Screening and Promoting Effects of Cold-adapted PGPB from Melissitus ruthenica and Oxytropis ochrocephala Grown in the Alpine Grassland of Qilian Mountains
LI Ming-Yuan1,2, WANG Ji-Lian1,2, YAO Tuo1,*, WANG Zhen-Long1, ZHANG Hui-Rong1, CHAI Jia-Li1, LIU Xiao-Ting1, LI Qing-Pu1
1 College of Grassland Science/Key Laboratory of Grassland Ecosystem of Ministry of Education, Gansu Agricultural University, Lanzhou 730070, China; 2 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
Abstract：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. 16S rRNA PCR-restriction fragment length polymorphism (PCR-RFLP) and 16S rRNA 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 16S 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 nitrogen-fixing and IAA secreting strains. The cold-adapted PGPB have potential applications for agriculture stock production of cold areas, which is of great significance to the development of microbial fertilizer suitable for the near-natural restoration of degraded alpine grasslands on the Qinghai-Tibet Plateau.
李明源, 王继莲, 姚拓, 王振龙, 张惠荣, 柴加丽, 刘晓婷, 李青璞. 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[J]. 农业生物技术学报, 2021, 29(11): 2074-2086.
LI Ming-Yuan, WANG Ji-Lian, YAO Tuo, WANG Zhen-Long, ZHANG Hui-Rong, CHAI Jia-Li, LIU Xiao-Ting, LI Qing-Pu. Screening and Promoting Effects of Cold-adapted PGPB from Melissitus ruthenica and Oxytropis ochrocephala Grown in the Alpine Grassland of Qilian Mountains. 农业生物技术学报, 2021, 29(11): 2074-2086.
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