Functional Analysis Of SNAREs Protein CcSec22 And CcSso1 In Cytospora Chrysosperma

Poplar canker caused by Cytospora chrysosperma is widely distributed in China and has serious damage.To understand the SNAREs（Soluble N-ethylmaleimide sensitive factor attachment receptors）protein in C.chrysosperma growth and pathogenic mechanism of the process.In this study,we analyzed the bioinformatics and transcriptional expression profile of SNAREs protein in the whole genome of C.chrysosperma,and studied the functions of two members:CcSec22（R-SNARE）and CcSso1（Q-SNARE）.The main results are as follows:（1）A total of 22 SNAREs protein members were identified in the genome of C.chrysosperma,which could be divided into Q-SNAREs and R-SNAREs according to the conserved sites in their protein sequences.Among them,17 Q-SNAREs proteins（6 Qa-SNAREs,4 Qb-SNAREs,6Qc-SNAREs and 1 Qbc-SNAREs）and 5 R-SNAREs proteins were identified.Compared with other plant pathogenic fungi,it was found that the SNARE proteins are well conserved in eukaryotes.（2）Expression profile analysis of SNAREs family genes showed that CcSec22,CcVam7,CcYkt6and other SNAREs genes were significantly differently expressed in the infection process of C.chrysosperma,suggesting that these SNAREs genes may play an important role in the infection process of C.chrysosperma.（3）The knockout vectors of CcSec22 and CcSso1genes were constructed by split marker method,and the knockout mutants of the two genes were successfully obtained by PEG mediated protoplast transformation.The results of phenotypic analysis showed that compared with wild-type strain,theΔCcSec22 andΔCcSso1 knockout mutants showed significant defects in growth and development.Cell wall integrity and CFW staining were observedΔCcSec22 knockout mutants were more tolerant to CFW and CR,with more hyphal septa and more chitin deposition in cell wall.However,theΔCcSso1knockout mutant had no significant change,but its tolerance to H₂O₂ was significantly enhanced.The results of inoculation test showed that knockout of CcSec22 or CcSso1 could significantly reduce the pathogenicity of the pathogen to poplar branches.In conclusion,the study systematically identified and expressed the SNAREs protein family of C.chrysosperma by bioinformatics and transcriptional analysis,and further studied the gene functions of CcSec22 and CcSso1,which provided important clues for the analysis of the pathogenic molecular mechanism of C.chrysosperma.