Molecular Mechanism Of EIF2B? Regulating Turnip Mosaic Virus(TuMV)Disease Epidemic In Brassica Plants

Brassicaceae vegetables are important economic crops in China.With global climate change and intensive production,virus diseases have become the main diseases that affect the production of Chinese vegetables.Turnip mosaic virus(TuMV),one of the main virus diseases infecting cruciferous vegetables,can severely restrict the sustainable development of the cruciferous vegetable industry in China.From the previous findings in our lab,eIF2B? was mapped and cloned to be a recessive resistance gene against TuMV in Brassica juncea.Based on the identification of eIF2B?,in this study,we utilized a susceptible line STZ of Brassica juncea to investigate the role of eIF2B? gene in ABA response and its effect on the occurrence of viral diseases under different temperatures.Meantime,we generated some eIF2B? knock-out lines by CRISPR/Cas9 gene editing technology in K407,and investigated the molecular mechanism of eIF2B? gene regulating plant growth.The main results are as follows:1.Effects of the environmental condition on the occurrence of TuMV.Compared the plant susceptibility under different temperature treatments,we found that temperature can affect the occurrence of TuMV,which depend on the expression of eIF2B? gene.At 28 ?,the infected plants showed the typical symptoms of mosaic patterns on the leaves and plant stunting.And the transcript abundance of eIF2B? gene and the accumulation of TuMV reached the highest level.In addition,we found that exogenous ABA induced the expression of eIF2B? gene at a transcript level,indicating that exogenous ABA can regulate the occurrence of TuMV to some extent.2.Construction of eIF2B? gene knock-out mutants.The eIF2B? gene in Brassica napus was knocked out by CRISPR/Cas9 gene editing technology.According to the PCR identification and sequencing analysis,we constructed some eIF2B?(GSBRNA2T00057478001)knock-out mutant lines in Brassica napus.In addition,we found that the mutants grew faster than the wild type and could enter the stage of reproduction without vernalization under normal growth conditions,indicating that eIF2B? plays a role in regulating the flowering and growth process of the plants.3.The mechanism of eIF2B? gene regulating the growth and development in Brassica napus.Some differentially expressed genes during growth and development between wild type and mutants are identified by RNA-seq.These genes are mainly enriched in the process of photosynthesis and carbohydrate metabolism,as well as amino acid biosynthesis,which provides an vital basis for illustrating molecular mechanism by which eIF2B? regulates the growth and development of plant.