Genomic Analysis of the Glutathione S-Transferase Family in Pear (Pyrus communis) and Functional Identification of PcGST57 in Anthocyanin Accumulation

Abstract

Anthocyanin accumulation in vacuoles results in red coloration in pear peels. Glutathione S-transferase (GST) proteins have emerged as important regulators of anthocyanin accumulation. Here, a total of 57 PcGST genes were identified in the European pear ‘Bartlett’ (Pyrus communis) through comprehensive genomic analysis. Phylogenetic analysis showed that PcGST genes were divided into 10 subfamilies. The gene structure, chromosomal localization, collinearity relationship, cis-elements in the promoter region, and conserved motifs of PcGST genes were analyzed. Further research indicated that glutamic acid (Glu) can significantly improve anthocyanin accumulation in pear peels. RNA sequencing (RNA-seq) analysis showed that Glu induced the expression of most PcGST genes, among which PcGST57 was most significantly induced. Further phylogenetic analysis indicated that PcGST57 was closely related to GST genes identified in other species, which were involved in anthocyanin accumulation. Transcript analysis indicated that PcGST57 was expressed in various tissues, other than flesh, and associated with peel coloration at different developmental stages. Silencing of PcGST57 by virus-induced gene silencing (VIGS) inhibited the expression of PcGST57 and reduced the anthocyanin content in pear fruit. In contrast, overexpression of PcGST57 improved anthocyanin accumulation. Collectively, our results demonstrated that PcGST57 was involved in anthocyanin accumulation in pear and provided candidate genes for red pear breeding.

Genome-wide identification and expression analysis of glutathione S-transferase gene family to reveal their role in cold stress response in cucumber

“…Recently, plant GSTs associated with anthocyanin accumulation have received wide attention. IbGSTF4 in sweet potato ( Kou et al, 2019 ), MdGSTU12 in apple ( Zhao et al, 2021 ), PcGST57 in pear ( Li B.et al, 2022 ), PpGST1 in peach ( Zhao et al, 2020 ), and GhGSTF12 in cotton ( Shao et al, 2021 ) could modulate anthocyanin transport and accumulation. Furthermore, PbrGSTs are involved in the development of superficial scald by regulating redox balance in Chinese white pear ( Wang et al, 2018 ).…”

Transcriptome Analysis Reveals Roles of Sucrose in Anthocyanin Accumulation in ‘Kuerle Xiangli’ (Pyrus sinkiangensis Yü)

“…The fruits were treated with sterile distilled water or a solution of 3.0% sucrose (g/L) mixed with Tween-20 (0.01% v / v ) as a nonionic surfactant, and were then transferred to a light incubator for continuous light for three days. The conditions were as follows: 33,000 lux light intensity and 80% relative humidity at 17 °C, as described previously [ 14 ].…”

“…The total phenol and anthocyanin were extracted from pear peels treated with or without sucrose at indicated time points, and the measurements were performed as described previously with minor modifications [ 14 ]. About 0.2 g of peels were sampled and immediately frozen with liquid nitrogen and ground to powders in a 2 mL tube, and then the mixture was incubated in 1 mL solution of HCl/methanol (1/99, v / v ) in the dark for one hour at 4 °C.…”

“…Furthermore, the accumulation of anthocyanins is also associated with the transport of anthocyanins in plants. Three main pathways are reported to be involved in this transport process: the glutathione S -transferase (GST) family [ 14 ], the ATP-binding cassette (ABC) family, and the multidrug and toxic compound extrusion (MATE) family [ 15 , 16 ].…”

Genome-wide in silico identification of glutathione S-transferase (GST) gene family members in fig (Ficus carica L.) and expression characteristics during fruit color development

“…In Arabidopsis , a total of 53 GST family members have been identified ( Sappl et al, 2004 ). Seventy-nine members were found in rice ( Jain, Ghanashyam & Bhattacharjee, 2010 ), 59 in Gossypium raimondii , 49 in G. arboreum ( Dong et al, 2016 ), 90 in tomato ( Islam et al, 2017 ), 54 in peach ( Zhao et al, 2017 ), 69 in apple ( Jiang et al, 2019 ), 97 in kiwifruit ( Liu et al, 2019b ), 74 in tea ( Liu et al, 2019a ), 85 in pepper ( Islam et al, 2019 ), 179 in Brassica napus ( Wei et al, 2019b ), 130 in cultivated strawberry ( Fragaria × ananassa ) ( Lin et al, 2020 ), 49 in melon ( Wang et al, 2020 ), 92 in Medicago truncatula ( Hasan et al, 2021 ), 39 in Hami melon ( Song et al, 2021a ), and 57 in pear ( Li et al, 2022 ). Although the GST gene family has been extensively characterized in various plant species, its exploration has been limited in fig.…”