Changes of chlorogenic acid content and its synthesis-associated genes expression in Xuehua pear fruit during development

According to synthetic pathway of plant chlorogenic acid (CGA), the expression patterns of genes encoding enzymes that are associated with CGA synthesis were studied in normally developed Xuehua pear fruit. The study demonstrated that CGA content in peel and flesh of Xuehua pear decreased as fruit development progressed, with a higher level in peel. The expression levels of PbPAL1, PbPAL2, PbC3H, PbC4H, Pb4CL1, Pb4CL2, Pb4CL6, PbHCT1 and PbHCT3 genes decreased in fruit, which was consistent with the pattern of variation in CGA content. That indicated that these genes might be key genes for influencing fruit CGA synthesis in Xuehua pear. However, Pb4CL7 gene expression profile is not consistent with variation of CGA content, hence, it may not be a key gene involved in CGA synthesis.