Plant growth promoting bacteria induce anti-quorum-sensing substances in chickpea legume seedling bioassay

Anamika Saral; Saptami Kanekar; Kirtee Kumar Koul; Sameer Suresh Bhagyawant

doi:10.1007/s12298-021-01034-x

Plant growth promoting bacteria induce anti-quorum-sensing substances in chickpea legume seedling bioassay

Physiol Mol Biol Plants. 2021 Jul;27(7):1577-1595. doi: 10.1007/s12298-021-01034-x. Epub 2021 Jul 17.

Authors

Anamika Saral¹, Saptami Kanekar², Kirtee Kumar Koul¹, Sameer Suresh Bhagyawant¹

Affiliations

¹ School of Studies in Biotechnology, Jiwaji University, Gwalior, 474011 India.
² Yenepoya Research Centre, Yenepoya University, Deralakatte, Mangalore, India.

Abstract

Microorganisms and their hosts communicate through an array of signals. Many physiological processes regulated in quorum sensing (QS) are dependent on auto-inducers, like N-acyl-homoserine lactones (AHLs) as in numerous groups of both gram-positive and gram-negative bacteria. In vitro grown seven-day old chickpea seedlings treated with plant growth promoting bacteria (PGPRs) were used to screen the AHL mimicking and for phytochemical substances like phytohormones and secondary metabolites such as phenolics and flavonoids. Potential anti-quorum sensing (anti-QS) activity surrounding the roots on semi-solid agar lawn of Chromobacterium violaceum (ATCC12742) was observed. Crude protein (4.46-8.30 μg/mL) and methanolic extracts (100 μg/mL) of seedling gave moderate anti-QS activity against CV12742 anti QS bioassay, respectively. Crude protein and methanolic extract of Bacillus amyloliquefaciens (34.00 ± 2.23; 34.00 ± 4.33 mm) and B. subtilis A (27.00 ± 2.10; 3.29 ± 2.16 mm) treated samples showed higher zone of inhibition due to anti-QS activity. Phytohormone analysis using LC-MS for zeatin, auxin and methyl jasmonate (MeJA) indicated that phytohormones were significantly upregulated by 1909.80 ng/g FW, 669.67 ng/g FW and 244.55 ng/g FW, respectively in Pseudomonas brassicacearum treated seedlings compared to control. UHPLC of PGPR treated seedlings showed overly expressed gallic acid, protocatechuic acid, catechin, p-hydroxybenzoic acid, caffeic acid, catechol, vanillin, and ferulic acid in B. amyloliquefaciens treated seedlings compared to others. Enrichment analysis identified significant pathways related to metabolism, biosynthesis of secondary metabolites. The present study indicates that chickpea neutralizes an extensive range of functional responses to AHLs that may play important role in legume host-microbe interactions.

Supplementary information: The online version contains supplementary material available at 10.1007/s12298-021-01034-x.

Keywords: Legume; PGPRs; Phenols; Phytohormone; Quorum sensing; UHPLC.