Nutritional Component Analyses in Different Varieties of Actinidia eriantha Kiwifruit by Transcriptomic and Metabolomic Approaches

Abstract

Actinidia eriantha is a unique germplasm resource for kiwifruit breeding. Genetic diversity and nutrient content need to be evaluated prior to breeding. In this study, we looked at the metabolites of three elite A. eriantha varieties (MM-11, MM-13 and MM-16) selected from natural individuals by using a UPLC-MS/MS-based metabolomics approach and transcriptome, with a total of 417 metabolites identified. The biosynthesis and metabolism of phenolic acid, flavonoids, sugars, organic acid and AsA in A. eriantha fruit were further analyzed. The phenolic compounds accounted for 32.37% of the total metabolites, including 48 phenolic acids, 60 flavonoids, 7 tannins and 20 lignans and coumarins. Correlation analysis of metabolites and transcripts showed PAL (DTZ79_15g06470), 4CL (DTZ79_26g05660 and DTZ79_29g0271), CAD (DTZ79_06g11810), COMT (DTZ79_14g02670) and FLS (DTZ79_23g14660) correlated with polyphenols. There are twenty-three metabolites belonging to sugars, the majority being sucrose, glucose arabinose and melibiose. The starch biosynthesis-related genes (AeglgC, AeglgA and AeGEB1) were expressed at lower levels compared with metabolism-related genes (AeamyA and AeamyB) in three mature fruits of three varieties, indicating that starch was converted to soluble sugar during fruit maturation, and the expression level of SUS (DTZ79_23g00730) and TPS (DTZ79_18g05470) was correlated with trehalose 6-phosphate. The main organic acids in A. eriantha fruit are citric acid, quinic acid, succinic acid and D-xylonic acid. Correlation analysis of metabolites and transcripts showed ACO (DTZ79_17g07470) was highly correlated with citric acid, CS (DTZ79_17g00890) with oxaloacetic acid, and MDH1 (DTZ79_23g14440) with malic acid. Based on the gene expression, the metabolism of AsA acid was primarily through the L-galactose pathway, and the expression level of GMP (DTZ79_24g08440) and MDHAR (DTZ79_27g01630) highly correlated with L-Ascorbic acid. Our study provides additional evidence for the correlation between the genes and metabolites involved in phenolic acid, flavonoids, sugars, organic acid and AsA synthesis and will help to accelerate the kiwifruit molecular breeding approaches.

Analysis of organic acid metabolism reveals citric acid and malic acid play major roles in determining acid quality during the development of kiwifruit (Actinidia eriantha)

“…49,50 Similarly, a recent study on three A. eriantha genotypes indicated that the expression of a kiwifruit gene, MDH1, exhibited a significant positive correlation with the content of malic acid. 43 However, although the expression level of AePEPC2 was positively correlated with PEPC activity during fruit development, the correlation value was not significant (Fig. 6).…”

“…In fruit of another kiwifruit cultivar, A. eriantha ‘Ganmi 6’, the predominant organic acid are quinic acid and citric acid, accounting for 62.68–83.21% of the total organic acids during different developmental periods 26 . For other three varieties of A. eriantha , the main organic acids in fruit are citric acid, succinic acid and d ‐xylonic acid 43 . Therefore, for kiwifruit, the accumulation patterns, types, and contents of organic acids in fruit probably exhibit obviously different features, mainly depending on the species or varieties.…”

“…26 For other three varieties of A. eriantha, the main organic acids in fruit are citric acid, succinic acid and D-xylonic acid. 43 Therefore, for kiwifruit, the accumulation patterns, types, and contents of organic acids in fruit probably exhibit obviously different features, mainly depending on the species or varieties.…”

Agrobacterium rhizogenes-mediated marker-free transformation and gene editing system revealed that AeCBL3 mediates the formation of calcium oxalate crystal in kiwifruit

“…deliciosa, A. eriantha, and A. arguta) have been developed as commercial cultivars so far. Due to its nutrient and commercial values, extensive investigations on genomics (Huang et al 2013;Pilkington et al 2018;Tang et al 2019;Wu et al 2019;Yue et al 2023), transcriptomics (Choi et al 2022;Tahir et al 2022;Miao et al 2023;Xiong et al 2023), and metabolomics (Abid et al 2022;Jia et al 2022;Wang et al 2022a;Wang et al 2022c;Shu et al 2023;Zhang et al 2023) of kiwifruit have been carried out. However, functional genomic studies (Akagi et al 2019;Peng et al 2019;Fu et al 2021;Varkonyi-Gasic et al 2021;Wang et al 2022) are limited, partially because the genetic modification of kiwifruit is difficult and time-consuming.…”

Transcriptome Analysis Reveals Fruit Quality Formation in Actinidia eriantha Benth

“…A. eriantha ‘White’, A. eriantha ‘Shanong 18’, and A. eriantha ‘Ganmi 6’ are the dominant A. eriantha , and only one hybridized cultivar, A. eriantha ‘Jinyan’, has been registered. A. eriantha fruits are rich in Vc, minerals, and a variety of amino acids, with unique flavours [ 37 ]. Therefore, the synthesis and accumulation of vitamins, sugars, and organic acids during the growth and development process play a crucial role in the fruit quality and its unique flavour.…”