Multi-omics analysis revealed anthocyanin accumulation differences in purple tea plants ‘Ziyan’, ‘Zijuan’ and their dark-purple hybrid

Plant anthocyanins have many ecological functions and human health benefits. ‘Ziyan’ (ZY) and ‘Zijuan’ (ZJ) are well-known purple foliage tea cultivars representing two different varieties of Camellia sinensis; however, their anthocyanin profiles and crossbreeding potential are not well investigated. Here, we report the widely-targeted, anthocyanin-targeted metabolome and transcriptome analyses results of ZJ, ZY, and their hybrid ZZ that shows strong heterosis in foliage anthocyanin accumulation. A total of 417 differentially accumulated metabolites (DAM) were identified in widely-targeted analysis, and the DAM numbers of ZY_vs_ZJ, ZJ_vs_ZZ, ZY_vs_ZZ were 200, 197 and 137, respectively. Using the targeted ultraperformance liquid chromatography-tandem mass spectrometry analysis, we identified 22 anthocyanins with a concentration of ≥ 1 μg/g (dry weight) in the samples. The total anthocyanins in ZZ (4,574.78 μg/g dry weight) exceeded the combined content of its two parental cultivars. Delphinidin-3-O-galactoside was the most dominant anthocyanin. ZZ and ZJ accumulated more peonidin and petunidin anthocyanins than ZY. However, ZZ accumulated significantly lower catechin and proanthocyanin levels compared with ZY and ZJ, respectively. The transcriptional comparisons revealed that the selective up-regulation of CsANSs, CsGSTs may play critical roles in the anthocyanin heterosis of ZZ.