两类新疆狗牙根抗旱基因型抗氧化酶保护系统及其基因表达差异分析  

Analysis of antioxidant enzyme protection systems and gene expression differences in two Xinjiang bermudagrass genotypes with contrasting drought resistance

作　　者：曾令霜 李培英[1,2] 孙宗玖 孙晓梵[1] ZENG Ling-shuang;LI Pei-ying;SUN Zong-jiu;SUN Xiao-fan(Department of Pratacultural and Environmental Science,Xinjiang Agricultural University,Urumqi 830052,China;Xinjiang Key Laboratory of Grassland Resources and Ecology,Urumqi 830052,China)

机构地区：[1]新疆农业大学草业与环境科学学院,新疆乌鲁木齐830052 [2]新疆草地资源与生态重点实验室,新疆乌鲁木齐830052

出　　处：《草业学报》2022年第7期122-132,共11页Acta Prataculturae Sinica

基　　金：国家自然科学基金项目(31960362)资助。

摘　　要：新疆狗牙根具发达的根状茎和细长的匍匐茎,在耐旱性方面表现出广泛的遗传变异特性,对抗旱型C138和不抗旱型C32狗牙根两个基因型进行自然干旱7 d后复水3 d处理,明确2个基因型在干旱胁迫及复水下抗氧化酶系统生理响应及基因表达水平上的差异。结果表明:干旱胁迫降低了狗牙根草坪表观质量、叶片相对含水量和叶绿素含量,电导率及丙二醛(malondialdehyde,MDA)含量升高,且C32较C138下降或升高更为明显。随干旱时间延长,狗牙根体内超氧阴离子自由基(O_(2))、过氧化氢(H_(2)O_(2))、MDA含量均显著上升,且C32较C138升高更显著,而超氧化物歧化酶(superoxide dismutase,SOD)、过氧化物酶(peroxidase,POD)和过氧化氢酶(catalase,CAT)活性呈先升后降趋势,抗坏血酸过氧化物酶(ascorbate peroxidase,APX)活性呈增加趋势。抗旱型C138对比不抗旱型C32表现为SOD、POD、APX、DHAR和GPX等抗氧化基因高水平的表达,而不抗旱型C32较C138表现出高的脂质过氧化和低的抗氧化酶活性及基因表达水平;在复水过程中,POD活性在提高抗氧化能力及清除活性氧(reactive oxygen species,ROS)过程中起着至关重要的作用。干旱胁迫诱导抗氧化酶及其相关基因上调表达,增强了细胞内的抗氧化防御能力,有助于狗牙根维持细胞膜稳定性,延缓叶片的脱水,从而提高了狗牙根的抗旱能力。Xinjiang bermudagrass ecotypes have well-developed rhizomes and slender stolons,and exhibit extensive genetic variation in drought tolerance.In this study drought tolerant(C138)and drought-sensitive(C32)bermudagrass genotypes were exposed to natural drought for 7 days followed by 3 days of rehydration treatment and the differences in physiological response and gene expression levels of the antioxidant enzyme systems under drought stress and rehydration were evaluated.It was found that drought stress reduced the apparent quality of bermudagrass lawn,relative leaf water content and chlorophyll content,increased electrical conductivity and malondialdehyde(MDA)content,and these responses were expressed more significantly in C32 than in C138.With increased duration of drought exposure,the levels of O_(2),H_(2)O_(2),and MDA in bermudagrass leaves increased significantly,and C32 increased more significantly than C138,while activities of superoxide dismutase(SOD),peroxidase(POD)and catalase(CAT)initially increased and then decreased,and ascorbate peroxidase(APX)activities increased.Drought-resistant C138 and non-drought-resistant C32 showed high-levels of expression of antioxidant genes such as SOD,POD,APX,DHAR and GPX,while non-drought-resistant C32 showed the highest lipid peroxidation and the lowest antioxidant enzyme activity and gene expression levels.In the process of rehydration,POD activity plays a vital role in improving antioxidant capacity and removing reactive oxygen species.Drought stress induces the up-regulation of the expression of antioxidant enzymes and related genes,enhances the antioxidant defense in cells,helps bermudagrass maintain cell membrane stability,delays the dehydration of leaves,and improves the bermudagrass drought resistance ability.

关 键 词：干旱胁迫 狗牙根 抗氧化系统 基因表达 

分 类 号：S688.4[农业科学—观赏园艺]