Sivankalyani Velu, Geetha Mahalingam, Subramanyam Kondeti, Girija Shanmugam
Plant Biotechnology Laboratory, Department of Biotechnology, Bharathiar University, Coimbatore, 641046, Tamil Nadu, India.
Transgenic Res. 2015 Apr;24(2):237-51. doi: 10.1007/s11248-014-9840-x. Epub 2014 Sep 27.
Cold is a major stress that limits the quality and productivity of economically important crops such as tomato (Solanum lycopersicum L.). Generating a cold-stress-tolerant tomato by expressing cold-inducible genes would increase agricultural strategies. Rare cold-inducible 2a (RCI2A) is expressed in Arabidopsis, but its molecular function during cold stress is not fully understood. Here we ectopically expressed Arabidopsis RCI2A in transgenic tomato to evaluate tolerance to cold stress without altering agronomic traits. Biochemical and physiological study demonstrated that expression of RCI2A in transgenic tomato enhanced the activity of peroxidase and ascorbate peroxidase (APX) and reduced the accumulation of H2O2, alleviated lipid peroxidation, increased the accumulation of chlorophyll, reduced chilling-induced membrane damage, retained relative water content and enhanced cold tolerance. A motif search revealed that the motifs of photosystem II (PSII) phosphoproteins PsbJ and PsbH and reaction-center proteins PsbL and PsbK were common to cold-inducible RCI2A and peroxidase proteins RCI3A, tomato peroxidase (TPX1), TPX2, tomato ascorbate peroxidase (APX1), and horseradish peroxidase (HRP-c). In addition to membrane protection, RCI2A may cross talk with PSII-associated proteins or peroxidase family enzymes in response to cold stress. Our findings may strengthen the understanding of the molecular function of RCI2A in cold-stress tolerance. RCI2A could be used to improve abiotic stress tolerance in agronomic crops.
低温是一种主要的胁迫因素，限制了番茄（Solanum lycopersicum L.）等重要经济作物的品质和产量。通过表达冷诱导基因培育耐低温胁迫的番茄将增加农业策略。拟南芥中表达稀有冷诱导蛋白2a（RCI2A），但其在低温胁迫期间的分子功能尚未完全了解。在此，我们在转基因番茄中异位表达拟南芥RCI2A，以评估其对低温胁迫的耐受性，同时不改变农艺性状。生化和生理学研究表明，转基因番茄中RCI2A的表达增强了过氧化物酶和抗坏血酸过氧化物酶（APX）的活性，减少了H2O2的积累，减轻了脂质过氧化，增加了叶绿素的积累，减少了冷诱导的膜损伤，保持了相对含水量并增强了耐寒性。基序搜索显示，光系统II（PSII）磷蛋白PsbJ和PsbH以及反应中心蛋白PsbL和PsbK的基序在冷诱导的RCI2A和过氧化物酶蛋白RCI3A、番茄过氧化物酶（TPX1）、TPX2、番茄抗坏血酸过氧化物酶（APX1）和辣根过氧化物酶（HRP-c）中是常见的。除了膜保护作用外，RCI2A可能在低温胁迫下与PSII相关蛋白或过氧化物酶家族酶发生相互作用。我们的研究结果可能会加强对RCI2A在耐低温胁迫中分子功能的理解。RCI2A可用于提高农作物对非生物胁迫的耐受性。
