C. G. Bhakta Institute of Biotechnology, Uka Tarsadia University, Maliba Campus, Bardoli, Surat, Gujarat, 394 350, India.
Department of Biosciences, Veer Narmad South Gujarat University, Surat, Gujarat, India.
Arch Microbiol. 2020 May;202(4):887-894. doi: 10.1007/s00203-019-01801-1. Epub 2020 Jan 1.
In this study, chromium (Cr)-tolerant bacteria were test for their efficiency in alleviating Cr stress in Cicer arietinum plants. On the basis of 16S rRNA gene analysis, the isolates were identified belonging to genus Stenotrophomonas maltophilia, Bacillus thuringiensis B. cereus, and B. subtilis. The strains produced a considerable amount of indole-3-acetic acid in a medium supplemented with tryptophan. The strains also showed siderophore production (S2VWR5 and S3VKR17), phosphorus production (S1VKR11, S3VKR2, S3VKR16, and S2VWR5), and potassium solubilization (S3VKR2, S2VWR5, and S3VKR17). Furthermore, the strains were evaluated in pot experiments to assess the growth promotion of C. arietinum in the presence of chromium salts. Bacterization improved higher root and shoot length considerably to 6.25%-60.41% and 11.3%-59.6% over the control. The plants also showed increase in their fresh weight and dry weight in response to inoculation with Cr-tolerant strains. The accumulation of Cr was higher in roots compared to shoots in both control and inoculated plants, indicating phytostabilization of Cr by C. arietinum. However, phytostabilization was found to be improved manifold in inoculated plants. Apart from the plant attributes, the amendment of soil with Cr and Cr-tolerant bacteria significantly increased the content of total chlorophyll and carotenoids, suggesting the inoculant's role in protecting plants from deleterious effects. This work suggests that the combined activity of Cr-tolerant and plant growth-promoting (PGP) properties of the tested strains could be exploited for bioremediation of Cr and to enhance the C. arietinum cultivation in Cr-contaminated soils.
在这项研究中，测试了耐铬细菌缓解鹰嘴豆植物中铬胁迫的效率。根据 16S rRNA 基因分析，分离出的菌株属于寡养单胞菌属、苏云金芽孢杆菌、蜡状芽孢杆菌。这些菌株在添加色氨酸的培养基中产生了相当数量的吲哚-3-乙酸。这些菌株还表现出铁载体生产（S2VWR5 和 S3VKR17）、磷生产（S1VKR11、S3VKR2、S3VKR16 和 S2VWR5）和钾溶解（S3VKR2、S2VWR5 和 S3VKR17）。此外，还在盆栽试验中评估了这些菌株，以评估在铬盐存在下鹰嘴豆生长的促进作用。细菌化显著提高了根和芽的长度，分别比对照提高了 6.25%-60.41%和 11.3%-59.6%。与对照相比，接种耐铬菌株的植物还表现出鲜重和干重的增加。在对照和接种植物中，铬在根部的积累高于在芽部，表明铬被鹰嘴豆固定。然而，在接种植物中，发现植物固定铬的能力有了显著提高。除了植物属性外，用铬和耐铬细菌改良土壤显著增加了总叶绿素和类胡萝卜素的含量，表明接种剂在保护植物免受有害影响方面的作用。这项工作表明，耐铬和植物生长促进（PGP）特性的测试菌株的联合活性可用于铬的生物修复，并提高在铬污染土壤中鹰嘴豆的种植。
