| Innate immunity is employed by plants against pathogenic microorganisms for the survival.When plants are challenged with pathogenic microorganisms,various responses are activated including the activation of programmed cell death.Root is a crucial organ for plants and its system architecture mainly depends on the development of lateral root.The developed lateral roots will benefit the uptake of water and nutrients,thereby enhancing crop yields.Therefore,it is of great significance to understanding the linking innate immunity and lateral root development.The results of this study are as follows:1.In this study,we use a bis1 mutant,which is defective in development and innate immunity.Phenotypic analysis showed that bis1 mutant appeared slow growth,late flowering,and premature senescence.By trypan blue staining,bis1 mutant showed cell death in the leaves,and the first true leaves started to appear cell death at 16 days.This may be induced by the accumulated salicylic acid.The content of salicylic acid in bis1 mutant was significantly increased,about 1.6 times higher than that of Col-0.Genetic analysis showed that cell death of the bis1 mutant can be suppressed by the salicylic acid mutant npr1-1,sid2-1 and pad4-1.These further support that cell death in the bis1 mutant is correlated with the increased salicylic acid.In order to confirm the function of BIS1 gene,a complementary material was generated and designated as pBIS1::gBIS1-GFP plants.Analysis showed all the defects in bis1 mutant were completely restored.We concluded that BIS1 gene is involved in regulating salicylic acid-mediated cell death.Previous studies have shown that nucleopore is involved in regulating salicylic acid-mediated cell death.To address whether it is the case in bis1 mutants,several mutated sites in the genes encoding nucleopore protein were introduced into bis1 mutants,such as NUP107,NUP155,NUP133,NUP96,NUP58 and SEC13.These double mutants were also analyzed.Analysis showed that cell death in bis1 mutant weren’t supressed by nup107,nup155,nup133,nuo96,nup58 and sec13.2.bis1 mutant also have observed defects in root development and seeds.Compared with the wild type,the root hair in bis1 was denser and longer than those in the wild type.Lateral root number significantly reduced.Next,we observed differences in the development of the lateral root primordia between wild type and bis1 mutants.Analysis showed lateral root primordia development in bis1 mutant most stayed in stage Ⅳ-Ⅶ,and couldn’t turn into lateral root.Then,we observed root development and seeds in pBIS1::gBIS1-GFP plants,analysis showed the defects in root development and seeds in bis1 mutant were completely restored.We observed the lateral root development in sid2-1 bis1,ein2-1 pad4-1 bis1 and npr1-1 bis1,these had the same phenotype with bis1 mutant.We concluded that BIS1 gene is involved in regulating root development and seeds.3.In order to explore the molecular mechanism of BIS1 protein involved in innate immunity and development,we analyzed the transcriptional profiling of wild type and bis1.A dramatic difference between two plants indicating that BIS1 might regulate alternative splicing,especially intron retained splicing.In addition,the enrichment of differential genes in bis1 were observed to participate in the immune defense process by influencing the expression of stress resistance and disease resistance genes and regulating multiple metabolism and secondary metabolism processes. |
