Differences among the Anthocyanin Accumulation Patterns and Related Gene Expression Levels in Red Pears

Abstract

Differences in coloration exist among red pear cultivars. Here, we selected six red pear cultivars with different genetic backgrounds to elucidate the characteristics of fruit pigmentation. We detected anthocyanin contents and the expression levels of anthocyanin synthesis-related genes in these cultivars at different stages of fruit development. The anthocyanin contents of all six cultivars showed a rise–drop tendency. Principal component and hierarchical cluster analyses were used to distinguish the types of cultivars and the genes crucial to each anthocyanin accumulation pattern. The six cultivars were divided into three groups. Red Zaosu were clustered into one group, Red Sichou and Starkrimson into another group, and Palacer, Red Bartlett, and 5 Hao clustered into a third group. The expression levels of F3H, UFGT2, MYB10, and bHLH3 were similar among the differential coloration patterns of the six cultivars, suggesting a critical and coordinated mechanism for anthocyanin synthesis. Anthocyanin transporters (GST) and light-responsive genes, such as COP1, PIF3.1, and PIF3.2 played limited roles in the regulation of anthocyanin accumulation. This study provides novel insights into the regulation of anthocyanins synthesis and accumulation in red pears.

PbMYB120 Negatively Regulates Anthocyanin Accumulation in Pear

“…Anthocyanin accumulation is regulated by both positive and negative regulators [43]. The expression patterns of anthocyanin activators PbMYB10 and PbMYB10b are consistent with the accumulations of anthocyanin in many pear cultivars [21,44]. In this study, the expression pattern of PbMYB120 was also consistent with the accumulation of anthocyanin in many pear cultivars (Figures 2 and 4).…”

Dynamic Changes of the Anthocyanin Biosynthesis Mechanism During the Development of Heading Chinese Cabbage (Brassica rapa L.) and Arabidopsis Under the Control of BrMYB2

“…In this respect, MdMYBA, MdMYB1, MdMYB9, MdMYB10, MdMYB110a, and MdMYB11 are all identified R2R3-MYBs that regulate anthocyanin biosynthesis in the peel and flesh of apples: MdMYB1, MdMYB10, and MdMYBA have higher homologies and similar functions for activating LBGs; MdMYB110a is mainly responsible for anthocyanin accumulation of red fleshes in fruits; MdMYB9 and MdMYB11 have a relatively distant relationship to the aforesaid MdMYBs, and the module mechanism of them is to respond to jasmonic acid induction and then activate EBGs such as MdCHS , MdCHI , and MdF3H , as well as several LBGs such as MdANS , MdDFR , and MdANR ; both MdMYBL2 and MdMYB6 could inhibit anthocyanin biosynthesis via different mechanisms, whereby the former functions as a repressor interacting with MdbHLH3 to indirectly inhibit the upregulation of MdMYB10 , MdbHLH3 , MdDFR , and MdUFGT , while MdMYB6 could inhibit anthocyanin biosynthesis by regulating MdANS and MdGSTF12 during the coloration of developing fruits ( Naing and Kim, 2018 ; Wang et al, 2019 ; Xu H. et al, 2020 ). The expression levels of F3H , UFGT2 , MYB10 , and bHLH3 might be critical and coordinated for the anthocyanin synthesis in pear fruits’ development, whereas GST and key light-responsive genes, such as COP1 , PIF3.1 , and PIF3.2 , played limited roles in its regulation ( Wu et al, 2019 ). In vegetable crops, studies pay particular attention to either vegetative developing or the fruit development.…”

MYB-Mediated Regulation of Anthocyanin Biosynthesis

“…When Arabidopsis was exposed to far-red light, phyA could promote anthocyanin accumulation by enhancing AtMYB75 abundance and AtDFR , AtLDOX and AtUFGT expression [ 82 ]. To maintain the balance of anthocyanins, light signaling pathways downstream of constitutively photomorphogenic 1 (COP1: ubiquitin E3 ligase morphogenesis protein) TF suppress the accumulation of anthocyanins [ 161 ]. COP1 is found in the nucleus under dark conditions, where it targets photomorphogenetic activating TFs and mediates their degradation [ 162 ].…”