Bacterial Root Endophytes: Characterization of Their Competence and Plant Growth Promotion in Soybean ( Glycine max (L.) Merr.) under Drought Stress

Anamika Dubey, Diksha Saiyam, Ashwani Kumar, Abeer Hashem, Elsayed Fathi Abd_Allah and Mohammed Latif Khan
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Anamika Dubey: Metagenomics and Secretomics Research Laboratory, Department of Botany, Dr. Harisingh Gour University (A Central University), Sagar 470003, MP, India
Diksha Saiyam: Department of Biotechnology, Dr. Harisingh Gour University (A Central University), Sagar 470003, MP, India
Ashwani Kumar: Metagenomics and Secretomics Research Laboratory, Department of Botany, Dr. Harisingh Gour University (A Central University), Sagar 470003, MP, India
Abeer Hashem: Botany and Microbiology Department, College of Science, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia
Elsayed Fathi Abd_Allah: Plant Production Department, College of Food and Agricultural Sciences, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia
Mohammed Latif Khan: Metagenomics and Secretomics Research Laboratory, Department of Botany, Dr. Harisingh Gour University (A Central University), Sagar 470003, MP, India

IJERPH, 2021, vol. 18, issue 3, 1-19

Abstract: 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 Fusarium oxysporum (ITCC 2389), Macrophomina phaseolina (ITCC 1800), and Alternaria alternata (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 Bacillus cereus (GenBank accession No. MN079048), Pseudomonas otitidis (MW301101), and Pseudomonas 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 ( p ≤ 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.

Keywords: drought stress; plant growth promotion; endophytic bacteria; biocontrol activity; agriculture productivity (search for similar items in EconPapers)
JEL-codes: I I1 I3 Q Q5 (search for similar items in EconPapers)
Date: 2021
References: View complete reference list from CitEc
Citations: View citations in EconPapers (2)

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