Jalal-Ud-Din Sabahet, Elahi Nosheen Noor, Mubeen Fathia
Institute of Botany, Bahauddin Zakariya University, Multan, Pakistan.
Soil and Environmental Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE-C, PIEAS), Faisalabad, Pakistan.
Front Microbiol. 2024 Sep 27;15:1446064. doi: 10.3389/fmicb.2024.1446064. eCollection 2024.
The present study was conducted with the aim to isolate, characterize, and identify the promising zinc-solubilizing rhizobacteria found naturally in the rhizosphere of canola ( L.) plants. The study investigated the roles of these strains in nutrient acquisition and assimilation of extracellular molecules such as hormones and secondary metabolites. Ten isolated promising zinc-solubilizing strains (CLS1, CLS2, CLS3, CLS6, CLS8, CLS9, CLS11, CLS12, CLS13, and CLS15) were selected and characterized biochemically. Almost all the tested strains were Gram-positive, could fix nitrogen, and were positive for indole acetic acid, HCN, exopolysaccharides, and siderophore production. These effective zinc-solubilizing strains were identified through 16S rRNA gene sequencing. Based on the amount of solubilized zinc and halo zone diameter, four potent strains (CLS1, CLS2, CLS3, and CLS9) were selected for pot and field evaluation. Among all the identified bacterial genera isolated from the rhizosphere of the same host plant at different sampling sites, was found most abundant and found at all three sampling sites. The strains , , and were found at two different sites. was found at only one site. These strains have a number of plant growth-stimulating characteristics as well as the ability to colonize plant roots successfully. The results indicated that inoculation of all these four zinc-solubilizing tested strains enhanced the plant growth, oil contents, and yield attributes of canola as compared to non-inoculated control with fertilizer levels. (CLS1) was first reported as a zinc solubilizer and associated with canola. (CLS2) and (CLS9) were found to be the best strains, with the most pronounced beneficial effect on canola growth and yield traits in both pot and field conditions. The site-specific dominance of these strains observed in this study may contribute toward decision-making for the development of specific inocula for canola. Therefore, identification of these strains could help in providing adequate amount of soluble zinc along with enhanced plant growth, yield, and oil content of canola.
本研究旨在分离、表征和鉴定在油菜（L.）植物根际自然发现的有前景的解锌根际细菌。该研究调查了这些菌株在营养获取以及激素和次生代谢物等细胞外分子同化中的作用。挑选出10株分离得到的有前景的解锌菌株（CLS1、CLS2、CLS3、CLS6、CLS8、CLS9、CLS11、CLS12、CLS13和CLS15）并进行生化表征。几乎所有测试菌株都是革兰氏阳性菌，能够固氮，并且吲哚乙酸、HCN、胞外多糖和铁载体产生呈阳性。通过16S rRNA基因测序鉴定这些有效的解锌菌株。根据溶解锌的量和晕圈直径，挑选出4株高效菌株（CLS1、CLS2、CLS3和CLS9）进行盆栽和田间评估。在不同采样地点从同一寄主植物根际分离出的所有已鉴定细菌属中，发现 最为丰富，且在所有三个采样地点均有发现。菌株 、 和 在两个不同地点被发现。 仅在一个地点被发现。这些菌株具有许多促进植物生长的特性以及成功定殖于植物根系的能力。结果表明，与未接种肥料水平的对照相比，接种所有这4株测试解锌菌株均提高了油菜的植株生长、油含量和产量属性。 （CLS1）首次被报道为解锌菌并与油菜相关。 （CLS2）和 （CLS9）被发现是最佳菌株，在盆栽和田间条件下对油菜生长和产量性状均具有最显著的有益影响。本研究中观察到的这些菌株的位点特异性优势可能有助于为油菜开发特定接种剂的决策制定。因此，鉴定这些菌株有助于提供适量的可溶性锌，同时提高油菜的植株生长、产量和油含量。
