Genome-wide identification of light-harvesting chlorophyll a/b-binding (LHC) gene family in tomato and functional analysis of SlLhcb1.11 and SlELIP1 under cold stress

Light-harvesting chlorophyll a/b-binding (LHC) proteins, as the antenna complex, collect and transfer light energy to the reaction centers of PSII. They are crucial for abiotic stress responses, especially in the photoprotection under cold stress. However, members of the LHC gene family in tomato (Solanum lycopersicum L.) have not yet been identified. In this study, a total of 39 SlLHC proteins containing the chlorophyll a/b binding domain or light-harvesting-like domain were identified, and classified into four subfamilies: Lhc, Lil, PsbS, and FCII. Further qRT-PCR analysis showed SlLhcb1.11 was inhibited and SlELIP1 was induced at low temperature (4 °C). Subsequently, the result of VIGS experiment showed that silencing SlLhcb1.11 or SlELIP1 genes resulted in lighter leaf color, reduced chlorophyll content, compromised photosynthesis, and decreased cold tolerance in tomato plants. These findings offer novel insights into the structure and function of SlLHC genes, thereby contributing to genetic resources for the development of cold-tolerant tomato germplasm.