Advanced Post-Graduate Center, Lam, Guntur, Andhra Pradesh, 522034, India.
Acharya N.G, Ranga Agricultural University, Lam, Guntur, Andhra Pradesh, 522034, India.
Curr Microbiol. 2022 Sep 10;79(10):308. doi: 10.1007/s00284-022-03000-6.
The profile of endophytic bacteria in groundnut and their potential contribution to the reduction of drought stress are incompletely understood. Therefore, the current study is concentrated on examining the groundnut-culturable endophytic bacterial diversity, which has practical implications for reducing drought stress. Polyethylene glycol (PEG 6000) was used to identify the osmotic stress-tolerant bacterial isolates, and 51 strains were selected based on their tolerance. Fourteen potential bacterial strains with drought alleviation capacity and plant growth-promoting properties were selected and their identity was confirmed using 16S rRNA analysis. These isolates were positive for 1-aminocyclopropane-1-carboxylate deaminase, ammonia, minerals solubilization, and indole acetic acid. When applied to the groundnut seeds under water deficit conditions, the bacterial consortium (A. deltaense AMT1/Rhizobium sp. (N-Fixer) Caballeronia zhejiangensis BPT9 (PSB), Burkholderia dolosa BPT8 (KRB), and Bacillus safensis BPT6 (Drought-Mitigating Isolate)) increased the peanut germination by 91%. Soil application improved the aggregate formation. Further testing was carried out in the pot culture, where bacterial consortium improved the shoot length, root length, relative water content, chlorophyll content, nodule number, oil content, and kernel yield at 75% Water Holding capacity (WHC). Moreover, the treatment with bacterial consortia further stimulated the drought-protective mechanisms and resulted in higher efficiency of nitrogen, phosphorous, potassium uptake, electrolytes leakage, and soil enzymes such as dehydrogenase and alkaline phosphatase at 75% WHC. Microbial consortia inoculation controlled groundnut water absorption, photosynthetic performance, and stress metabolites, reducing drought-induced damage; hence, it is believed that endophytes have potential application in the improvement of yields of crops.
内生细菌在花生中的分布及其对减少干旱胁迫的潜在贡献尚不完全清楚。因此，本研究集中于研究花生可培养内生细菌多样性，这对于减轻干旱胁迫具有实际意义。聚乙二醇（PEG 6000）用于鉴定耐渗透胁迫的细菌分离株，根据其耐受性选择了 51 株。选择了 14 株具有抗旱能力和促进植物生长特性的潜在细菌菌株，并通过 16S rRNA 分析确认其身份。这些分离株对 1-氨基环丙烷-1-羧酸脱氨酶、氨、矿物质溶解和吲哚乙酸呈阳性。在水分亏缺条件下应用于花生种子时，细菌共生体（A. deltaense AMT1/Rhizobium sp.（N-Fixer）Caballeronia zhejiangensis BPT9（PSB）、Burkholderia dolosa BPT8（KRB）和 Bacillus safensis BPT6（Drought-Mitigating Isolate））将花生发芽率提高了 91%。土壤施用改善了团聚体的形成。在盆栽培养中进一步进行了测试，在 75%水分保持能力（WHC）下，细菌共生体提高了株高、根长、相对含水量、叶绿素含量、根瘤数、油含量和核仁产量。此外，细菌共生体处理进一步刺激了干旱保护机制，在 75%WHC 下提高了氮、磷、钾的吸收效率、电解质渗漏和土壤酶如脱氢酶和碱性磷酸酶的效率。微生物共生体接种控制了花生的水分吸收、光合作用和应激代谢物，减轻了干旱引起的损伤；因此，人们认为内生菌具有提高作物产量的潜在应用。
