Characterization of mercury ameliorating rhizobacteria for enhancing growth and yield of Triticum Aestivum L. in the field: An in-vitro and in- silico study

IF 2.7 3区生物学 Q2 PLANT SCIENCES

South African Journal of Botany Pub Date : 2024-10-15 DOI:10.1016/j.sajb.2024.09.071

Aatif Amin , Muhammad Naveed , Sunbul Rasheed , Zakia Latif , Tariq Aziz , Fahad Al Asmari , Maha Aljabri

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引用次数: 0

Abstract

Mercury (Hg) resistant and indole 3-acetice acid (IAA)-producing rhizobacteria were isolated from mercury-contaminated areas. Among the 60 Hg-resistant bacterial isolates, three were selected based on high Hg-resistance (MIC-30 µg/ml) and IAA production (15–40 µg/ml). Selected isolates were subjected to biochemical and molecular characterization, and High-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC–MS) analyses were performed to confirm IAA production by these rhizobacteria. Pot and field experiments were conducted under controlled conditions on Triticum aestivum L. with a bacterial consortium consisting of AZ-3, Z-A15, and Z-A22. The selected isolates were identified as Bacillus cereus AZ-3, Enterobacter cloacae Z-A15, and Pseudomonas putida Z-A22, respectively. B. cereus AZ-3 showed 90 % resistance against HgCl₂ at 40 µg/ml due to the presence merT gene. E. cloacae Z-A15 and P. putida Z-A22 showed high production of IAA at 20 and 36 µg/ml respectively. High-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC–MS) confirmed IAA production by the selected bacteria. In greenhouse experiments, the inoculation of T. aestivum L. with bacterial consortium A7 (AZ-3, Z-A15, and Z-A22) with Hg resulted in 35 %, 60 %, 22 %, 98 % and 100 % increase while without Hg showed 32 %, 60 %, 30 %, 56 %, and 120 % increase in shoot length, tillers, spike length, number of spikelets, and seed weight/200 g respectively. In field experiments, the A7 showed 17 %, 66 %, 17 %, 27 %, 40 % and 70 % increases in shoot length, tillers, spike length, number of spikelets, dry weight and yield/acre in T. aestivum L. respectively (p < 0.05). The structural determination of MerT protein of B. cereus AZ-3 was carried out using bioinformatics tools, i.e., DISOPRED, SwissModel, ERRAT, Verify3D and PROCHECK. These tools predicted the structural-based functional homology of MerT transmembrane protein in bacterial Hg-detoxification system. The use of the bacterial consortium A7 as a biofertilizer to reduce mercury pollution while promoting plant growth in contaminated soils offers a novel approach to maintaining sustainable agricultural land in polluted environments.

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为提高田间小麦生长和产量而确定汞改良根瘤菌的特性：体外和体内研究

从汞污染地区分离出了耐汞（Hg）并能产生吲哚-3-乙酸（IAA）的根瘤菌。在 60 个抗汞细菌分离物中，根据高抗汞性（MIC-30 µg/ml）和 IAA 产量（15-40 µg/ml）选出了 3 个。对筛选出的分离株进行了生化和分子鉴定，并进行了高效液相色谱（HPLC）和气相色谱-质谱（GC-MS）分析，以确认这些根瘤菌产生了 IAA。在受控条件下，使用由 AZ-3、Z-A15 和 Z-A22 组成的细菌群对 Triticum aestivum L.进行了盆栽和田间试验。经鉴定，所选分离物分别为蜡样芽孢杆菌 AZ-3、肠杆菌 Z-A15 和假单胞菌 Z-A22。由于含有 merT 基因，蜡样芽孢杆菌 AZ-3 在 40 µg/ml 浓度下对氯化汞的抗性为 90%。E. cloacae Z-A15 和 P. putida Z-A22 分别在 20 微克/毫升和 36 微克/毫升的浓度下显示出较高的 IAA 产量。高效液相色谱法（HPLC）和气相色谱-质谱法（GC-MS）证实了所选细菌的 IAA 产量。在温室实验中，接种含汞细菌群 A7（AZ-3、Z-A15 和 Z-A22）后，T. aestivum L.的芽长、分蘖、穗长、小穗数和种子重量/200 克分别增加了 35%、60%、22%、98% 和 100%；而不接种含汞细菌群 A7 后，芽长、分蘖、穗长、小穗数和种子重量/200 克分别增加了 32%、60%、30%、56% 和 120%。在田间试验中，A7 对 T. aestivum L.的芽长、分蘖、穗长、小穗数、干重和每英亩产量分别增加了 17%、66%、17%、27%、40% 和 70%（p <0.05）。利用生物信息学工具，即 DISOPRED、SwissModel、ERRAT、Verify3D 和 PROCHECK，对 B. cereus AZ-3 的 MerT 蛋白进行了结构测定。这些工具预测了 MerT 跨膜蛋白在细菌汞解毒系统中基于结构的功能同源性。利用细菌群 A7 作为生物肥料来减少汞污染，同时促进受污染土壤中植物的生长，为在污染环境中保持农业用地的可持续发展提供了一种新方法。

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来源期刊

South African Journal of Botany 生物-植物科学

CiteScore

5.20

自引率

9.70%

发文量

709

审稿时长

61 days

期刊介绍： The South African Journal of Botany publishes original papers that deal with the classification, biodiversity, morphology, physiology, molecular biology, ecology, biotechnology, ethnobotany and other botanically related aspects of species that are of importance to southern Africa. Manuscripts dealing with significant new findings on other species of the world and general botanical principles will also be considered and are encouraged.