Metagenomics and Secretomics Research Laboratory, Department of Botany, Dr. Harisingh Gour University (A Central University), Sagar 470003, MP, India.
Department of Biotechnology, Dr. Harisingh Gour University (A Central University), Sagar 470003, MP, India.
Int J Environ Res Public Health. 2021 Jan 21;18(3):931. doi: 10.3390/ijerph18030931.
Recently, the application of endophytes in the alleviation of different types of stresses has received considerable attention, but their role in drought stress alleviation and growth promotion in soybean is not well-stated. In this study, twenty bacterial endophytes were isolated from soybean root tissues and screened for plant growth-promoting (PGP) traits, biocontrol potential, and drought stress alleviation. Out of them, 80% showed PGP traits, and 20% showed antagonistic activity against (ITCC 2389), (ITCC 1800), and (ITCC 3467), and only three of them showed drought tolerance up to 15% (-0.3 MPa). Results indicated that drought-tolerant PGP endophytic bacteria enhanced soybean seedling growth under drought stress conditions. Morphological, biochemical, and molecular characterization (16S rRNA) revealed that these three bacterial isolates, AKAD A1-1, AKAD A1-2, and AKAD A1-16, closely resemble (GenBank accession No. MN079048), (MW301101), and sp. (MN079074), respectively. We observed that the soybean seedlings were grown in well-watered and drought-stressed soil showed the adverse effect of drought stress on morphological (stem length, root length, plant fresh and dry weight) as well as on biochemical parameters (a decline of photosynthetic pigments, membrane damage, etc.). However, soybean seedlings inoculated with these endophytes have improved the biomass significantly ( ≤ 0.05) under normal as well as in drought stress conditions over control treatments by influencing several biochemical changes. Among these three endophytes, AKAD A1-16 performed better than AKAD A1-2 and AKAD A1-1, which was further validated by the ability to produce the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase in the following order: AKAD A1-16 > AKAD A1-2 > AKAD A1-1. Scanning electron microscopy images also showed a bacterial presence inside the roots of soybean seedlings. These findings supported the application of bacterial root endophytes as a potential tool to mitigate the effect of drought as well as of fungal diseases on the early seedling growth of soybean.
最近，内生生境在缓解不同类型胁迫方面的应用引起了相当大的关注，但它们在缓解大豆干旱胁迫和促进生长方面的作用尚未得到充分阐述。在这项研究中，从大豆根组织中分离出 20 种细菌内生菌，并对其进行了植物促生（PGP）特性、生物防治潜力和缓解干旱胁迫的筛选。其中，80%表现出 PGP 特性，20%表现出对 （ITCC 2389）、 （ITCC 1800）和 （ITCC 3467）的拮抗活性，只有 3 种表现出耐旱性，耐旱能力高达 15%（-0.3 MPa）。结果表明，耐旱型 PGP 内生细菌能在干旱胁迫条件下促进大豆幼苗生长。形态学、生物化学和分子特征（16S rRNA）表明，这三个细菌分离株 AKAD A1-1、AKAD A1-2 和 AKAD A1-16，分别与 （GenBank 登录号 MN079048）、 （MW301101）和 sp.（MN079074）密切相似。我们观察到，在充分浇水和干旱胁迫土壤中生长的大豆幼苗表现出干旱胁迫对形态学（茎长、根长、植株鲜重和干重）和生物化学参数（光合色素下降、膜损伤等）的不利影响。然而，接种这些内生菌的大豆幼苗在正常和干旱胁迫条件下的生物量均有显著提高（≤0.05），优于对照处理，这是通过影响几种生化变化实现的。在这三个内生菌中，AKAD A1-16 的表现优于 AKAD A1-2 和 AKAD A1-1，其产 1-氨基环丙烷-1-羧酸（ACC）脱氨酶的能力依次为：AKAD A1-16＞AKAD A1-2＞AKAD A1-1。扫描电子显微镜图像也显示了细菌存在于大豆幼苗的根部。这些发现支持将细菌根内生菌作为一种潜在的工具来减轻干旱以及真菌病害对大豆幼苗早期生长的影响。
