Department of Bioengineering and Biotechnology, Birla Institute of Technology, Mesra, Ranchi, Jharkhand, India.
Department of Biological Sciences, Birla Institute of Technology & Science, Pilani, Rajasthan.
PLoS One. 2022 May 6;17(5):e0267127. doi: 10.1371/journal.pone.0267127. eCollection 2022.
Plant growth promoting rhizobacterium (PGPR) designated as ZNP-4, isolated from the rhizosphere of Ziziphus nummularia, was identified as Enterobacter cloacae following 16S rRNA sequence analysis. The isolated strain exhibited various plant growth promoting (PGP) traits. The 1-aminocyclopropane-1-carboxylic acid deaminase (ACCD) activity was evaluated under diverse physiological conditions that could be useful for minimizing the abiotic stress-induced inhibitory effects on wheat plants. The strain showed resistance to salt (NaCl) and metal (ZnSO4) stress. The effect of E. cloacae ZNP-4 on the augmentation of plant growth was studied under salinity stress of 150 mM (T1 treatment) & 200 mM (T2 treatment) NaCl. The inoculation of strain ZNP-4 significantly improved the various growth parameters of wheat plant such as shoot length (41%), root length (31%), fresh weight (28%), dry weight (29%), photosynthetic pigments chlorophyll a (62%) and chlorophyll b (34%). Additionally, the strain was found to be efficient for minimizing the imposed Zn stress in terms of improving plant growth, biomass and photosynthetic pigments in pots containing different levels of metal stress of 150 mg kg-1 (treatment T1) and 250 mg kg-1 (treatment T2). Isolate ZNP-4 also improved the proline content and decreased malondialdehyde (MDA) level under both salinity and metal stress, therefore maintaining the membrane integrity. Furthermore, bacterial inoculation increased the activities of antioxidative enzymes such as superoxide dismutase (SOD), catalase (CAT), and peroxidase (POX). The positive effects of PGPR occurred concurrently with the decrease in abiotic stress-induced reactive oxygen species (ROS) molecules such as hydrogen peroxide (H2O2) and superoxide (O2-) contents. Overall, the observed results indicate that use of bacteria with such beneficial traits could be used as bio-fertilizers for many crops growing under stress conditions.
从酸枣根际分离到的一株具有促生作用的植物根际细菌（PGPR），经 16S rRNA 序列分析鉴定为阴沟肠杆菌（Enterobacter cloacae）。该分离菌株表现出多种植物促生（PGP）特性。在不同的生理条件下评估了 1-氨基环丙烷-1-羧酸脱氨酶（ACCD）活性，这对于减轻非生物胁迫对小麦植株的抑制作用可能是有用的。该菌株表现出对盐（NaCl）和金属（ZnSO4）胁迫的抗性。在 150mM（T1 处理）和 200mM（T2 处理）NaCl 盐胁迫下，研究了阴沟肠杆菌 ZNP-4 对植物生长的增强作用。接种该菌株可显著提高小麦植株的各种生长参数，如茎长（41%）、根长（31%）、鲜重（28%）、干重（29%）、光合色素叶绿素 a（62%）和叶绿素 b（34%）。此外，该菌株在提高植物生长、生物量和光合色素方面对减轻施加的 Zn 胁迫也很有效，在含有不同金属胁迫水平的盆中，150mgkg-1（处理 T1）和 250mgkg-1（处理 T2）。分离株 ZNP-4 还可在盐胁迫和金属胁迫下提高脯氨酸含量，降低丙二醛（MDA）水平，从而保持膜的完整性。此外，细菌接种可提高超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和过氧化物酶（POX）等抗氧化酶的活性。PGPR 的积极作用与非生物胁迫诱导的活性氧（ROS）分子如过氧化氢（H2O2）和超氧阴离子（O2-）含量的降低同时发生。总的来说，观察到的结果表明，使用具有这种有益特性的细菌可以作为在胁迫条件下生长的许多作物的生物肥料。
