GST genes as key regulators of redox balance in tomato: prospects for improved fruit quality and stress tolerance.

The cultivated tomato (Solanum lycopersicum L.) is one of the world's most important vegetable crops. However, environmental stresses can significantly diminish crop productivity and affect quality. Glutathione S-Transferases (GSTs) are a class of proteins primarily involved in detoxification and oxidative stress response. They are encoded by a complex gene family characterized by gene duplication. Previous studies on GST genes highlighted their potential to enhance stress tolerance and accumulation of antioxidant compounds. To expand the range of effective targets for breeding tomato, our research focused on the functional characterization of the tomato GSTome and its role in plant stress response. We carried out a bioinformatic survey of the GST gene family in the latest tomato genome annotation, identifying 90 members across various subclasses. Analysis of available RNA-seq datasets revealed the expression profiles of GST genes in different plant tissues and in response to environmental stresses. Previous QTL studies in our lab on a tomato introgression population identified several QTLs associated with the upregulation of GST genes and the fruit hyperaccumulation of antioxidants. The overexpression of a tomato GST gene increased tolerance to drought and salinity. Notably, a SNP variant of a tomato lambda GST gene associated with drought tolerance traits. This gene correlated with the expression of genes involved in photosynthetic electron transport and carbon assimilation in a drought-tolerant tomato cultivar. Currently, we are developing a library of tomato lines edited by CRISPR/Cas technology at various GST loci, to explore the GST genes potential in breeding crops for more resilient agroecosystems.