Regulatory Mechanisms On Enhanced Fruit Coloring By White Non-woven Bags As Compared With Yellow Paper Bags

Anthocyanin is main pigment in ripe peach. It has been reported that anthocyanin biosynthesis regulated by the transcription factor (TF) complex MYB-bHLH-WD40(MBW). In present study, we confirmed the role of PpWD40-1in regulating anthocyanin biosynthesis. On this basis, we also investigated the effects of fruit bags with different light transmission properties on anthocyanin accumulation and expression of related structural and regulatory genes in peach, and thus to gain a comprehensive understanding of the effects of light on anthocyanin accumulation. The results are shown as follows:1. We validate the functional WD40member regulating anthocyanin biosynthesis in peach. Forty four WD40members were identified in the peach genome and it was found that ppa008187m, designated as PpWD40-1, shared highest homology with known plant WD40members regulating anthocyanin biosynthesis. Tobacco transient expression patch assay was carried out with either binary, containing MrMYB1and MrbHLHl, or ternary, containing MrMYB1, MrbHLHl, and PpWD40-1, combinations for the induction of anthocyanins. It showed that PpWD40-1enhanced the expression of MrMYB1and MrbHLHl, consequently regulate the anthocyanin production.2. The mechanism at aspect of expression of structural genes and regulatory genes that WH-N bagging resulted in increased peel redness in peach was revealed. Anthocyanin accumulation in peel significantly increased through WH-N bagging as compared with YE-P, and this was due to enhanced expression of several structural genes, such as CHS, DFR and UFGT, as well as all regulatory genes investigated, three MYBs (MYB10.1, MYB10.2, MYB10.3), bHLH3, and WD40-1.