Dynamic Changes in Anthocyanin Accumulation and Cellular Antioxidant Activities in Two Varieties of Grape Berries during Fruit Maturation under Different Climates

Abstract

As popularly consumed fruit berries, grapes are widely planted and processed into products, such as raisins and wine. In order to identify the influences of different climatic conditions on grape coloring and quality formation, we selected two common varieties of grape berries, 'Red Globe' and 'Xin Yu', for investigation. Grapes were separately grown in different climates, such as a temperate continental arid climate and a temperate continental desert climate, in Urumqi and Turpan, China, for five developmental stages. As measured, the average daily temperature and light intensity were lower in Urumqi. Urumqi grape berries had a lower brightness value (L*) and a higher red-green value (a*) when compared to Turpan's. A RT-qPCR analysis revealed higher transcriptions of key genes related to anthocyanin biosynthesis in Urumqi grape berries, which was consistent with the more abundant phenolic substances, especially anthocyanins. The maximum antioxidant activity in vitro and cellular antioxidant activity of grape berries were also observed in Urumqi grape berries. These findings enclosed the influence of climate on anthocyanin accumulation and the antioxidant capacity of grapes, which might enlarge our knowledge on the quality formation of grape berries and might also be helpful for cultivating grapes with higher nutritional value.

Keywords: anthocyanins; antioxidant capacity; different climates; grape berry development.

Figure 1

Gene relative expression levels of the anthocyanin biosynthesis pathway in grape berries during the five developmental stages in Urumqi and Turpan. The data presented are as mean ± SD of triplicates. PAL encodes phenylalanine ammonia lyase; 4CL encodes 4-coumarate-CoA ligase; CHS2 encodes chalcone synthase; CHI encodes chalcone isomerase; F3H encodes flavanone 3-hydroxylase; F3′H encodes flavonoid-3′-hydroxylase; F3′5′H encodes flavonoid-3′5′-hydroxylase; DFR encodes dihydroflavonol-4-reductas; ANS encodes anthocyanin synthase; and ANR encodes anthocyanidin reductase. RG stand for ‘Red Globe’ grapes; XY stand for ‘Xin Yu’ grapes; U stands for Urumqi; T stands for Turpan. Bars with different letters differ significantly at p < 0.05.

Figure 2

Antioxidant activities of grape berries in ORAC values and CAA values during the five developmental stages in Urumqi and Turpan. (A) ORAC values; (B) CAA values under no PBS wash protocol; (C) CAA values under the PBS wash protocol; (D) cell uptake rate. Bars with different letters differ significantly at p < 0.05. RG−U, Urumqi ‘Red Globe’ grapes; RG−T, Turpan ‘Red Globe’ grapes; XY−U, Urumqi ‘Xin Yin’ grapes; XY−T, Turpan ‘Xin Yu’ grapes.

Figure 3

Pearson’s correlation analysis in grape berries during the five developmental stages in Urumqi and Turpan. (A) Gene expression and composition; (B) composition and color difference values; (C) composition and antioxidant quality; (D) composition. C, FA, EC, PB1, PB2, Dp, Cy, Pt, Pn, Mv, and AC stand for catechin, ferulic acid, epicatechin, procyanidin B1, procyanidin B2, delphinidin-3-O-glucoside, cyanidin-3-O-glucoside, petunidin-3-O-glucoside, peonidin-3-O-glucoside, mal-vidin-3-O-glucoside, and total anthocyanins, respectively. *, Significant at 5% probability levels; **, significant at 1% probability levels.

Figure 4

Principal component analysis (A) and cluster analysis (B) in grape berries during the five developmental stages in Urumqi and Turpan. RG−U, Urumqi ‘Red Globe’ grapes; RG−T, Turpan ‘Red Globe’ grapes; XY−U, Urumqi ‘Xin Yin’ grapes; XY−T, Turpan ‘Xin Yu’ grapes. RG−US1, RG−US2, RG−US3, RG−US4, RG−US5, XY−US1, XY−US2, XY−US3, XY−US4, RG−US5, RG−TS1, RG−TS2, RG−TS3, RG−TS4, RG−TS5, XY−TS1, XY−TS2, XY−TS3, XY−TS4, and RG−TS5 stand for grape berry samples. C, FA, EC, PB1, PB2, Dp, Cy, Pt, Pn, and Mv stand for catechin, ferulic acid, epicatechin, procyanidin B1, procyanidin B2, delphinidin-3-O-glucoside, cyanidin-3-O-glucoside, petunidin-3-O-glucoside, peonidin-3-O-glucoside, and malvidin-3-O-glucoside, respectively.