The Function and Mechanism of Pathogenesis-Related 5 Protein Resistance in Cherry Tomato in Response to Alternaria alternata

Pathogenesis-related protein 5 (PR5) is encoded by the host and is related to host resistance to biological and abiotic factors. In the present study, we constructed interference expression vector pBIA-LePR5-RNAi and analyzed the resistance of transgenic tomatoes to Alternaria alternata (A. alternata). To understand the regulatory mechanism of LePR5 gene, green fluorescent protein fluorescence cellular localization and promoter functional elements were investigated. Results showed that the expression of resistance gene declined, and the morbidity of transgenic tomatoes was significantly higher than the untransformed plants. Fluorescence observation of onion epidermal cell indicated that LePR5 protein was mainly distributed in the cell membrane, apoplast, and nucleus. Furthermore, sequence analysis indicated the presence of several eukaryotic transcription factor-binding motifs, which contained TATA-box and CAAT-box; plant hormone response element, such as ABRE, TCA-element, and TGA-element; Box-W1, WUN-motif inducible transcribed by fungal elicitor and wound; and so on.