Identification of candidate genes associated with albino phenotype in ‘Huangjinya’ tea plant through genome resequencing

Albino mutant tea tree is a germplasm resource with distinctive characteristics, having high amino acids and low tea polyphenol content, as well as significant ornamental value. Grasping the molecular underpinnings of ‘Huangjinya’ leucism is crucial for enhancing its quality consistency and boosting its production. Among the progeny of ‘Huangjinya,’ green and albino mutant plants were previously discovered. To pinpoint the genetic factors linked to the whitening trait in ‘Huangjinya’, whole-genome resequencing was conducted on two phenotypic groups: extreme albino mutant plants and extreme green mutant plants. Based on genome variation and gene annotation, CsPPR1 and CsPPR2 , pentatricopeptide repeat (PPR) protein family genes, were selected as candidate genes related to the albino phenotype. Cloning analysis confirmed that the protein sequences encoded by CsPPR1 and CsPPR2 in ‘Huangjinya’ and ‘Fuding Dabaicha’ have different amino acid residues. qRT-PCR validation showed that the relative expression levels of CsPPR1 and CsPPR2 in green mutant plants of the F1 progeny were higher than those in albino mutant plants, and their relative expression levels in ‘Fuding Dabaicha’were higher than in ‘Huangjinya.’ VIGS-mediated silencing of these genes induced photobleaching in the plants. Moreover, transient overexpression of these genes in ‘Huangjinya’ leaves increased chlorophyll content. Therefore, it was concluded that CsPPR1 and CsPPR2 are genes potentially linked to the ‘Huangjinya’ leucistic trait, which can assist in further exploration of the albinism mechanism. • Integrated multi-omics and functional validation to dissect the genetic basis of albino phenotype in ‘Huangjinya’ tea plant • First identified CsPPR1 and CsPPR2 as core candidate genes linked to the albino trait of ‘Huangjinya’ tea plant • Validated gene functions at physiological, subcellular and molecular levels, improving conclusion rigor • CsPPR1 / CsPPR2 provide molecular markers and breeding targets for albino tea cultivar improvement