冻土荒漠区分离低温适生PGPR菌的鉴定及其抗菌促生特性

对分离自青海昆仑山口冻土荒漠区植被根围的7株可在4及10℃低温条件下正常生长的低温适生菌进行鉴定分析，并检测其拮抗病原菌活性及催芽促生特性。综合理化测定、BOX-PCR 及 ERIC-PCR 指纹图谱分析、16S rDNA及基因gyrB序列鉴定结果，其中6株菌株为简单芽孢杆菌Bacillus simplex，1株菌株为B. malacitensis。平板对峙试验表明，7株菌株对油菜菌核病原菌Sclerotinia sclerotiorum及水稻白叶枯病原菌 Xanthomonas oryzae pv. oryzae 具有显著拮抗效果。以菌株 KLD2（B. simplex）及 KLD5（B. malacitensis）发酵菌液处理玉米种子及拟南芥幼苗，结果表明菌株发酵液可明显促进种子萌发及幼苗生长，其鲜重、根长、须根数等表征均有显著增加。几株低温适生PGPR（plant growth promoting rhizobacteria）芽孢杆菌具备抗菌、催芽及促生特性，具有农业应用潜力。

Identification of Low-temperature Adapting PGPR Strains Isolated from Frozen Desert Area and Their Antimicrobial and Growth-promoting Activity

Seven low-temperature adapting Bacillus strains growing under 4-10 ℃ were isolated from plant rhizospher soil in frozen desert of Kunlun Mountain. Identification via biochemistry, BOX-PCR, ERIC-PCR fingerprint, 16S rDNA sequence and gyrB sequence showed that six strains were B. simplex, while the other one was B. malacitensis. Tests on antimicrobial and growth-promoting activities indicated that they presented obvious antagonism against both Sclerotinia sclerotiorum and Xanthomonas oryzae pv. Oryzae, two important plant pathogens. Furthermore, strain KLD2 （B. simplex） and KLD5 （B. malacitensis） were demonstrated to be highly capable to increase root length, fibrous root quantity, fresh weight and seed germination of both Arabidopsis thaliana and maize . This study indicated that these low-temperature adapting Bacillus PGPR strains are of high potential for application in agriculture.