两株耐盐碱大豆根瘤菌的分离及鉴定

Isolation and Identification of Two Strains of Saline-tolerant Soybean Rhizobium

为筛选适宜盐碱地条件下应用的根瘤菌菌株,本研究选择安达市采取土样,以大豆品种满仓金和绥农53作为宿主,对根瘤菌进行分离与纯化,筛选出两株具有典型根瘤菌表型特征的菌株,随后,对这些菌株进行16S rDNA测序分析,最终成功分离出2个根瘤菌菌株,并将它们命名为an28和an44。分别在各自捕获宿主上进行结瘤试验,来确定an28和an44的结瘤特征。抗生素抗性鉴定结果表明,an44对浓度20μg·mL^(-1)的红霉素(ERY)和浓度100μg·mL^(-1)的羧苄青霉素(CAR)具有抗性,an28对浓度50μg·mL^(-1)的ERY具有抗性。耐盐性鉴定结果表明,an28可以在NaCl浓度为600 mmol·L^(-1)的TY固体培养基上正常生长;而an44最高只能在NaCl浓度为200 mmol·L^(-1)时生长。耐碱性鉴定结果表明,an28可以在pH11.9的TY固体培养基上正常生长,而an44的碱性生长环境只能达到pH9.9。然后又分别在8种耐盐碱大豆种质(庆特4号、铁丰8号、牛眼睛、黑珍珠、齐农5号、合丰50、黑河49和黑农531)和2份不耐盐碱大豆品种(锦农5号和双宝8号)上分别接种2株根瘤菌进行结瘤鉴定,结果表明接种根瘤菌an28和an44在10个大豆种质上的结瘤数目变化范围分别为2.00~8.67和5.67~35.67个·株-1。

In order to screen suitable rhizobia strains for application under saline alkali soil conditions,this study selected soil samples from Anda City and used soybean varieties Mancangjin and Suinong 53 as hosts to isolate and purify rhizobia.Two strains with typical rhizobia phenotype characteristics were screened.Subsequently,16S rDNA sequencing analysis was performed on these strains,and two rhizobia strains were successfully isolated,named an28 and an44.Perform nodulation experiments on each captured host to determine the nodulation characteristics of an28 and an44.The results of antibiotic resistance identification showed that an44 was resistant to erythromycin(ERY)at a concentration of 20μg·mL^(-1)and carbenicillin(CAR)at a concentration of 100μg·mL^(-1),while an28 was resistant to ERY at a concentration of 50μg·mL^(-1).The salt tolerance identification results showed that an28 can grow normally on TY solid culture medium with a NaCl concentration of 600 mmol·L^(-1);And an44 can only grow at a maximum NaCl concentration of 200 mmol·L^(-1).The results of alkali resistance identification indicate that an28 can grow normally on TY solid culture medium at pH11.9,while the alkaline growth environment of an44 can only reach pH9.9.Then,two strains of rhizobia were inoculated on eight salt alkali tolerant soybean germplasms(Qingte 4,Tiefeng 8,Niuyanjing,Heizhenzhu,Qinong 5,Hefeng 50,Heihe 49,and Heinong 531)and two salt alkali tolerant soybean varieties(Jinnong 5 and Shuangbao 8)for nodulation identification.The results showed that the range of nodulation numbers for inoculating rhizobia an28 and an44 on 10 soybean germplasms was 2.00-8.67 and 5.67-35.67 per plant,respectively.