Bacillus subtilis CBR05 induces Vitamin B6 biosynthesis in tomato through the de novo pathway in contributing disease resistance against Xanthomonas campestris pv. vesicatoria

Murugesan Chandrasekaran,Manivannan Paramasivan,Se-Chul Chun

doi:10.1038/s41598-019-41888-6

Murugesan Chandrasekaran, Manivannan Paramasivan + Show 1 more

Open Access

https://doi.org/10.1038/s41598-019-41888-6

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Journal: Scientific Reports	Publication Date: Apr 24, 2019
Citations: 18	License type: open-access

Affiliation: Sejong University, Bharathidasan University

Abstract

Expression profiling for genes involved in Vitamin B6 (VitB6) biosynthesis was undertaken to delineate the involvement of de novo and salvage pathway induced by Bacillus subtilis CBR05 against, Xanthomonas campestris pv. vesicatoria in tomato. Pyridoxine biosynthesis (PDX) genes such as PDX1.2 and PDX1.3, were found to be overexpressed significantly at 72 hpi in B. subtilis and pyridoxine inoculated plants. Most significant upregulation was observed in the transcript profile of PDX1.3, which showed more than 12- fold increase in expression. Unfortunately, salt sensitive overlay4 (SOS4) profiling showed irregular expression which corroborates that SOS4 role in VitB6 biosynthesis needs further studies for deciphering a clear notion about their role in tomato. Antioxidant enzymes i.e., superoxide dismutase, catalase, polyphenol oxidase, and peroxidase activities clearly demonstrate escalation till 48 hpi and gets reduced in 72 hpi. Pot trials also confirm that B. subtilis compared to pyridoxine supplementation alone show plant disease resistance and elongated roots. The present study confirms that B. subtilis, as a versatile agent in eliciting induced systemic resistance regulated by de novo pathway as a model for plant defense against X. campestris pv. vesicatoria substantiated by VitB6 biosynthesis. Nevertheless, the study is preliminary and needs further evidence for affirming this phenomenon.

Highlights

The cofactor Vitamin (VitB6) is a combination of six water-soluble vital vitamers with a common pyridine ring composed of variations in 4′ moieties possessing alcohol pyridoxine (PN), amine pyridoxamine (PM), aldehyde pyridoxal (PL) and 5′ phosphorylated forms (PNP, PMP, PLP)[1]
The studies lucidly show that the hypersensitive response (HR) in tobacco leaves infected with Pseudomonas syringae pv. phaseolicola was affected with excess Vitamin B6 (VitB6) content, rather P. syringae pv. tabaci infection resulted in augmented disease severity[18]
PDX1.2, PDX1.3, PDX2 genes overexpression confirms the authentic involvement of the de novo pathway of VitB6 biosynthesis in tomato upon Xanthomonas campestris pv. vesicatoria (XCV) infection

Summary

Introduction

The cofactor Vitamin (VitB6) is a combination of six water-soluble vital vitamers with a common pyridine ring composed of variations in 4′ moieties possessing alcohol pyridoxine (PN), amine pyridoxamine (PM), aldehyde pyridoxal (PL) and 5′ phosphorylated forms (PNP, PMP, PLP)[1]. The salvage pathway predominantly is responsible for the conversion of vitamer forms through specific enzyme modificiation[6,7] It converts, PN, PM, and PL to active co-factor PLP by the concerted activities of a vitB6 kinase (salt overlay sensitive 4 (SOS4)) through phosphorylation while biosynthesis of PLP from PN and PM requires the activity of a www.nature.com/scientificreports/. Studies showed that abiotic stress response comprises of pyridoxal kinase and pyridoxal reductase enzymes which play a significant role mediated by salvage pathway[8,9,10,11]. Previous studies clearly depict salicylic acid (SA), methyl jasmonate (JA), and ethylene (ET) act as the chemical counterparts in inducing plant defense response abating oxidative stress through overexpression of PDX transcript in Nicotiana tabacum and Hevea brasiliensis[18,19]. It is clearly evident that Bacillus sp. is an essential regulator of ISR

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