4株促紫花苜蓿生长的芽孢杆菌分子鉴定及其生物活性分析  

Molecular Identification and Bioactivity Analysis of Four Bacillus Strains Promoting the Growth of Alfalfa

作　　者：陈兰 谢永丽 吴晓晖[1] 杨雪 王添 武玲玲 CHEN Lan;XIE Yongli;WU Xiaohui;YANG Xue;WANG Tian;WU Lingling(State Key Laboratory of Plateau Ecology and Agriculture,Qinghai University,Xining 810016,China;College of Agriculture and Animal Husbandry,Qinghai University,Xining 810016,China)

机构地区：[1]青海大学省部共建三江源生态与高原农牧业国家重点实验室,西宁810016 [2]青海大学农牧学院,西宁810016

出　　处：《西北农业学报》2023年第2期212-221,共10页Acta Agriculturae Boreali-occidentalis Sinica

基　　金：国家自然科学基金(32160030);青海省科技厅项目(2018-HZ-813);青海大学三江源生态与高原农牧业国家重点实验室自主课题(2019-ZZ-12)。

摘　　要：通过菌悬液(浓度为1×107 cfu/mL)灌根试验,测定分离自青海乌兰荒漠沙地白刺(Nitraria tangutorum)根际的4株芽孢杆菌(Bacillus)菌株WL81、WL911、WL92和WL99对紫花苜蓿(Medicago sativa)的促生效果。采用平板对峙法、透明圈法、CMC-Na法分别检测菌株拮抗、固氮及降解纤维素活性,对菌株耐盐及低温适生性进行测定,利用16S rDNA及gyrB基因序列对菌株进行分子鉴定。结果表明,4株菌株对紫花苜蓿幼苗生长均具有显著促生效果。菌株WL911对禾谷镰孢(Fusarium graminearum)、锐顶镰孢(F.acuminatum)、链格孢(Alternaria alternata)、黑曲霉(Aspergillus niger)具有显著拮抗效果(抑菌圈直径>15 mm)。4株菌株在改良阿须贝无氮固体培养基上均产生透明圈(透明圈直径≥20 mm),表现出一定的固氮能力。4株菌株均具有显著降解纤维素活性。菌株WL911、WL92和WL99可耐受0.13 kg/L的盐浓度、4℃低温,表现出一定的耐盐性及耐低温性。菌株WL81、WL911、WL92和WL99分别鉴定为短小芽孢杆菌(Bacillus pumilus)、贝莱斯芽孢杆菌(B.velezensis)、蜡样芽孢杆菌(B.cereus)及萎缩芽孢杆菌(B.atrophaeus)。这4株优良芽孢杆菌菌株在高原植被恢复、畜牧业发展中具有一定的应用潜力。The growth-promoting effect of four Bacillus strains WL81,WL911,WL92 and WL99 that isolated from the rhizosphere of Nitraria tangutorum from the desert of Wulan in Qinghai province was evaluated by irrigation on root of alfalfa(Medicago sativa)with their strain suspension(1×107 cfu/mL of cell concentration).Antagonistic activity,nitrogen fixation ability and cellulose degradation activity were detected by methods of plate confrontation,clear zone and CMC-Na respectively.Salt-tolerance and low-temperature tolerance of these four strains were also detected.Species of the four strains were identified using molecular method based on 16S rDNA and gyrB gene sequences analyses.The results showed that the effect of the four strains on the growth of alfalfa seedlings were significant.The strains WL911 presented distinct antagonistic activity to Fusarium graminearum,F.acuminatum,Alternaria alternata and Aspergillus niger(inhibition zone in diameter>15 mm).The four strains showed certain nitrogen fixation ability with clear zone(diameter≥20 mm)on modified Ashby nitrogen-free solid medium and with apparent cellulose degradation activity.The strains WL911,WL92 and WL99 presented special salt-tolerance and low-temperature tolerance,which can grow in a concentration of 0.13 kg/L NaCl solution and in low-temperature condition of 4℃.Based on sequence comparison and phylogenetic tree analysis,the four strains of WL81,WL911,WL92 and WL99 were identified as Bacillus pumilus,B.velezensis,B.cereus,B.atrophaeus,respectively.All of four Bacillus spp.strains have a potential of application prospect in plateau vegetation restoration and animal husbandry development.

关 键 词：促紫花苜蓿生长 芽孢杆菌 拮抗 固氮 降解纤维素 分子鉴定 

分 类 号：S541.9[农业科学—作物学]