Prediction and Functional Analysis on Secretory Proteome from the Whole Genome of Botryosphaeria dothidea

The full genome of Botryosphaeria dothidea strain BDLA16-7, a pathogenic fungus from an infected Carya cathayensis tree, comprising 13 130 protein sequences, which were analyzed to predict and functionally characterize secretory proteins by various prediction and analysis tools. The results indicated that in the encoded protein sequences of the BDLA16-7 whole genome, there were 898 sequences typical characteristics of secretory proteins, accounting for 6.84% of the total ones. The amino acid composition of the secretory protein group showed the following characteristics: the content of non-polar and hydrophobic amino acids was significantly higher than that of polar and hydrophilic amino acids, accounting for 43.6 % and 27.7 %, respectively. The length of the protein is mainly distributed between 100 and 600 amino acids. Alanine ( A ) is the most common non-polar amino acid, while aspartic acid ( D ) and glutamic acid ( E ) with charged side chains appear less frequently. The amino acids at the cleavage sites-3 and-1 of the signal peptide are relatively conserved, and the typical amino acid combination is A-S-A, which conforms to the characteristics of A-X-A type.Within the secretory protein group, 600 sequences could be fully annotated for their functions, among them, 229 involved in the transport and metabolism of carbohydrates. Among the BDLA16-7 secretory proteins, there were a total of 271 potential effector proteins, with 14 of them showing high similarity to effectors associated with other pathogenic organisms. BDLA16-7 secretory protein group contains 293 CAZymes, dominated by GHs family members. Analysis were made on the length distribution characteristics, functional classification, amino acid composition of signal peptide cleavage site, type of cleavage site and number of CAZymes of secretory proteome of B. dothidea, as well as on the subfamily composition of cellulase, pectinase and xylanase in CAZymes. 14 potential effectors closely related to pathogenicity were screened.