小麦钙调素类似基因TaCML1介导植株抵御干旱逆境能力及生理机制研究

almodulin-like proteins (CMLs), which participate in decoding calcium signals by binding calcium ions, playing critical roles in regulating plant growth and development and mediating plant tolerance to various abiotic stresses. This study focused on TaCML1, a calmodulin-like protein gene identified through drought-stressed wheat transcriptome analysis, to investigate its biological functions and physiological mechanisms in mediating drought stress resistance. The TaCML1 gene has a full length of 858 bp, containing a 504 bp open reading frame (ORF) that encodes 167 amino acid residues. The encoded protein possesses three EF-hand conserved domains involved in calcium ion binding. At the nucleotide level, TaCML1 exhibits high homology with its orthologous genes in Aegilops, wild emmer wheat (Triticum dicoccoides), and Brachypodium distachyon. Under drought stress, the expression level of TaCML1 in wheat roots was enhanced, suggesting its involvement in responding to drought signaling at the transcriptional level. Analyses of TaCML1 transgenic lines under drought stress revealed that, compared to wild-type (WT) plants, the TaCML1-overexpressing lines showed enhanced growth, increased plant dry mass, accelerated stomatal closure rate, improved photosynthetic carbon assimilation capacity suuc as elevated net photosynthetic rate (Pn), chlorophyll content (SPAD), stomatal conductance (gs), transpiration rate (Tr), and photosystem II photochemical efficiency (ΦPSⅡ], increased cellular osmotic adjustment substance content, enhanced activities of cell protective enzymes (SOD, POD, and CAT), and decreased malondialdehyde (MDA) content. In contrast, the TaCML1 antisense lines displayed weakened growth, reduced plant dry mass, delayed stomatal closure rate, diminished photosynthetic carbon assimilation capacity, decreased osmotic adjustment substance content, and reduced activities of cell protective enzymes under drought stress. In summary, the up-regulated expression of TaCML1 exerts a significant regulatory role in mediating plant drought resistance by modulating stomatal movement, enhancing leaf photosynthetic carbon assimilation capacity, promoting synthesis and metabolism of osmotic adjustment substances, and reducing cellular reactive oxygen species accumulation.