Amity Institute of Organic Agriculture, Amity University Uttar Pradesh, Noida, Uttar Pradesh, 201313, India.
Division of Seed Science and Technology, ICAR, Indian Agricultural Research Institute, Pusa, New Delhi, 110012, India.
Planta. 2023 May 22;258(1):3. doi: 10.1007/s00425-023-04159-3.
The consortium inoculation with strains R1 and R4 modified the root system to boost seedling growth, increase the zinc content of French bean pods, and reduce salinity stress. The present study demonstrated the effect of two 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase-producing plant growth-promoting rhizobacteria (Pantoea agglomerans R1 and Pseudomonas fragi R4) alone and consortia on the root system development, French bean growth, and zinc content as well as salinity stress tolerance. Both the strains were characterized for ACC utilization activity (426.23 and 380.54 nmol α-ketobutyrate mg protein h), indole acetic acid (IAA) production, phosphate solubilization, ammonia, hydrogen cyanide (HCN), and siderophore production. The strains exhibited zinc solubilization in both plate and broth assays with zinc oxide and zinc carbonate as zinc sources as validated by atomic absorption spectroscopy (AAS). Single or combined inoculations with the selected strains significantly modulated the architectural and morphological traits of the root system of French bean plants. Furthermore, the application of R1and R4 consortia has enhanced zinc content in roots (60.83 mg kg), shoots (15.41 mg kg), and pods (30.04 mg kg) of French bean plants grown in ZnCO amended soil. In another set of pot experiments, the consortium bacterization has significantly enhanced length as well as fresh and dry biomass of roots and shoots of the French bean plant under saline stress conditions. Additionally, inoculation with ACC-degrading rhizobacterial strains has increased chlorophyll and carotenoid contents, osmoprotectant content, and antioxidative enzyme (catalase and peroxidase) activity in comparison to their counterparts exposed to salt treatments only. Current findings suggested ACC deaminase-producing rhizobacterial strains hold the potential to improve root architecture which in turn promotes plant growth under salt-stressed conditions as well as enhances micronutrient concentration in host plants.
该联合体用菌株 R1 和 R4 进行接种，改变了根系结构，促进了幼苗生长，增加了菜豆荚的锌含量，并降低了盐胁迫。本研究证明了两种 1-氨基环丙烷-1-羧酸（ACC）脱氨酶产生植物促生根际细菌（聚生泛菌 R1 和脆性假单胞菌 R4）单独和联合体对根系发育、菜豆生长、锌含量以及耐盐性的影响。这两种菌株的 ACC 利用活性（426.23 和 380.54 nmol α-酮丁酸 mg 蛋白 h）、吲哚乙酸（IAA）生产、磷酸盐溶解、氨、氢氰酸（HCN）和铁载体生产均得到了表征。菌株在平板和肉汤试验中均显示出对氧化锌和碳酸锌作为锌源的锌溶解能力，原子吸收光谱法（AAS）验证了这一点。单独或联合接种所选菌株可显著调节菜豆植物根系的结构和形态特征。此外，R1 和 R4 联合体的应用提高了 ZnCO3 改良土壤中菜豆植物根系（60.83 mg kg）、茎（15.41 mg kg）和荚（30.04 mg kg）的锌含量。在另一组盆栽试验中，在盐胁迫条件下，联合体细菌化处理显著提高了菜豆植物根和茎的长度以及鲜重和干重。此外，与仅暴露于盐处理的对照相比，接种 ACC 降解根际细菌菌株可增加叶绿素和类胡萝卜素含量、渗透保护剂含量以及抗氧化酶（过氧化氢酶和过氧化物酶）活性。目前的研究结果表明，ACC 脱氨酶产生的根际细菌菌株有可能改善根系结构，从而在盐胁迫条件下促进植物生长，并提高宿主植物中的微量营养素浓度。
