Institute of Environment and Sustainable Development, Banaras Hindu University, Varanasi 221005, Uttar Pradesh, India.
Division of Research Environment, Ministry of Environment, Forest and Climate Change, Indira Paryavaran Bhawan, New Delhi, India.
Microbiol Res. 2021 Jan;242:126616. doi: 10.1016/j.micres.2020.126616. Epub 2020 Oct 9.
Rice (Oryza sativa L.) growth and productivity has been negatively affected due to high soil salinity. However, some salt-tolerant plant growth-promoting bacteria (ST-PGPB) enhance crop growth and reduce the negative impacts of salt stress through regulation of some biochemical, physiological, and molecular features. Total thirty six ST-PGPB were isolated from sodic soil of eastern Uttar Pradesh, India, and screened for salt tolerance at different salt (NaCl) concentrations up to 2000 millimolar (mM). Out of thirty-six, thirteen strains indicated better growth and plant growth properties (PGPs) in NaCl amended medium. Among thirteen, one most effective Bacillus pumilus strain JPVS11 was molecularly characterized, which showed potential PGPs, such as indole-3-acetic acid (IAA),1-aminocyclo propane-1-carboxylicacid (ACC) deaminase activity, P-solubilization, proline accumulation and exopolysaccharides (EPS) production at different concentrations of NaCl (0 -1200 mM). Pot experiment was conducted on rice (Variety CSR46) at different NaCl concentrations (0, 50, 100, 200, and 300 mM) with and without inoculation of Bacillus pumilus strain JPVS11. At elevated concentrations of NaCl, the adverse effects on chlorophyll content, carotenoids, antioxidant activity was recorded in non-inoculated (only NaCl) plants. However, inoculation of Bacillus pumilus strain JPVS11 showed positive adaption and improve growth performance of rice as compared to non-inoculated in similar conditions. A significant (P < 0.05) enhancement plant height (12.90-26.48%), root length (9.55-23.09%), chlorophyll content (10.13-27.24%), carotenoids (8.38-25.44%), plant fresh weight (12.33-25.59%), and dry weight (8.66-30.89%) were recorded from 50 to 300 mM NaCl concentration in inoculated plants as compared to non-inoculated. Moreover, the plants inoculated with Bacillus pumilus strain JPVS11showed improvement in antioxidant enzyme activities of catalase (15.14-32.91%) and superoxide dismutase (8.68-26.61%). Besides, the significant improvement in soil enzyme activities, such as alkaline phosphatase (18.37-53.51%), acid phosphatase (28.42-45.99%), urease (14.77-47.84%), and β-glucosidase (25.21-56.12%) were recorded in inoculated pots as compared to non-inoculated. These results suggest that Bacillus pumilus strain JPVS11 is a potential ST-PGPB for promoting plant growth attributes, soil enzyme activities, microbial counts, and mitigating the deleterious effects of salinity in rice.
由于土壤盐分过高，水稻（Oryza sativa L.）的生长和生产力受到了负面影响。然而，一些耐盐植物促生菌（ST-PGPB）通过调节一些生化、生理和分子特征，促进作物生长并减轻盐胁迫的负面影响。
从印度东部北方邦的苏打土中分离出 36 株耐盐植物促生菌（ST-PGPB），并在不同盐（NaCl）浓度下（高达 2000 毫摩尔（mM））筛选其耐盐性。在 36 株中，有 13 株在添加 NaCl 的培养基中表现出更好的生长和植物生长特性（PGPs）。在这 13 株中，一株最有效的解淀粉芽孢杆菌 JPVS11 进行了分子鉴定，该菌株表现出潜在的 PGPs，如吲哚-3-乙酸（IAA）、1-氨基环丙烷-1-羧酸（ACC）脱氨酶活性、P 溶解、脯氨酸积累和胞外多糖（EPS）的产生，在不同浓度的 NaCl（0-1200mM）下。
在不同的 NaCl 浓度（0、50、100、200 和 300mM）下，在水稻（品种 CSR46）上进行了盆栽实验，同时接种和不接种解淀粉芽孢杆菌 JPVS11。在高浓度的 NaCl 下，未接种（仅 NaCl）植物的叶绿素含量、类胡萝卜素、抗氧化活性受到了不利影响。然而，与未接种的植物相比，接种解淀粉芽孢杆菌 JPVS11 表现出了积极的适应能力，并改善了水稻的生长表现。
从 50 到 300mM NaCl 浓度下，接种植物的株高（12.90-26.48%）、根长（9.55-23.09%）、叶绿素含量（10.13-27.24%）、类胡萝卜素（8.38-25.44%）、植物鲜重（12.33-25.59%）和干重（8.66-30.89%）均有显著提高（P<0.05）。此外，接种解淀粉芽孢杆菌 JPVS11 的植物的过氧化氢酶（15.14-32.91%）和超氧化物歧化酶（8.68-26.61%）的抗氧化酶活性也得到了改善。此外，与未接种的土壤相比，接种解淀粉芽孢杆菌 JPVS11 的土壤中碱性磷酸酶（18.37-53.51%）、酸性磷酸酶（28.42-45.99%）、脲酶（14.77-47.84%）和β-葡萄糖苷酶（25.21-56.12%）等土壤酶活性均有显著提高。
这些结果表明，解淀粉芽孢杆菌 JPVS11 是一种潜在的耐盐植物促生菌，可促进植物生长特性、土壤酶活性、微生物数量，并减轻盐胁迫对水稻的有害影响。
