摘要
Petal blotch is a prevalent pigmentation pattern observed in the Xibei tree peony(Paeonia rockii), possessing significant aesthetic value and playing a crucial role in the species' reproduction and fitness. Despite years of research, deciphering the molecular mechanisms underlying blotch formation remains challenging. As is well known, floral pigmentation is frequently associated with the familiar R2R3-MYB transcription factors. The key MYB anthocyanin activators of P. rockii ‘Shu Sheng Peng Mo' were previously reported in our preceding study. In this study, we identified and characterized three R2R3-MYBs, Pr MYBi1, Pr MYBi2, and Pr MYBi3, which belong to subgroup 4(SG4) and play repressor roles in anthocyanin biosynthesis. A quantitative real-time PCR(q RT-PCR) assay indicated that the expression of Pr MYBi1 and Pr MYBi3 gradually increased during flowering development and was substantially up-regulated in non-blotch compared to blotch. Yeast one-hybrid and dualluciferase assays demonstrated that Pr MYBi(1-3) directly target the anthocyanin structural genes and repress their transcription. The genetic transformation of tobacco demonstrated that the overexpression of Pr MYBi(1-3) decreased anthocyanin accumulation in flowers, with Pr MYBi1 serving as the most effective repressor. Our results revealed that SG4 R2R3-MYBs negatively regulate the anthocyanin pathway in P.rockii conservatively, and we provide the definite members. These findings will advance future research to unravel the mystery of blotch pattern formation.
基金
supported by the National Natural Science Foundation of China(Grant No.32030095)
the Key project at central government level:The ability establishment of sustainable use for valuable Chinese medicine resources(Grant No.2060302).
