Differences in Anthocyanin Accumulation Patterns and Related Gene Expression in Two Varieties of Red Pear.

Jianlong Liu,Dingli Li,Ran Wang,Hongwei Sun,Zhiwei Deng,Shaoling Zhang,Jiankun Song

doi:10.3390/plants10040626

Abstract

Red pear is a popular fruit that is appreciated for its attractive and distinctive appearance and mild flavor. In this study, we investigated the mechanism underlying the red coloration of pear skin using the ‘Xinqihong’ cultivar—which was selected as a spontaneous bud sport mutant of the ‘Xinli 7′(Pyrus betulifolia Rehd.) variety and has a stronger red color that is retained in the mature fruit—as an experimental model. We compared the phenotype and gene expression patterns of the two varieties and found no significant differences at the early stage of fruit development. However, although the red color of ‘Xinli 7′ fruits began to fade 107 days after full bloom, that of ‘Xinqihong’ fruits persisted until the time of harvest. Transcriptome sequencing identified 639 genes that were differentially expressed between the two varieties, including genes related to light, calcium, and hormone signaling (e.g., PbPIF3, PbGA2ox, and the calmodulin related genes). Moreover, anthocyanin biosynthesis genes were downregulated as the red color of ‘Xinli 7′ fruits faded. These results provide insight into the molecular basis of color differences in red pears that can be useful for improving its fruit quality and commercial value.

Highlights

Fruit peel color is a key trait for judging fruit quality
We identified genes involved in anthocyanin biosynthesis among the DEGs (Figure 3b), 2.4.inFculnucdtiinognathl oAsneaelynsciosdoifnDg EflaGvsanone-3-hydroxylase (LOC103952304) and anthocyanidin reWduectiadseen(tLiOfieCd10g3e9n5e7s76i9n)v. oInlv‘eXdinilni 7a,ntthheofcoyramneinr wbiaosssyignnthifiecsaisntalymuopnrgegtuhleatDedEGats1(2F7igure 3b),DAFinBc.lMudeainngwhilteh, owseeanaelnyzceoddtihnegkeyflsatvruacntuornael-g3e-nheysdirnoaxnytlhaosceyan(inLOsyCn1th0e3s9is5b2y30q4R)T- and antPhCocRy. aEnxcidepint forrePdbuPcAtaLs, ethe(LexOpCre1s0si3o9n5l7e7v6e9ls).ofIPnbC‘HXiSn, lPibC7H′, I,thPbeDfFoRr,mPbeAr NwS,aPsbUsiFgGnTifiincantly upregulated at 127 days after full bloom (DAFB)
The red color of red pear is determined by the pattern of anthocyanin accumulation during fruit development

Summary

Introduction

Fruit peel color is a key trait for judging fruit quality. Anthocyanin is a water-soluble flavonoid and natural colorant that accumulates in many plant tissues, including fruit peel [1] and flower petals [2]. The anthocyanin contents of the ‘Hongyun’ pear and its mutant ‘Yunhongli 1 and ‘Meirensu’ are maximal in the mature fruit under the natural growing conditions in Yunnan, China [5]. The red sand pear variety ‘Mantianhong’ and its mutant ‘Aoguan’ show a fluctuating color, like European pears [6]. Anthocyanins, chlorophyll, and carotenoids are the main pigments responsible for the fruit color in pears [7]. The concentration and composition of anthocyanins determine the color of pear peel

Methods

Results

Discussion

Conclusion