内生细菌Pantoea alhagi NX-11及其胞外多糖对低温胁迫下水稻苗的促生效应  

Effects of endophytic bacterium Pantoea alhagi NX-11 and its extracellular polysaccharides on the growth of paddy rice seedlings under low temperature stress

作　　者：赵友学 杨燕波 朱宇峰 张国庆 薛听听 孙良 雷鹏[1,2] 徐虹 冯小海[2] 许宗奇 ZHAO You-xue;YANG Yan-bo;ZHU Yu-feng;ZHANG Guo-qing;XUE Ting-ting;SUN Liang;LEI Peng;XU Hong;FENG Xiao-hai;XU Zong-qi(College of Food and Light Industry,Nanjing Tech University,Nanjing 211816,China;Nanjing Xuankai Biotechnology Co.,Ltd.,Nanjing 210009,China)

机构地区：[1]南京工业大学食品与轻工学院,江苏南京211816 [2]南京轩凯生物科技股份有限公司,江苏南京210009

出　　处：《江苏农业学报》2022年第2期296-303,共8页Jiangsu Journal of Agricultural Sciences

基　　金：国家自然科学基金青年科学基金项目(3180011491);江苏省自然科学基金青年科学基金项目(BK20180158);国家级大学生创新创业计划项目(202110291010Z)。

摘　　要：以1株高产胞外多糖的内生细菌Pantoea alhagi NX-11为研究对象,通过构建的多糖分泌缺失菌株NX-11^(eps-)以及分离到的胞外多糖(EPS)纯品,研究菌株NX-11及其胞外多糖对低温胁迫下水稻苗的促生效应。结果表明,菌株NX-11显著缓解了低温胁迫导致的水稻苗茎长、根长、鲜质量、干质量和相对含水量的降低。对其作用机制研究发现,NX-11通过诱导水稻苗内抗氧化酶活性提高显著降低了低温胁迫对水稻苗的氧化伤害;通过增强水稻苗脂肪酸去饱和酶(FADS)活性,提高了膜脂的不饱和度和双键指数,增强了膜脂流动性;通过影响水稻苗的激素合成,进而增强水稻苗在低温胁迫环境下的调控能力,增强其低温耐受性。与NX-11相比,低温胁迫下,多糖分泌缺失的菌株NX-11^(eps-)对水稻苗的促生效应降低,而胞外多糖纯品表现出与NX-11一致的促生效果,表明NX-11胞外多糖在增强水稻苗低温耐受性的过程中发挥了关键作用。In this study,the endophytic bacterium Pantoea alhagi NX-11 with high extracellular polysaccharide production was used as the research object.The growth-promoting effects of strain NX-11 and its extracellular polysaccharides on rice seedlings under low temperature stress were studied by constructing polysaccharide secretion deficient strain NX-11^(eps-) and adding the isolated pure extracellular polysaccharide(EPS).The results showed that strain NX-11 significantly relieved the decrease of stem length,root length,fresh weight,dry weight and relative water content of rice seedlings caused by low temperature stress.The research on the action mechanism showed that,NX-11 significantly reduced the oxidative damage to rice seedlings under low temperature stress by inducing the increase of antioxidant enzyme activities in rice seedlings.The unsaturation degree and double bond index of membrane lipids were improved,and the fluidity of the membrane lipids was increased by enhancing the activity of the fattyacid desaturases(FADS)of the rice seedlings.The hormone synthesis of the rice seedlings was affected to enhance their regulation ability under the environment of low temperature stress,and to enhance their tolerance of low temperature.Compared with NX-11,under low temperature stress,the growth-promoting effect of polysaccharide secretion deficient strain NX-11^(eps-) to rice seedlings was reduced,while the pure exopolysaccharide showed the same growth-promoting effect as NX-11,suggesting that exopolysaccharide of NX-11 played a key role in enhancing the low temperature tolerance of rice seedlings.

关 键 词：Pantoea alhagi 水稻苗 胞外多糖 低温胁迫 低温耐受性 

分 类 号：S432.42[农业科学—植物病理学]