| Wheat gibberellic disease(Fusarium head blight,FHB)is an important diseases on cereal crops,and were spread in all of the world’s wheat production areas,especially severely harmed the mild and humid regions.FHB has been most distributed in southwest and northeast wheat diseases in China.In our country,there are mainly Fusarium graminearuma and Fusarium asiaticum,which is mainly distributed in south of the Yangtze river that the annual average temperature is greater than 15 degrees.The other is primarily distributed in north of the Yangtze river,whose annual average temperature is less than 15 degrees,such as Hebei、Shandong province etc.With the year after year outbreak of FHB and increase of resistance to drugs,the duty to control FHB is urgent.Based on the whole genome sequencing results of F.asiaticum standard strain 2021,and then we compared the whole genome of F.asiaticum and F.graminearum and found some genes that only exist in F.asiaticum or its homology in F.graminearum genome is very low.Based on the study of funtions of this genes so that we are able to better understand growth and development process in F.asiaticum and the distributional theory of two strains.By means of bioinformatics analysis of the structural and composition differences between these two strain’s genome,we explored one dihydrodipicolinate synthase(DHDPS)gene in F.asiaticum,named FaDHDPS1 and two pisatin demethylase(Pda)genes,respectively named FaPDA1 and FaPDA2.Dihydrodipicolinate synthase(DHDPS)is an allosteric enzyme,which catalyzes the first step in the lysinebiosynthesis pathway of bacteria and plants.However,to date the functions of DHDPS enzymes have not been characterized in any phytopathogenic,including Fusarium spp.In this study,we were initiated to investigate the role of DHDPS in F.asiaticum by using target gene deletion strategy and then we found that FaDHDPS1 disruption mutant was defective in conidiation、penetration、virulence and an increased sensitivity to low temperature and to substance that undermined the cell wall,and that FaDHDPSl disruption mutant was defective in hyphal branching and an increased sensitivity to sodium pyruvate、carbon and nitrogen sources.The location of FaDHDPS1 is mainly localized to the lipid droplet in conidia.As the conidium germination and the degradation of lipid drops,GFP signals dispersion in the cytoplasm.Pisatin demethylase(Pda)was shown to be the first member of a new family of cytochrome P450s,CYP57A that has the function of degrading pisatin produced by garden pea as phytoalexin.When knocked out FaPDAl and FaPDA2,both mutants weaken the pathogenicity on flowering wheat heads and wheat coleoptiles and shown defective in penetration.The level of producing toxin was lower in mutants and expression of the toxin-related gene Tri5 and Tri6 were significantly down-regulated in the mutants.Taken together,the laboratory findings confirmed that FaDHDPS1、FaPDA1 and FaPDA2 are required for several F.asiaticum developmental processes and activities,which help us better understand the growth and development process and distribution of F.asiaticum. |
