祁连山高寒草地扁蓿豆和黄花棘豆耐冷PGPB的筛选及促生特性研究  

Screening and Promoting Effects of Cold-adapted PGPB from Melissitus ruthenica and Oxytropis ochrocephala Grown in the Alpine Grassland of Qilian Mountains

作　　者：李明源 王继莲 姚拓[1] 王振龙 张惠荣 柴加丽 刘晓婷 李青璞 LI Ming-Yuan;WANG Ji-Lian;YAO Tuo;WANG Zhen-Long;ZHANG Hui-Rong;CHAI Jia-Li;LIU Xiao-Ting;LI Qing-Pu(College of Grassland Science/Key Laboratory of Grassland Ecosystem of Ministry of Education,Gansu Agricultural University,Lanzhou 730070,China;The College of Life and Geographic Sciences/Key Laboratory of Biological Resources and Ecology of Pamirs Plateau in Xinjiang Uygur Autonomous Region,Kashi University,Kashi 844006,China)

机构地区：[1]甘肃农业大学草业学院/草业生态系统教育部重点实验室,兰州730070 [2]喀什大学生命与地理科学学院/新疆帕米尔高原生物资源与生态自治区重点实验室,喀什844006

出　　处：《农业生物技术学报》2021年第11期2074-2086,共13页Journal of Agricultural Biotechnology

基　　金：国家重点研发计划(2019YFC0507703)。

摘　　要：耐冷的植物促生菌(plant growth-promoting bacteria,PGPB)对于研制在低温环境下应用的微生物菌肥具有重要意义。为获得具有耐低温能力的PGPB资源,本研究采用选择性培养基在15℃下从祁连山高寒草地2种优势豆科植物扁蓿豆(Melissitus ruthenica)和黄花棘豆(Oxytropis ochrocephala)根际和根内筛选固氮、解磷菌株,并定量分析菌株的固氮、解磷、分泌吲哚-3-乙酸(IAA)、合成铁载体和1-氨基环丙烷-1-羧酸(l-aminocyclopropane-l-carboxylic acid,ACC)脱氨酶等促生特性。结合16S rRNA的限制性片段长度多态性PCR技术(PCR-restriction fragment length polymorphism,PCR-RFLP)与16S rRNA基因测序方法进行菌种鉴定,并挑选促生性能突出的优良菌株接种祁连山退化天然草地补播主要牧草品种—垂穗披碱草(Elymus nutans)幼苗,验证其对垂穗披碱草在低温下生长的影响。结果共筛选到87株PGPB,其中45株在4℃仍有促生活性,所有菌株分属5个菌属,以假单胞菌属(Pseudomonas)占绝对优势,兼具2种以上促生功能的占63.22%。接种不同功能特性的PGPB对垂穗披碱草的地下部分(根长,根表面积,平均根直径,根尖数,根干重)和地上部分(株高,茎粗,茎干重)均表现出一定促生效果,接种固氮菌株和分泌IAA菌株的促生效果最突出。本研究筛选到的耐冷PGPB菌种资源具备在高寒地区农牧业生产中开发应用的潜力,对研制适用于青藏高原退化草地修复的微生物菌肥有重要意义。Plant growth-promoting bacteria(PGPB)with low-temperature tolerance are beneficial for developing biofertilizers used in cold environments.To obtain cold-adapted PGPB resources,strains with nitrogen fixation and phosphorus solubilization abilities were screened from 2 leguminous species,Melissitus ruthenica and Oxytropis ochrocephala,which are the dominant leguminous plants grown in the alpine grasslands of Qilian Mountains.They were isolated from the root and rhizosphere of plants using selected medium.Other growth-promoting characteristics,including secretion of indole-3-acetic acid(IAA),production of siderophores and ACC deaminase,were further studied by qualitative and quantitative methods.16 S rRNA PCR-restriction fragment length polymorphism(PCR-RFLP)and 16 SrRNA gene sequencing were used to identify the strains.Then the excellent strains were selected to verify their effects on Elymus nutans at low temperatures.Elymus nutans are the main reseeding forage specie of natural grassland in this area.As a result,a total of 87 isolates were screened,of which 45 strains still exert high activity at 4℃.The inorganic phosphate solubility was negatively correlated with pH.The lower the pH was,the greater the inorganic phosphate solubility,but there was no linear relationship.The genetic diversity of PGPB in the rhizosphere and root of the two legumes was not rich.They were divided into 5 genera by 16 S rRNA gene sequencing and phylogenetic analysis,of which Pseudomonas were the dominant genera,and 63.22%of them had two or more plant growth-promoting characteristics.The inoculation of Elymus nutans.with cold-adapted PGPB possessing different functional characteristics had a significant promoting effect on both the development of root system(root length,root average diameter,root surface area,root dry weight,and the number of root tips)and aboveground parts(aboveground stem height,stem diameter,and stem dry weight),especially the nitrogenfixing and IAA secreting strains.The cold-adapted PGPB have potential applicatio

关 键 词：植物促生菌(PGPB) 耐冷 分离 祁连山 高寒草地 

分 类 号：S182[农业科学—农业基础科学] Q939.96[生物学—微生物学]