Characterization and Early Response of the DEAD Gene Family to Heat Stress in Tomato

The DEAD-box RNA helicase family, acting as a critical regulator in RNA metabolism, plays a vital role in plant growth, development, and adaptation to various stresses. Although a number of DEAD proteins have been reported to participate in heat stress response in several species, the response of DEAD-box RNA helicases to heat stress has not been comprehensively analyzed in tomato. In this study, 42 SlDEAD genes were identified from the tomato genome. Evolutionary analysis of DEAD family genes across different plant species reveals that DEAD family genes can be segregated into five groups. A comprehensive analysis of their physicochemical properties, gene structure, chromosome location, and conserved motifs unveils diversity among the members of the SlDEAD family. An investigation into the subcellular localization of seven SlDEAD proteins indicates that SlDEAD7, SlDEAD14, and SlDEAD26 are located in the endoplasmic reticulum, and SlDEAD40 is located in the endoplasmic reticulum and nucleus, whereas SlDEAD17, SlDEAD25, and SlDEAD35 are located in the chloroplast. The expression of 37 out of 42 SlDEAD genes was responsive to heat stress induction. During the early stage of high-temperature treatment, they exhibited five distinct expression patterns. These findings contribute to a deeper comprehension of the evolution, expansion complexity, and function of SlDEAD genes and provide insights into the potential role of SlDEAD genes in tomato tolerance to heat stress.