Isolation and identification of soybean rhizobium Y63 strain
Giving full play to symbiotic nitrogen fixation in soybean production is important in reducing nitro-gen fertilizer application,increasing the activity of soil microorganisms,ensuring the health of arable land and agro-ecosystems,and promoting the sustainable development of green agriculture.In this study,the high-yielding,high-quality,multi-resistant and widely adapted soybean variety Zhongdou 63 was used as the capture host,and soybean rhizobium Y63 was isolated and identified from a high-yielding demonstration field in Honghu City,Hubei Prov-ince.The strains with the apparent characteristics of rhizobia were screened by using plate scribing and BTB reac-tion test,and the 16S rDNA sequences were amplified and a phylogenetic tree was constructed to identify two soy-bean rhizobia strains,both named Y63-1 and Y63-2,as rhizobia from a single nodule of Zhongdou 63.The antibiot-ic resistance analysis showed that Y63-1 was resistant to Carbenicillin(Car),Cefotaximesodium(Cef),Ampicillin(Amp)and Rifampin(Rif),and Y63-2 was resistant to kanamycin(kan),Carbenicillin(Car)and Ampicillin(Amp),Rifampin(Rif).Finally,the two rhizobia Y63-1 and Y63-2 were inoculated in pots at certain ratios with the slow-growing rhizobium 113-2 and the fast-growing rhizobium HH103 as controls,and the fresh weight of above-ground parts,the number of nodules and the dry weight of nodules of Zhongdou 63 were statistically analyzed at 42 and 51 days after inoculation.The results showed that Y63-1∶Y63-2=2∶1 had the best nodulation effect when inoculated with Zhongdou 63.The preliminary identification of the proportion of Y63-1 and Y63-2 in the nodules after mixed inoculation showed that Y63-1 was the dominant rhizobium,consistent with the nodulation phenotype.This study enriches the rhizobial resources in China,and the results provide a theoretical basis for the application of mixed rhi-zobial inoculation techniques in soybean production,as well as a theoretical basis for incising the yield potential of Zhongdou 63 and other varieties through inoculation with highly efficient rhizobia in production.
soybeanZhongdou 63rhizobiumisolation and identificationnodule symbiosis