番茄类囊体膜磷脂酰甘油不饱和脂肪酸缓解低温下PSII光抑制
首发时间:2011-06-24
摘要:番茄叶绿体甘油三磷酸酰基转移酶基因(LeGPAT)的过表达增加了类囊体膜磷酸甘油(PG)不饱和脂肪酸含量。低温胁迫下,与野生型(WT)相比,转正义LeGPAT株系具有较高的超氧化物歧化酶(SOD)和抗坏血酸过氧化物酶(APX)的活性,低的O2 和H2O2含量和电解质外渗率,光合放氧活性下降速度慢,而转反义LeGPAT株系下降较快。转正义基因植株能够维持较高的PSII最大光化学效率(Fv/Fm)和较高的D1蛋白含量,而用蛋白合成抑制剂硫酸链霉素(SM)处理后,其Fv/Fm水平和D1蛋白含量却明显少于另外两个株系。上述结果表明,低温胁迫下PG不饱和脂肪酸含量的增加提高了D1蛋白的修复速率,降低膜的伤害度,提高抗氧化酶的活性,进而提高番茄植株的耐冷性。
关键词: 低温胁迫 D1蛋白 叶绿体甘油-3-磷酸酰基转移酶 磷脂酰甘油 番茄
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The unsaturation of phosphatidylglycerol in tomato thylakoid membrane alleviates PSII photoinhibition under chilling stress
Abstract:Overexpression of chloroplastic glycerol-3-phosphate acyltransferase gene (LeGPAT) in tomato increased cis-unsaturated fatty acid content in phosphatidylglycerol (PG) of thylakoid membrane. Under chilling stress, the oxygen evolving activity, the maximal photochemical efficiency of PSII (Fv/Fm), superoxide dismutase (SOD) and ascorbate peroxidae (APX) activities decreased less in sense lines than in antisense lines compared with wild type (WT) plants. The relative electric conductivity, O 2 and H2O2 contents in sense lines were lower than those of WT and antisense lines. The antisense lines with low level of unsaturated fatty acids in PG were extremely susceptible to photoinhibition of PSII and had a significant reduction in the D1 protein content of PSII reaction center under chilling stress. However, in the presence of streptomycin (SM), the degradation of D1 protein was faster in sense lines than that in WT and antisense plants. These results suggested that, under chilling stress, increasing cis-unsaturated fatty acids in PG by overexpression of LeGPAT can alleviate PSII photoinhibition by accelerating the repair of D1 protein and improving the activity of antioxidant enzymes in chloroplasts.
Keywords: chilling stress D1 protein glycerol-3-phosphate acyltransferase phosphatidylglycerol tomato
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番茄类囊体膜磷脂酰甘油不饱和脂肪酸缓解低温下PSII光抑制
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