Department of Biochemistry and Molecular Biology, Faculty of Biological Science, University of Dhaka, Dhaka, 1000, Bangladesh.
Department of Biochemistry and Molecular Biology, Faculty of Biological Science, University of Dhaka, Dhaka, 1000, Bangladesh.
Microbiol Res. 2018 Mar;208:43-53. doi: 10.1016/j.micres.2018.01.008.
Endophytes are bacterial or fungal organisms associated with plants in an obligate or facultative manner. In order to maintain a stable symbiosis, many of the endophytes produce compounds that promote plant growth and help them adapt better to the environment. This study was conducted to explore the potential of jute bacterial endophytes for their growth promotion ability in direct and indirect ways. A total of 27 different bacterial species were identified from different varieties of a jute plant (Corchorus olitorius) and different parts of the plant (leaf, root, seed, and seedling) based on 16S rRNA gene sequence. Two of the isolates showed ACC deaminase activity with Staphylococcus pasteuri strain MBL_B3 and Ralstonia solanacearum strain MBL_B6 producing 18.1 and 8.08 μM mg h α-ketobutyrate respectively while eighteen had the ACC deaminase gene (acdS). Fourteen were positive for siderophore activity while Kocuria sp. strain MBL_B19 (133.36 μg/ml) and Bacillus sp. strain MBL_B17 (124.72 μg/ml) showed high IAA production ability. Seven bacterial strains were able to fix nitrogen with only one testing positive for nifH gene. Five isolates exhibited phosphorus utilization ability with Bacillus sp. strain MBL_B17 producing 218.47 μg P/ml. Three bacteria were able to inhibit the growth of a phytopathogen, Macrophomina phaseolina and among them Bacillus subtilis strain MBL_B4 was found to be the most effective, having 82% and 53% of relative inhibition ratio (RIR) and percent growth inhibition (PGI) values respectively. Nine bacteria were tested for their in vivo growth promotion ability and most of these isolates increased seed germination potential and vigour index significantly. Bacillus subtilis strain MBL_B13 showed 26.8% more vigour index than the control in which no bacterial inoculum was used. All inoculants were found to increase the dry weight of jute seedlings in comparison to the control plants and the most increase in fresh weight was found for Staphylococcus saprophyticus strain MBL_B9. Staphylococcus pasteuri strain MBL_B3 exhibited diverse in vitro growth promotion activity and significant growth promoting effect in in vivo pot experiments. These bacterial strains with plant growth enhancing abilities have the potential to be used as bioinoculants.
内生菌是与植物以专性或兼性方式相关的细菌或真菌。为了维持稳定的共生关系,许多内生菌会产生促进植物生长和帮助其更好地适应环境的化合物。本研究旨在探索黄麻细菌内生菌在直接和间接方式下促进生长的潜力。根据 16S rRNA 基因序列,从不同品种的黄麻植物(Corchorus olitorius)和植物的不同部位(叶、根、种子和幼苗)中鉴定出 27 种不同的细菌物种。两种分离物显示 ACC 脱氨酶活性,葡萄球菌巴氏亚种 MBL_B3 和茄科雷尔氏菌 MBL_B6 分别产生 18.1 和 8.08 μM mg h α-酮丁酸,而 18 种具有 ACC 脱氨酶基因(acdS)。14 种具有铁载体活性,而 Kocuria sp. 菌株 MBL_B19(133.36 μg/ml)和芽孢杆菌属菌株 MBL_B17(124.72 μg/ml)表现出较高的 IAA 产生能力。有 7 种细菌能够固定氮,只有一种测试出 nifH 基因呈阳性。有 5 种分离物具有利用磷的能力,芽孢杆菌属菌株 MBL_B17 产生 218.47 μg P/ml 的磷。有 3 种细菌能够抑制植物病原菌 Macrophomina phaseolina 的生长,其中芽孢杆菌属菌株 MBL_B4 的相对抑制率(RIR)和相对生长抑制率(PGI)值分别为 82%和 53%。有 9 种细菌被测试其体内生长促进能力,其中大多数分离物显著增加了种子发芽潜力和活力指数。芽孢杆菌属菌株 MBL_B13 的活力指数比不使用细菌接种物的对照高出 26.8%。与对照植物相比,所有接种剂都发现增加了黄麻幼苗的干重,而最显著增加鲜重的是腐生葡萄球菌属菌株 MBL_B9。葡萄球菌巴氏亚种 MBL_B3 表现出多种体外生长促进活性,并在体内盆栽试验中表现出显著的生长促进作用。这些具有促进植物生长能力的细菌菌株具有作为生物接种剂的潜力。