Molecular cloning and expression analysis of PpPHOT1 and PpCRY2 in postharvest peach fruits

Blue light is one of the most important environmental factors to regulate plant growth and development. In order to investigate the effect of blue light on carotenoid synthesis of peach fruit, the full-length c DNAs of two blue light photoreceptor genes (phototropin and cryptochrome) were isolated from peach fruit by RT-PCR and RACE. Sequencing and bioinformatics analyses indicated that PpPHOT1 protein contain two LOV domains in the N-and a serine/threonine protein kinase domain, in the C-termini, which are conserved domains of phototropin, respectively. PpCRY2 protein contained a typical N-terminal photolyase homologous region (PHR) and a C-terminal DAS motif. The blue light treatment increased the expression of PpPHOT1 and PpCRY2 in both Jinli and hujingmilu fruit. In addition, a significantly higher level of PpPHOT1 and PpCRY2 transcripts in blue light-treated fruit was found in Jinli as compared to that in hujingmilu fruit. These results suggest that PpPHOT1 and PpCRY2 are the important response factors in sensing blue light in peach fruit, especially in Jinli fruit. The results of this study provided some valuable information for further disclosing the regulatory mechanism of blue light on carotenoid synthesis of peach fruit. (authors)