Bioinformatics Analysis of the Tomato SlPR5 Gene Family and the Thaumatin-like Protein SlPR5-3 Positively Regulates Tomato Resistance to Pst DC3000

Studies on how <i>SlPR5</i> genes are involved in <i>Pst</i> DC3000 disease resistance response are lacking. Here, 27 members of the tomato <i>SlPR5</i> gene family were identified and analyzed. Analysis of conserved structural domains and promoter structure revealed that <i>SlPR5</i> family members are structurally conserved and contain a variety of antidisease and antistress response elements. We screened out <i>SlPR5-3</i>, which was significantly upregulated, through an analysis of the expression pattern of <i>Pst</i> DC3000 in tomato after inoculation. We generated <i>SlPR5-3</i> mutants via CRISPR/Cas9 gene editing and <i>SlPR5-3-</i>overexpressing tomato plants to elucidate the function of this gene. The results showed that the <i>SlPR5-3</i> overexpression lines had reduced lesions, significantly lower pathogen counts, and significantly higher activity indexes of defense-related enzymes, while the mutant lines showed the opposite, indicating that the <i>SlPR5-3</i> gene positively regulates the immune response against <i>Pst</i> DC3000 in tomato. In this study, we systematically mined and analyzed the tomato <i>SlPR5</i> family genes, screened out the important genes in this family for the regulation of <i>Pst</i> DC3000 disease resistance, and verified the disease resistance regulatory function of <i>SlPR5-3</i>, laying the foundation for the theoretical study of tomato <i>Pst</i> DC3000 disease resistance and providing a new molecular target for the future breeding of tomato disease resistance.