Identification of the TLP gene family in Rosaceae and function of PbrTLP28 in leaf disease resistance

Thaumatin-like proteins (TLPs) are induced by various biotic and abiotic signals, exhibit antifungal activity, and serve essential functions in plant development and stress defense. However, studies on the identification of TLPs in Rosaceae fruit trees and their specific functions in leaf disease resistance remain limited. In this study, 177 TLPs were characterized from five Rosaceae genomes ( Fragaria vesca , Malus domestica , Pyrus bretschneideri , Prunus mume , and Prunus persica ) and classified into 11 subfamilies (Groups 1-11) according to their phylogenetic and structural features. Diverse gene duplication modes facilitated the expansion of the TLP family, whereas purifying selection served as the primary driving force of TLP evolution. Notably, expression analysis revealed that PbrTLP28 was significantly upregulated following black spot disease infection. Signal peptide prediction, conserved domain analysis, and subcellular localization assays confirmed that PbrTLP28 is a secreted protein. Functional assays demonstrated that silencing PbrTLP28 attenuated the resistance of pear leaves to black spot disease, indicating that PbrTLP28 functions in disease resistance. Collectively, these findings provide significant insights into TLP gene function, expression, and evolution in Rosaceae.