Rhizobia Contribute to Salinity Tolerance in Common Beans (Phaseolus vulgaris L.)
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Date
2022-11
Authors
Wekesa, Clabe
Asudi, George O.
Okoth, Patrick
Reichelt, Michael
Muoma, John O.
Furch, Alexandra C. U.
Oelmüller, Ralf
Journal Title
Journal ISSN
Volume Title
Publisher
MDPI
Abstract
Rhizobia are soil bacteria that induce nodule formation on leguminous plants. In the
nodules, they reduce dinitrogen to ammonium that can be utilized by plants. Besides nitrogen fixation,
rhizobia have other symbiotic functions in plants including phosphorus and iron mobilization and
protection of the plants against various abiotic stresses including salinity. Worldwide, about 20%
of cultivable and 33% of irrigation land is saline, and it is estimated that around 50% of the arable
land will be saline by 2050. Salinity inhibits plant growth and development, results in senescence,
and ultimately plant death. The purpose of this study was to investigate how rhizobia, isolated from
Kenyan soils, relieve common beans from salinity stress. The yield loss of common bean plants, which
were either not inoculated or inoculated with the commercial R. tropici rhizobia CIAT899 was reduced
by 73% when the plants were exposed to 300 mM NaCl, while only 60% yield loss was observed after
inoculation with a novel indigenous isolate from Kenyan soil, named S3. Expression profiles showed
that genes involved in the transport of mineral ions (such as K+, Ca2+, Fe3+, PO4
3, and NO3
) to the
host plant, and for the synthesis and transport of osmotolerance molecules (soluble carbohydrates,
amino acids, and nucleotides) are highly expressed in S3 bacteroids during salt stress than in the
controls. Furthermore, genes for the synthesis and transport of glutathione and
-aminobutyric
acid were upregulated in salt-stressed and S3-inocculated common bean plants. We conclude that
microbial osmolytes, mineral ions, and antioxidant molecules from rhizobia enhance salt tolerance in
common beans.
Description
article
Keywords
rhizobia, RNA_Seq, transcriptomics, common beans, salinity tolerance, GABA, osmotolerance, meta-RNA-Seq
Citation
Wekesa, C.; Asudi, G.O.; Okoth, P.; Reichelt, M.; Muoma, J.O.; Furch, A.C.U.; Oelmüller, R. Rhizobia Contribute to Salinity Tolerance in Common Beans (Phaseolus vulgaris L.). Cells 2022, 11, 3628. https://doi.org/ 10.3390/cells11223628