| Wheat crown rot is one of the devastating soil borne diseases,which have occurred significantly in Henan,Shandong,Anhui,Shaanxi,and other provinces in China in recent years.The main pathogen causing wheat crown rot is Fusarium pseudograminearum,whose hyphae and spores help the pathogen to overwinter and is also the primary infection source of the wheat crown rot.The ascospore shell of F.pseudograminearum can be observed during the filling stage of wheat.F.pseudograminearum can also cause wheat scab and infect crops such as corn,barley,and alfalfa.The damage of wheat crown rot caused by F.pseudograminearum is very serious.Therefore,searching for important functional proteins in the interaction between F.pseudograminearum and wheat and exploring their functions have important theoretical significance for preventing and controlling wheat crown rot.Effectors are small molecular proteins secreted by pathogen during the infection with hosts,and have been shown to play an important role in the pathogenesis of pathogen.However,in recent years,there have been relatively few studies on the effectors of F.pseudograminearum.Base on the genome sequencing research of F.pseudograminearum,we preliminarily screened an effector Fp00392 that can trigger the plant cell death by transient expression in tobacco.In this study,we focus on the study about the pathogenesis of effector Fp00392 during the infection of F.pseudograminearum in wheat.The obtained research results are as follows:1.Sequence analysis revealed that the encoded protein Fp00392 did not contain a conserved domain or transmembrane structure,but included an N-terminal signal peptide structure.Phylogenetic tree analysis revealed that the Fp00392 gene is highly homologous to the reported Vm E02,Fg02685 genes;2.The signal peptide structure of the secreted protein Fp00392 is verified that it can secrete the mature protein Fp00392 outside the cell through including yeast secretion system,transient expression on tobacco,and inoculating overexpression transformant on wheat;3.Fp00392 gene knock-out experiment mediated by PEG found that knockout of Fp00392 gene did not affect the mycelial growth rate of F.pseudograminearum,and had no effect on the response of F.pseudograminearum to salt stress.However,knockout of Fp00392 gene caused the hyphal density of F.pseudograminearum to become loose,and affected the synthesis of cell wall of F.pseudograminearum.Knocking out the Fp00392 gene reduced the sensitivity of F.pseudograminearum to oxidative stress;4.Fp00392 knock-out mutant,complementation mutant and wild-type inoculation showed that the disease symptoms at the coleoptile inoculated with knock-out mutant are significantly reduced,and the disease spot expansion is slower than that of wild-type and complementation mutant.These results indicate that the Fp00392 plays an important role in the pathogenesis of F.pseudograminearum.5.Transcriptome analysis revealed that compared to wild-type F.pseudograminearum,Fp00392 knock-out mutant infection resulted in significant differences in the transcription of 3296 genes from wheat.Among 3296 genes,554 genes are significantly up-regulated,which suggest that Fp00392 may suppress the transcription of these 554 genes during the process of F.pseudograminearum infection.Then,KEGG analysis found that the 554 genes involved in plant metabolism,genetic information,signal transduction,and other pathway.In summary,the signal peptide structure of the secreted protein Fp00392 has a secretory function,and Fp00392 is involved in the synthesis of cell membrane and cell wall and the response to oxidative stress of F.pseudograminearum.Fp00392 plays a significant role in the pathogenicity of F.pseudograminearum,and may be involved in the regulation of plant metabolism and genetic information processing.This finding provides a theoretical basis for further research on the pathogenesis of F.pseudograminearum,and provides genetic resources for further control of F.pseudograminearum and cultivation of disease-resistant varieties. |
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