underlying molecular mechanisms remain elusive.Our study found that GIL1 is a plasma membrane-localized protein.In endodermal cells of the upper part of hypocotyls,GIL1 controls the negative gravitropism of hypocotyls.GIL1 directly interacts with PIN3 and inhibits the auxin transport activity of PIN3.Mutation of PIN3 suppresses the abnormal gravitropic response of gil1 mutant.The GIL1 protein is unstable in darkness but it is sta-bilized by red and far-red light.Together,our data suggest that light-stabilized GIL1 inhibits the negative gravitropism of hypocotyls by sup-pressing the activity of the auxin transporter PIN3,thereby enhancing the emergence of young seedlings from the soil.
查看更多>>摘要：Although the cell membrane and cytoskeleton play essential roles in cellular morphogenesis,the inter-action between the membrane and cytoskeleton is poorly understood.Cotton fibers are extremely elongated single cells,which makes them an ideal model for studying cell development.Here,we used the sphingolipid biosynthesis inhibitor,fumonisin B1(FB1),and found that it effectively suppressed the myeloblastosis(MYB)transcription factor GhMYB86,thereby negatively affecting fiber elongation.A direct target of GhMYB86 is GhTUB7,which encodes the tubulin protein,the major component of the micro-tubule cytoskeleton.Interestingly,both the over-expression of GhMYB86 and GhTUB7 caused an ectopic microtubule arrangement at the fiber tips,and then leading to shortened fibers.Moreover,we found that GhMBE2 interacted with GhMYB86 and that FB1 and reactive oxygen species induced its transport into the nucleus,thereby enhancing the promotion of GhTUB7 by GhMYB86.Overall,we established a GhMBE2-GhMYB86-GhTUB7 regu-lation module for fiber elongation and revealed that membrane sphingolipids affect fiber elongation by altering microtubule arrangement.
查看更多>>摘要：Although green light(GL)is located in the middle of the visible light spectrum and regulates a series of plant developmental processes,the mechanism by which it regulates seedling development is largely unknown.In this study,we demonstrated that GL promotes atypical photomorphogenesis in Arabidopsis thaliana via the dual regulations of phytochrome B(phyB)and phyA.Although the Pr-to-Pfr conversion rates of phyB and phyA under GL were lower than those under red light(RL)in a fluence rate-dependent and time-dependent manner,long-term treatment with GL induced high Pfr/Pr ratios of phyB and phyA.Moreover,GL induced the formation of numerous small phyB photobodies in the nucleus,resulting in atypical photomorphogenesis,with smaller cotyledon opening angles and longer hypocotyls in seed-lings compared to RL.The abundance of phyA significantly decreased after short-and long-term GL treatments.We determined that four major PHYTOCHROME-INTERACTING FACTORs(PIFs:PIF1,PIF3,PIF4,and PIF5)act downstream of phyB in GL-mediated cotyledon opening.In addi-tion,GL plays opposite roles in regulating different PIFs.For example,under continuous GL,the protein levels of all PIFs decreased,whereas the transcript levels of PIF4 and PIF5 strongly increased compared with dark treatment.Taken together,our work provides a detailed molecular framework for understanding the role of the antagonistic regulations of phyB and phyA in GL-mediated atypical photomorphogenesis.
查看更多>>摘要：Light is one of the most essential environmental factors that tightly and precisely control various physiological and developmental processes in plants.B-box CONTAINING PROTEINs(BBXs)play central roles in the regulation of light-dependent development.In this study,we report that BBX9 is a positive regulator of light signaling.BBX9 interacts with the red light photoreceptor PHYTOCHROME B(phyB)and transcription fac-tors PHYTOCHROME-INTERACTING FACTORs(PIFs).phyB promotes the stabilization of BBX9 in light,while BBX9 inhibits the transcriptional acti-vation activity of PIFs.In turn,PIFs directly bind to the promoter of BBX9 to repress its transcription.On the other hand,BBX9 associates with the positive regulator of light signaling,BBX21,and enhances its biochemical activity.BBX21 asso-ciates with the promoter regions of BBX9 and transcriptionally up-regulates its expression.Col-lectively,this study unveiled that BBX9 forms a negative feedback loop with PIFs and a positive one with BBX21 to ensure that plants adapt to fluctuating light conditions.
查看更多>>摘要：IDEAL PLANT ARCHITECTURE1(IPA1)is a pivotal gene controlling plant architecture and grain yield.However,little is known about the effects of Triticum aestivum SQUAMOSA PROMOTER-BINDING-LIKE 14(TaSPL14),an IPA1 ortholog in wheat,on balancing yield traits and its regulatory mechanism in wheat(T.aestivum L.).Here,we determined that the T.aestivum GRAIN WIDTH2(TaGW2)-TaSPL14 module influences the balance between tiller number and grain weight in wheat.Overexpression of TaSPL14 resulted in a reduced tiller number and increased grain weight,whereas its knockout had the opposite effect,indicating that TaSPL14 negatively regulates tillering while positively regulating grain weight.We further identified TaGW2 as a novel interacting protein of TaSPL14 and confirmed its ability to mediate the ubiquitination and degradation of TaSPL14.Based on our genetic evidence,TaGW2 acts as a positive regulator of tiller number,in addition to its known role as a negative regulator of grain weight,which is opposite to TaSPL14.Moreover,combinations of TaSPL14-7A and TaGW2-6A haplotypes exhibit significantly additive effects on tiller number and grain weight in wheat breeding.Our findings pro-vide insight into how the TaGW2-TaSPL14 module regulates the trade-off between tiller number and grain weight and its potential application in improving wheat yield.
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