Identification of Cell Wall and Carbon Metabolism Associated Changes in Autotetraploid Grapevine Through Phenotypic, Transcriptomic and Metabolomic Analyses

Abstract

Polyploidization can generate morphological and physiological variation in plants, but the molecular basis underlying leaf trait changes after genome doubling in grapevine remains insufficiently understood. This study aimed to characterize phenotypic, physiological, transcriptomic, and metabolomic differences between diploid and induced autotetraploid plants of ‘Thompson Seedless’ and to identify biological processes potentially associated with the observed leaf trait variation. In this study, autotetraploid plants were induced from axillary buds of ‘Thompson Seedless’ using colchicine treatment, and ploidy levels were confirmed by flow cytometry and chromosome counting. Phenotypic, physiological, transcriptomic, and metabolomic analyses were performed to compare diploid and tetraploid plants. Compared with diploids, tetraploids exhibited enlarged leaves, reduced plant stature, larger but less dense stomata, increased chloroplast number in guard cells, and higher total chlorophyll and carotenoid contents. Fv/Fm remained unchanged, whereas increased Vj and decreased ψEo and φEo suggested differences in electron transport-related characteristics beyond QA. Transcriptomic analysis identified 1564 differentially expressed genes, and metabolomic profiling detected 618 differentially accumulated metabolites. Integrated analyses highlighted coordinated molecular differences associated mainly with cell-wall processes, secondary metabolism, redox-related functions, and carbon-related pathways. These findings identify candidate biological processes for future functional validation and provide a basis for evaluating the potential value of autotetraploid germplasm in grapevine breeding.