过表达ApGSMT2和ApDMT2基因的拟南芥和玉米耐盐性分析

对照植株，说明过表达ApGSMT2和ApDMT2基因对于提高拟南芥的耐盐性具有显著效果。进一步对T2代转基因玉米株系幼苗的耐盐性进行试验，结果表明，180 mmol/L NaCl处理后，未转基因对照植株萎蔫，而转基因株系长势良好，其株高、根长、叶片相对含水量和鲜重显著高于对照，说明过表达ApGSMT2和ApDMT2基因显著提高了玉米对盐胁迫的耐受性，为利用基因工程技术创制玉米耐盐种质提供了理论依据。

关键词：玉米;拟南芥;ApGSMT2;ApDMT2;甘氨酸甜菜碱;耐盐性

中图分类号：S513.034+Q949.748.306  文献标识号：A  文章编号：1001-4942（2019）06-0010-07

Abstract Maize is a moderately sensitive crop to soil salinization and is vulnerable to saline-alkali damage. Glycine betaine （GB）， as a major osmotic protective solute， has shown the ability to improve plant resistance to a variety of abiotic stresses， such as salinity， drought and low temperature. Two methyltransferase genes， ApGSMT2 and ApDMT2， which are involved in the synthesis of GB， were cloned from Aphanothece halophytica in our previous studies. The two genes were overexpressed in Arabidopsis and maize through Agrobacterium-mediated method， and the transgenic positive strains were obtained. The T2 generation was obtained through selfing-cross from T1 generation. With the T2 seeds of Arabidopsis as materials， the germination test was conducted by setting the treatments of 0， 50， 100， 150 and 200 mmol/L NaCl. The germination rate of transgenic Arabidopsis seeds was significantly higher than that of wild-type plants under various concentrations of salt treatment. It indicated that overexpressing ApGSMT2 and ApDMT2 could significantly enhance the salt tolerance of Arabidopsis. The test was further conducted on the salt tolerance of T2 maize seedlings. Under the treatment of 180 mmol/L NaCl， the transgenic maize seedlings developed better， while the control plants wilting. The plant height， root length， leaf relative water content and fresh weight of transgenic lines were significantly higher than those of untransformed control plants. These results demonstrated that ApGSMT2 and ApDMT2 overexpression significantly increased the tolerance of Arabidopsis and maize to salt stress.

Keywords Maize; Arabidopsis; ApGSMT2;ApDMT2; Glycine betaine; Salt tolerance

土壤鹽渍化是造成作物减产的主要因素之一[1]。玉米既是重要的粮食和饲料作物，又可作为医药和工业原料。由于玉米属于中度盐敏感植物，耐盐能力比较低，因此其种植面积和产量受到一定的限制[2， 3]。随着生物技术的迅速发展，利用基因工程技术培育转基因玉米已成为提高玉米耐盐性和解决其在盐碱化土壤上种植的有效途径之一[4， 5]。