Department of Biochemistry and Molecular Biology, Hajee Mohammad Danesh Science and Technology University, Dinajpur, 5200, Bangladesh.
Department of Biological Sciences, College of Arts and Sciences, Carlow University, 3333 Fifth Avenue, Pittsburgh, PA, 15213, USA.
Arch Microbiol. 2023 May 10;205(6):231. doi: 10.1007/s00203-023-03564-2.
Endophytic biostimulant with pesticide bioremediation activities may reduce agrochemicals application in rice cultivation. The present study evaluates diazinon-degrading endophytic bacteria, isolated from rice plants grown in the fields with pesticide amalgamation, leading to increased productivity in high-yielding rice plants. These endophytes showed capabilities of decomposing diazinon, confirmed by FT-IR spectra analysis. Growth promoting activities of these endophytes can be attributed to their abilities to produce an increased level of IAA content and to demonstrate high level ACC-deaminase activities. Furthermore, these endophytes demonstrated enhanced level of extracellular cellulase, xylanase, amylase, protease and lignin degrading activities. Five genera including Enterobacter, Pantoea, Shigella, Acinetobacter, and Serratia, are represented only by the leaves, while four genera such as Enterobacter, Escherichia, Kosakonia, and Pseudomonas are represented only by the shoots. Five genera including, Klebsiella, Enterobacter, Pseudomonas, Burkholderia, and Bacillus are represented only by the roots of rice plants. All these strains demonstrated cell wall hydrolytic enzyme activities, except pectinase. All treatments, either individual strains or consortia of strains, enhanced rice plant growth at germination, seedling, vegetative and reproductive stages. Among four (I-IV) consortia, consortium-III generated the maximum rice yield under 70% lower doses of urea compared to that of control (treated with only fertilizer). The decoded genome of Klebsiella sp. HSTU-F2D4R revealed nif-cluster, chemotaxis, phosphates, biofilm formation, and organophosphorus insecticide-degrading genes. Sufficient insecticide-degrading proteins belonging to strain HSTU-F2D4R had interacted with diazinon, confirmed in molecular docking and formed potential catalytic triads, suggesting the strains have bioremediation potential with biofertilizer applications in rice cultivation.
具有农药生物修复活性的内生生物刺激素可能会减少水稻种植中农用化学品的应用。本研究评估了从田间施药合并导致高产水稻增产的水稻植物中分离出的具有降解二嗪磷能力的内生细菌。这些内生菌通过 FT-IR 光谱分析证实了其降解二嗪磷的能力。这些内生菌的促生长活性可归因于其产生更高水平的 IAA 含量和表现出高水平 ACC 脱氨酶活性的能力。此外，这些内生菌表现出增强的胞外纤维素酶、木聚糖酶、淀粉酶、蛋白酶和木质素降解酶活性。只有叶片代表五个属，包括肠杆菌属、泛菌属、志贺氏菌属、不动杆菌属和沙雷氏菌属，而只有茎部代表四个属，包括肠杆菌属、大肠杆菌属、小梨形菌属和假单胞菌属。只有水稻根部代表五个属，包括克雷伯氏菌属、肠杆菌属、假单胞菌属、伯克霍尔德氏菌属和芽孢杆菌属。所有这些菌株均表现出细胞壁水解酶活性，但果胶酶除外。所有处理，无论是单一菌株还是菌株混合物，都在萌发、幼苗、营养和生殖阶段增强了水稻植株的生长。在四个（I-IV）混合物中，与对照（仅用肥料处理）相比，混合物-III 在 70%较低剂量的尿素下产生了最大的水稻产量。克雷伯氏菌 HSTU-F2D4R 的解码基因组显示 nif 簇、趋化性、磷酸盐、生物膜形成和有机磷杀虫剂降解基因。属于 HSTU-F2D4R 株的足够杀虫剂降解蛋白与二嗪磷相互作用，在分子对接中得到证实，并形成潜在的催化三联体，表明这些菌株具有生物修复潜力，并可在水稻种植中作为生物肥料应用。
