耐盐菌株筛选及其对盐胁迫下番茄种子萌发促进效应解析OA

[Objectives]This study aimed to isolate and screen bacteria that promote salt-tolerant growth of crops from the rhizosphere of halophytes in extreme desert environments,and to verify their growth-promoting effect on promoting salt-tolerant germination of tomato seeds under salt stress.[Methods]Collecting the root-zone soil of salt-tolerant plants in Qinghai desert,we initially screened 18 bacterial strains using dilution spread plate method and 16S rRNA sequencing.We then conducted a secondary screening by measuring plant growth-promoting indicators such as indole-3-acetic acid(IAA)production,iron chelation,phosphate and potassium solubilization,and salt tolerance.We conducted a seed germination test with tomato seeds under salt stress conditions and measured germination-related indicators,malondialdehyde(MDA)content,activities of various antioxidant enzymes to evaluate the seed germination promotion ability of the secondary screened strains.[Results]Seven bacterial strains screened,including Bacillus zhangzhouensis WXM-1,Bacillus zhangzhouensis WXM-13,Bacillus mobilis WXM-6,Dermacoccus barathri WXM-11,Microbacterium suaedae WXM-14,Sinomicrobium pectinilyticum WXM-15,and Planococcus rifietoensis WXM-17,were able to significantly improve the germination rate,germination potential,germination index,and root length of tomato seeds under 100 mmol·L-1 NaCl stress.These strains promoted salt-tolerant germination of tomato seeds by regulating the antioxidant enzyme system to reduce oxidative damage.[Conclusions]Seven strains with the potential to promote crop salt tolerance were obtained,among which Microbacterium suaedae and Sinomicrobium pectinilyticum were reported for the first time to have salt-tolerant plant growth-promoting functions.These seven strains had the prospect of being developed as functional microbial fertilizer strains and had the potential to be applied in agricultural saline soil improvement and crop production,helping to combine the"matching land to crops"and"matching crops to land"salt-alkali land comprehensive management model.