摘要
盐碱胁迫是制约植物生长发育的主要非生物胁迫之一。植物内生细菌可通过提高渗透调节物质含量及抗氧化酶活性,增强植物的抗逆性。【目的】从盐碱地生长的紫花苜蓿根系中筛选并鉴定耐盐碱内生细菌,评价其耐盐碱能力、促生特性以及在盐碱环境下对紫花苜蓿生长的影响和定殖情况。【方法】采用组织匀浆法分离紫花苜蓿根系耐盐碱内生菌,通过形态学观察、16S rRNA基因序列系统发育树分析和生理生化实验对菌株进行鉴定;分析菌株的多种促生特性,并通过温室盆栽试验评价其对盐碱环境下紫花苜蓿生长的影响;利用绿色荧光蛋白(green fluorescent protein,GFP)标记内生菌,结合激光扫描共聚焦显微镜观察,评价菌株Z-1在紫花苜蓿根内的定殖情况。【结果】从盐碱地生长的紫花苜蓿根系中分离出1株摩拉维亚假单胞菌(Pseudomonas moraviensis)Z-1,其耐盐碱能力可达NaCl 4%、pH 9.0,并具有产1-氨基环丙烷-L-羧酸(1-aminocyclopropane-L-carboxylic acid,ACC)脱氨酶、嗜铁素、吲哚-3-乙酸(indole-3-acetic acid,IAA)和溶磷能力;在盐碱环境下,接种Z-1能够显著提高紫花苜蓿地上部分的干重、根系活力和可溶性蛋白含量;显著提高过氧化氢酶(catalase,CAT)、过氧化物酶(peroxidase,POD)和超氧化物歧化酶(superoxide dismutase,SOD)活性,使过氧化氢(hydrogen peroxide,H2O_(2))、超氧阴离子(superoxide anion,O_(2)-)和丙二醛(malondialdehyde,MDA)含量显著降低(P<0.05);Z-1在紫花苜蓿根内具有良好的定殖能力,定殖量可达7.57×10^(4)CFU/g。【结论】耐盐碱内生细菌Z-1在促进紫花苜蓿生长以及提高其抗盐碱能力方面发挥了重要作用,是开发紫花苜蓿耐盐碱微生物制剂的优质菌株资源。
Saline-alkali stress is one of the main abiotic constraints limiting plant growth and development.Endophytic bacteria can enhance the stress tolerance of host plants by increasing osmotic adjustment substances and boosting antioxidant enzyme activities.[Objective]To isolate and identify saline-alkali tolerant endophytic bacteria from the roots of alfalfa grown in salinealkali soil and evaluate them regarding the saline-alkali tolerance,plant growth-promoting traits,effects on alfalfa growth under saline-alkali stress,and colonization.[Methods]Saline-alkali tolerant endophytes were isolated by the tissue homogenization method from alfalfa roots.Strains were identified by morphological observation,16S rRNA gene-based phylogenetic analysis,and physiological and biochemical assays.Multiple plant growth-promoting traits were assayed in vitro.A greenhouse pot experiment was conducted to assess the effect of the selected strain on alfalfa growth under saline-alkali conditions.Colonization of strain Z-1 in alfalfa roots was visualized by green fluorescent protein tagging and laser scanning confocal microscopy.[Results]Pseudomonas moraviensis Z-1 was successfully isolated from the roots of alfalfa growing in salinealkali soil.The endophytic bacterial strain tolerated 4%NaCl and pH 9.0 and displayed the ability to produce 1-aminocyclopropane-L-carboxylate deaminase,siderophores,indole-3-acetic acid,and soluble phosphorus.Under saline-alkali conditions,inoculation with Z-1 significantly increased the dry weights of the aboveground parts,root vigor,and soluble protein content of alfalfa.Moreover,the strain significantly increased catalase,peroxidase,and superoxide dismutase activities and decreased the hydrogen peroxide,superoxide anion,and malondialdehyde content(P<0.05).Confocal microscopy confirmed successful colonization of Z-1 in alfalfa roots at 7.57×10^(4)CFU/g.[Conclusion]The saline-alkali tolerant endophytic bacterium Z-1 plays a vital role in promoting alfalfa growth and enhancing its tolerance to saline-alkali stress.It represents a promising candidate for developing microbial preparations to ameliorate saline-alkali soil.
作者
郑慧颖
唐璐
张静
史怡梦
姚琳
刘建生
陈佳欣
郭长虹
ZHENG Huiying;TANG Lu;ZHANG Jing;SHI Yimeng;YAO Lin;LIU Jiansheng;CHEN Jiaxin;GUO Changhong(Heilongjiang Provincial Key Laboratory of Molecular Cellular Genetics and Genetic Breeding,College of Life Science and Technology,Harbin Normal University,Harbin,Heilongjiang,China;Heilongjiang Guohong Energy Conservation and Environmental Protection Co.,Ltd.,Harbin,Heilongjiang,China)
出处
《微生物学报》
北大核心
2025年第8期3317-3330,共14页
Acta Microbiologica Sinica
基金
国家自然科学基金(U21A20182)
黑龙江省科技攻关项目(2021ZXJ03B05)
哈尔滨师范大学研究生创新基金(HSDSSCX2024-14)。
关键词
紫花苜蓿
盐碱环境
内生细菌
促生
定殖
alfalfa
saline-alkali conditions
endophytic bacteria
plant growth-promoting
colonization
