Identification and expression analysis of carotenoid biosynthesis genes in tomato solanum lycopersicum l

Abstract

Carotenoids play essential roles in photosynthetic complexes, antioxidant defense, coloration, and other functions across multiple plant tissues. In tomatoes, salinity stress negatively impacts vegetative organ development and productivity, yet it may enhance fruit color and taste, presenting an agricultural challenge. This study aimed to investigate the responses of ten tomato genotypes to control and varying levels of salinity stress (50mM, 100mM, and 150 mM) by analysing morpho-physiological, biochemical, and molecular characteristics. In silico approaches were employed to analyse key enzymes encoding genes involved in carotenoid biosynthesis in tomato, utilizing template plants such as Arabidopsis and Potato. Thirty-four carotenoid genes were identified, with their nucleotide sequences subjected to regulatory sequence analyses. Domain structure analysis revealed highly conserved catalytic domains in carotenoid biosynthesis enzymes across tomato, Potato, and Arabidopsis. Phylogenetic analysis with Arabidopsis and characterized carotenoid biosynthesis genes highlighted homologous genes and duplicated gene copies potentially adopting new functions. This study assessed differential expression patterns of carotenoid pathway genes, including phytoene synthase, lycopene and#946;-cyclase, and and#946;-carotene hydroxylase, across salt-tolerant (Pusa Ruby), moderate-tolerant (Arka Samrat), and sensitive (Punjab Ratta) tomato varieties under varying NaCl concentrations. Semi-quantitative real PCR expression data indicated decreased expression of phytoene synthase and increased expression of lycopene and#946;-cyclase and and#946;-carotene hydroxylase with rising salt concentrations. Understanding carotenoid biosynthesis genes in tomatoes can inform breeding programs aimed at developing improved, carotenoid-rich varieties, addressing agricultural challenges. Key words: Tomato, Salt stress, gene expression, carotenoid. newline