Investigation of the Regulation of Drought Tolerance by the SIHVA22I Gene in Tomato
Plants inevitably face a multitude of abiotic stresses during their growth and development stages.Drought stress significantly hampers crop growth and reduces yield.The plant HVA22 protein is characterized by the TB2/DP1 structural domain and is implicated in the modulation of plant growth,development,and responses to abiotic stress.However,its precise function in the context of drought stress response in tomato remains to be elucidated.Therefore,in this study,we investigated the functional role of the tomato SIHVA22I gene in drought tolerance.The results showed that the amino acid sequence of SIHVA22I exhibits a higher degree of sequence similarity to that of homologous HVA22I proteins found in other dicotyledonous plants.Furthermore,the expression pattern analysis revealed a significant upregulation of the SIHVA22I gene in response to drought stress and phytohormones(ABA and MeJA).Moreover,the function of the SIHVA22I gene in drought tolerance was subsequently verified by yeast heterologous expression and silencing of the endogenous SIHVA22I gene in tomato via virus-induced gene silencing.The silenced plants exhibited higher H2O2 and malondialdehyde contents,as well as lower O2-·scavenging after drought treatment.Moreover,the activities of superoxide dismutase,peroxidase,catalase,and ascorbate peroxidase were significantly decreased in the silenced plants compared to those in the control plants.Collectively,these results indicate that the SIHVA22I gene plays an important role in tomato resistance to drought stress.