查看更多>>摘要：Seed hardness is an important quality trait of vegetable soybean.To determine the factors underlying seed hardness,two landraces with contrasting seed hardness,Niumaohuang(low seed hardness)and Pixiansilicao(high seed hardness),were selected from 216 soybean accessions originating from 26 provinces in China.The contents of the main components in vegetable soybean seeds such as water,soluble sugar,starch,protein and oil were measured,and transcriptome analyses performed during five stages of seed developmental.Transcriptome analysis indicates that during the middle and late stages of seed development,a large number of genes involved in the synthesis or degradation of starch,storage protein,and fatty acids were differentially expressed,leading to differences in the accumulation of stored substances during seed maturation among Niumaohuang and Pixiansilicao.The activity of cell proliferation and the formation of cell walls in the middle and late stages of seed development may also affect the hardness of seeds to a certain extent.In addition,weighted gene co-expression network analysis(WGCNA)was undertaken to identify co-expressed gene modules and hub genes that regulate seed hardness.Overexpression of a candidate seed hardness regulatory hub gene,GmSWEET2,resulted in increased seed hardness.In this study,the important role of GmSWEET2 in regulating the hardness of vegetable soybean seeds was verified and numerous potential key regulators controlling seed hardness and the proportion of seed components were identified,laying the groundwork for improving the texture of vegetable soybean.
查看更多>>摘要：Lignin accumulation can enhance the disease resistance of young tea shoots(Camellia sinensis).It also greatly reduces their tenderness,which indirectly affects the quality and yield of tea.Therefore,the regulation of lignin biosynthesis appears to be an effective way to balance tenderness and disease resistance in young tea shoots.In this study,we identified a laccase gene,CsLAC17,that is induced during tenderness reduction and gray blight infection in young tea shoots.Overexpression of CsLAC17 significantly increased the lignin content in transgenic Arabidopsis,enhancing their resistance to gray blight and decreasing stem tenderness.In addition,we found that CsLAC17 was negatively regulated by the upstream CsmiR397a by 5'-RLM-RACE,dual-luciferase assay,and transient expression in young tea shoots.Interestingly,the expression of CsmiR397a was inhibited during tenderness reduction and gray blight infection of young tea shoots.Overexpression of CsmiR397a reduced lignin accumulation,resulting in decreased resistance to gray blight and increased stem tenderness in transgenic Arabidopsis.Furthermore,the transient overexpression of CsmiR397a and CsLAC17 in tea leaves directly confirms the function of the CsmiR397a-CsLAC17 module in lignin biosynthesis and its effect on disease resistance.These results suggest that the CsmiR397a-CsLAC17 module is involved in balancing tenderness and gray blight resistance in young tea shoots by regulating lignin biosynthesis.
查看更多>>摘要：Fruit ripening is manipulated by the plant phytohormone ethylene in climacteric fruits.While the transcription factors(TFs)involved in ethylene biosynthesis and fruit ripening have been extensively studied in tomato,their identification in pear remains limited.In this study,we identified and characterized a HOMEODOMAIN TF,PbHB.G7.2,through transcriptome analysis.PbHB.G7.2 could directly bind to the promoter of the ethylene biosynthetic gene,1-aminocyclopropane-1-carboxylic acid synthase(PbACS1b),thereby enhancing its activity and resulting in increased ethylene production during pear fruit ripening.Yeast-two-hybrid screening revealed that PbHB.G7.2 interacted with PbHB.G1 and PbHB.G2.1.Notably,these interactions disrupted the transcriptional activation of PbHB.G7.2.Interestingly,PbHB.G1 and PbHB.G2.1 also bind to the PbACS1b promoter,albeit different regions from those bound by PbHB.G7.2.Moreover,the regions of PbHB.G1 and PbHB.G2.1 involved in their interaction with PbHB.G7.2 differ from the regions responsible for binding to the PbACS1b promoter.Nonetheless,these interactions also disrupt the transcriptional activation of PbHB.G1 and PbHB.G2.1.These findings offer a new mechanism of ethylene biosynthesis during climacteric fruit ripening.
查看更多>>摘要：Less-seed and seedless traits are desirable characteristics in watermelon(Citrullus lanatus).Hybridization between watermelon chromosomal translocated lines and wild lines significantly reduced seed counts in the hybrid fruits,approaching even seedless.However,the allelic relationships and the chromosomal translocation breakpoints from different sources are unclear,which limits their utility in breeding practices.This study focused on three groups of chromosomal translocation materials from different sources and conducted inheritance and allelic relationship analysis of translocation points.The results from third-generation genome sequencing and fluorescence in situ hybridization(FISH)revealed that the specific translocations in the naturally mutated material MT-a involved reciprocal translocations between Chr6 and Chr10.The Co60y radiation-induced mutant material MT-b involved reciprocal transloca-tions between Chr1 and Chr5,Chr4 and Chr8.The Co60y radiation-induced mutant material MT-c involved complex translocations among Chr1,Chr5,and Chr11.Cytological observation showed that heterozygous translocation hybrids showed chromosomal synapsis abnormalities during meiotic diakinesis.Further,dominant and codominant molecular markers were developed on both sides of the translocation breakpoints,which could facilitate rapid and efficient identification of chromosome translocation lines.This study provides technical guidance for utilizing chromosomal translocation materials in the development of less-seed watermelon varieties.
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