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Thompson Seedless, a commonly grown table grape variety, is sensitive to salinity when grown on its own roots, and therefore, it is frequently grafted onto salinity-tolerant wild grapevine rootstocks. Rising soil salinity is a growing concern in irrigated agricultural systems. The accumulation of salts near the root zone severely hampers plant growth, leading to a decrease in the productive lifespan of grapevine and causing heavy yield losses to the farmer. In the present study, we investigated the differences in response to salinity between own-rooted Thompson Seedless (TSOR) and 110R-grafted Thompson Seedless (TS110R) grapevines, wherein 110R is reported to be a salt-tolerant rootstock. The grapevines were subjected to salt stress by treating them with a 150 mM NaCl solution. The stress-induced changes in protein abundance were investigated using a label-free shotgun proteomics approach at three timepoints viz. 6 h, 48 h, and 7 days of salt treatment. A total of 2793 proteins were identified, of which 246 were differentially abundant at various time-points in TSOR and TS110R vines. The abundance of proteins involved in several biological processes such as photosynthesis, amino acid metabolism, translation, chlorophyll biosynthesis, and generation of precursor metabolites was significantly affected by salt stress in both the vines but at different stages of stress. The results revealed that TSOR vines responded fervently to salt stress, while TS110R vines adopted a preventive approach. The findings of this study add to the knowledge of salinity response in woody and grafted plants and hence open the scope for further studies on salt stress-specific differences induced by grafting.

Three hundred and seventeen grape accessions from the National Active Grape Germplasm Site in India were analysed with 25 microsatellite markers. A total of 411 alleles were detected, of which 42% were rare alleles. Unique alleles for 56 genotypes were also identified. The analysis of microsatellite data identified 63 duplicate accessions and only 254 accessions were unique genotypes. Several cases of misnomers, synonymy and homonymy were identified. Parental genotype for a few clonal selections was ascertained. Population structure analysis grouped 254 unique genotypes into four major clusters. The analysis also revealed the presence of admixtures with only 79% of pure ancestry. A core collection comprising 80 genotypes was identified, which represented all the alleles and genetic diversity. A user-friendly and interactive computer application software was developed for storage and the retrieval of molecular data. A molecular database for the 254 genotypes was created. This analysis will help in the rationalization and better management of germplasm. Information on genetic diversity and population structure will form the basis for varietal improvement programmes.

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