RcMPK3 positively regulates Rosa chinensis ‘Old Blush’ in response to Botrytis cinerea

Gray mold is the most serious fungal disease in rose after harvest and during transportation. The MPK3 gene participates in the plant response to stress. Here, RT-PCR technology was used to isolate and clone the full length of the RcMPK3 gene based on whole-genome data of Rosa chinensis ‘Old Blush’ Jacq. Results showed that the open reading frame (ORF) sequence of RcMPK3 was 1113 bp long and encoded 370 amino acids. Phylogenetic analysis showed that the RcMPK3 protein was clustered with FvMPK3. The full-length sequence of the RcMPK3 gene was analyzed, which showed that RcMPK3 was composed of six exons and five introns. There were 10 cis-elements in RcMPK3. Quantitative real time PCR (qPCR) analysis showed that RcMPK3 was induced by salicylic acid (SA) and jasmonic acid (JA). RcMPK3 expression significantly increased under Botrytis cinerea stress. Functional analysis of RcMPK3 by VIGS showed that lesion diameter in the gene-silenced plant was significantly larger than that in the control, indicating that the RcMPK3 gene positively regulates the resistance of rose to B. cinerea.