Abstract:

In order to further understand the molecular mechanism of GLV peptide in peach fruit ripening and softening，the PpRGI gene family was identified in peach genome, and its expression levels during fruit development in melting flesh and stony hard peach were detected by qRT-PCR. Additionally，we also used qRT-PCR to detect the expression level of PpRGI gene family in stony-hard peach fruit under NAA treatment，and in peach callus under exogenous peptide treatment. The results showed that 6 PpRGI candidate genes were found in the peach genome. The PpRGI contained the LRR conserved domain and signal peptide at the N-terminus. The phylogenetic analysis revealed that PpRGI gene family was divided into 2 groups. Expression analysis showed that PpRGI1，PpRGI3 and PpRGI4 were expressed in different tissues of melting-flesh peach and their expression levels in melting-flesh peach fruits were higher than in stony-hard peach fruits. PpRGI1 has the highest expression in different peach types and the expression of PpRGI1 was increased under NAA and peptide treatment. These results suggested that the PpRGI gene family members are highly and structurally conserved and PpRGI1 may be involved in the biosignaling pathway of peach peptide hormones.

Key words: Prunus persica, GLV peptide, PpRGI, receptor