查看更多>>摘要：Biotic and abiotic stresses can severely limit crop productivity.In response to drought,plants close stomata to prevent water loss.Furthermore,stomata are the main entry point for several pathogens.Therefore,the development of natural products to control stomata closure can be considered a sustainable strategy to cope with stresses in agriculture.Plants respond to different stresses by releasing volatile organic compounds.Green leaf volatiles,which are commonly produced across different plant species after tissue damage,comprise an important group within volatile organic compounds.Among them,(Z)-3-hexenyl butyrate(HB)was described as a natural inducer of stomatal closure,playing an important role in stomatal immunity,although its mechanism of action is still unknown.Through different genetic,pharmacological,and biochemical approaches,we here uncover that HB perception initiates various defence signalling events,such as activation of Ca2+permeable channels,mitogen-activated protein kinases,and production of Nicotinamide adenine dinucleotide phosphate(NADPH)oxidase-mediated reactive oxygen species.Furthermore,HB-mediated stomata closure was found to be independent of abscisic acid biosynthesis and signalling.Additionally,exogenous treatments with HB alleviate water stress and improve fruit productivity in tomato plants.The efficacy of HB was also tested under open field conditions,leading to enhanced resistance against Phytophthora spp.and Pseudomonas syringae infection in potato and tomato plants,respectively.Taken together,our results provide insights into the HB signalling transduction pathway,confirming its role in stomatal closure and plant immune system activation,and propose HB as a new phytoprotectant for the sustainable control of biotic and abiotic stresses in agriculture.
查看更多>>摘要：Vacuole largely dictates the fruit taste and flavor,as most of the sugars and organic acids are stored in the vacuoles of the fruit.However,difficulties associated with vacuole separation severely hinder identification and characterization of vacuolar proteins in fruit species.In this study,we established an effective approach for separating vacuoles and successfully purified vacuolar protein from six types of citrus fruit with varying patterns of sugar and organic acid contents.By using label-free LC-MS/MS proteomic analysis,1443 core proteins were found to be associated with the essential functions of vacuole in citrus fruit.Correlation analysis of metabolite concentration with proteomic data revealed a transporter system for the accumulation of organic acid and soluble sugars in citrus.Furthermore,we characterized the physiological roles of selected key tonoplast transporters,ABCG15,Dict2.1,TMT2,and STP7 in the accumulation of citric acid and sugars.These findings provide a novel perspective and practical solution for investigating the transporters underlying the formation of citrus taste and flavor.
查看更多>>摘要：Cytosine and adenosine base editors(CBE and ABE)have been widely used in plants,greatly accelerating gene function research and crop breeding.Current base editors can achieve efficient A-to-G and C-to-T/G/A editing.However,efficient and heritable A-to-Y(A-to-T/C)editing remains to be developed in plants.In this study,a series of A-to-K base editor(AKBE)systems were constructed for monocot and dicot plants.Furthermore,nSpCas9 was replaced with the PAM-less Cas9 variant(nSpRY)to expand the target range of the AKBEs.Analysis of 228 T0 rice plants and 121 T0 tomato plants edited using AKBEs at 18 endogenous loci revealed that,in addition to highly efficient A-to-G substitution(41.0％on average),the plant AKBEs can achieve A-to-T conversion with efficiencies of up to 25.9 and 10.5％in rice and tomato,respectively.Moreover,the rice-optimized AKBE generates A-to-C conversion in rice,with an average efficiency of 1.8％,revealing the significant value of plant-optimized AKBE in creating genetic diversity.Although most of the A-to-T and A-to-C edits were chimeric,desired editing types could be transmitted to the T1 offspring,similar to the edits generated by the traditional ABE8e.Besides,using AKBEs to target tyrosine(Y,TAT)or cysteine(C,TGT)achieved the introduction of an early stop codon(TAG/TAA/TGA)of target genes,demonstrating its potential use in gene disruption.
查看更多>>摘要：Botrytis cinerea is one of the most destructive pathogens in strawberry cultivation.Successful infection by B.cinerea requires releasing a large number of effectors that interfere with the plant's immune system.One of the effectors required by B.cinerea for optimal virulence is the secreted protein BcXYG1,which is thought to associate with proteins near the plasma membrane of the host plant to induce necrosis.However,the host proteins that associate with BcXYG1 at the plasma membrane are currently unknown.We found that BcXYG1 binds to FvBPL4 and FvACD11 at the plasma membrane.Both FvBPL4 and FvACD11 are negative regulators of plant immunity in strawberry.Our results demonstrate that degradation of FvBPL4by BcXYG1 promotes disease resistance while stabilization of FvACD11 by BcXYG1 suppresses the immune response.These findings suggest that BcXYG1 suppresses plant immunity and promotes B.cinerea infection by regulating FvBPL4 and FvACD11 protein levels.
查看更多>>摘要：The genetic and epigenetic mechanisms underlying the coexistence and coordination of the four diverged subgenomes(ABCD)in octoploid strawberries(Fragaria × ananassa)remains poorly understood.In this study,we have assembled a haplotype-phased gap-free octoploid genome for the strawberry,which allowed us to uncover the sequence,structure,and epigenetic divergences among the subgenomes.The diploid progenitors of the octoploid strawberry,apart from subgenome A(Fragaria vesca),have been a subject of public controversy.Phylogenomic analyses revealed a close relationship between diploid species Fragaria iinumae and subgenomes B,C,and D.Subgenome A,closely related to F.vesca,retains the highest number of genes,exhibits the lowest content of transposable elements(TEs),experiences the strongest purifying selection,shows the lowest DNA methylation levels,and displays the highest expression level compared to the other three subgenomes.Transcriptome and DNA methylome analyses revealed that subgenome A-biased genes were enriched in fruit development biological processes.In contrast,although subgenomes B,C,and D contain equivalent amounts of repetitive sequences,they exhibit diverged methylation levels,particularly for TEs located near genes.Taken together,our findings provide valuable insights into the evolutionary patterns of subgenome structure,divergence and epigenetic dynamics in octoploid strawberries,which could be utilized in strawberry genetics and breeding research.
查看更多>>摘要：Nitrogen(N)and potassium(K)are two important mineral nutrients in regulating leaf photosynthesis.However,the influence of N and K interaction on photosynthesis is still not fully understood.Using a hydroponics approach,we studied the effects of different N and K conditions on the physiological characteristics,N allocation and photosynthetic capacity of apple rootstock M9T337.The results showed that high N and low K conditions significantly reduced K content in roots and leaves,resulting in N/K imbalance,and allocated more N in leaves to non-photosynthetic N.Low K conditions increased biochemical limitation(BL),mesophyll limitation(MCL),and stomatal limitation(SL).By setting different N supplies,lowering N levels under low K conditions increased the proportion of water-soluble protein N(Nw)and sodium dodecyl sulfate-soluble proteins(Ns)by balancing N/K and increased the proportion of carboxylation N and electron transfer N.This increased the maximum carboxylation rate and mesophyll conductance,which reduced MCL and BL and alleviated the low K limitation of photosynthesis in apple rootstocks.In general,our results provide new insights into the regulation of photosynthetic capacity by N/K balance,which is conducive to the coordinated supply of N and K nutrients.
查看更多>>摘要：Gray mold caused by Botrytis cinerea is one of the major threats in lily production.However,limited information is available about the underlying defense mechanism against B.cinerea in lily.Here,we characterized a nuclear-localized class A heat stress transcription factor(HSF)-LlHSFA4 from lily(Lilium longiflorum),which positively regulated the response to B.cinerea infection.LlHSFA4 transcript and its promoter activity were increased by B.cinerea infection in lily,indicating its involvement in the response to B.cinerea.Virus-induced gene silencing(VIGS)of LlHSFA4 impaired the resistance of lily to B.cinerea.Consistent with its role in lily,overexpression of LlHSFA4 in Arabidopsis(Arabidopsis thaliana)enhanced the resistance of transgenic Arabidopsis to B.cinerea infection.Further analysis showed that LlWRKY33 directly activated LlHSFA4 expression.We also found that both LlHSFA4 and LlWRKY33 positively regulated plant response to B.cinerea through reducing cell death and H2O2 accumulation and activating the expression of the reactive oxygen species(ROS)scavenging enzyme gene LlCAT2(Catalase 2)by binding its prompter,which might contribute to reducing H2O2 accumulation in the infected area.Taken together,our data suggested that there may be a LlWRKY33-LlHSFA4-LlCAT2 regulatory module which confers B.cinerea resistance via reducing cell death and the ROS accumulation.
查看更多>>摘要：Populus cathayana Rehder,an indigenous poplar species of ecological and economic importance,is widely distributed in a high-elevation range from southwest to northeast China.Further development of this species as a sustainable poplar resource has been hindered by a lack of genome information the at the population level.Here,we produced a chromosome-level genome assembly of P.cathayana,covering 406.55 Mb(scaffold N50=20.86 Mb)and consisting of 19 chromosomes,with 35 977 protein-coding genes.Subsequently,we made a genomic variation atlas of 438 wild individuals covering 36 representative geographic areas of P.cathayana,which were divided into four geographic groups.It was inferred that the Northwest China regions served as the genetic diversity centers and a population bottleneck happened during the history of P.cathayana.By genotype-environment association analysis,947 environment-association loci were significantly associated with temperature,solar radiation,precipitation,and altitude variables.We identified local adaptation genes involved in DNA repair and UV radiation response,among which UVR8,HY5,and CUL4 had key roles in high-altitude adaptation of P.cathayana.Predictions of adaptive potential under future climate conditions showed that P.cathayana populations in areas with drastic climate change were anticipated to have greater maladaptation risk.These results provide comprehensive insights for understanding wild poplar evolution and optimizing adaptive potential in molecular breeding.
查看更多>>摘要：Podosphaera xanthii is the main causal agent of powdery mildew(PM)on Cucurbitaceae.In Cucumis melo,the Pm-w resistance gene,which confers resistance to P.xanthii,is located on chromosome 5 in a cluster of nucleotide-binding leucine-rich repeat receptors(NLRs).We used positional cloning and transgenesis,to isolate the Pm-wWMR29 gene encoding a coiled-coil NLR(CC-NLR).Pm-wWMR29 conferred high level of resistance to race 1 of PM and intermediate level of resistance to race 3 of PM.Pm-wWMR 29 turned out to be a homolog of the Aphis gossypii resistance gene Vat-1PI 161375.We confirmed that Pm-wWMR29 did not confer resistance to aphids,while Vat-1PI 161375 did not confer resistance to PM.We showed that both homologs were included in a highly diversified cluster of NLRs,the Vat cluster.Specific Vat-1PI 161375 and Pm-wWMR 29 markers were present in 10％to 13％of 678 accessions representative of wild and cultivated melon types worldwide.Phylogenic reconstruction of 34 protein homologs of Vat-1PI 161375 and Pm-wWMR 29 identified in 24 melon accessions revealed an ancestor with four R65aa—a specific motif in the LRR domain,evolved towards aphid and virus resistance,while an ancestor with five R65aa evolved towards PM resistance.The complexity of the cluster comprising the Vat/Pm-w genes and its diversity in melon suggest that Vat homologs may contribute to the recognition of a broad range of yet to be identified pests and pathogens.
查看更多>>摘要：A high-quality reference genome is indispensable for resolving biologically essential traits.Ficus hispida is a dioecious plant.A complete Ficus reference genome will be crucial for understanding their sex evolution and important biological characteristics,such as aerial roots,mutualistic symbiosis with ficus-wasps,and fruiting from old stems.Here,we generated a telomere-to-telomere(T2T)genome for F.hispida using PacBio HiFi and Oxford Nanopore Ultra-long sequencing technologies.The genome contiguity and completeness has shown improvement compared with the previously released genome,with the annotation of six centromeres and 28 telomeres.We have refined our previously reported 2-Mb male-specific region into a 7.2-Mb genomic region containing 51 newly predicted genes and candidate sex-determination genes AG2 and AG3.Many of these genes showed extremely low expression,likely attributed to hypermethylation in the gene body and promoter regions.Gene regulatory networks(GRNs)revealed that AG2 and AG3 are related to the regulation of stamen development in male flowers,while the AG1 gene is responsible for regulating female flowers'defense responses and secondary metabolite processes.Comparative analysis of GRNs showed that the NAC,WRKY,and MYB transcription factor families dominate the female GRN,whereas the MADS and MYB transcription factor families are prevalent in the male GRN.
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