Targeted transcriptional and proteomic studies explicate specific roles of Bacillus subtilis iturin A, fengycin, and surfactin on elicitation of defensive systems in mandarin fruit during stress

PLoS One. 2019 May 23;14(5):e0217202. doi: 10.1371/journal.pone.0217202. eCollection 2019.

Abstract

Application of Bacillus cyclic lipopeptides (CLPs); fengycin, iturin A and surfactin has shown a great potential in controlling the spread of green mold pathogen invasion (Penicillium digitatum) in wounded mandarin fruit during postharvest period. The limited defensive protein profiles followed specific expression of pivotal genes relating to plant hormone mediating signaling pathways of the CLPs' action on stimulating host plant resistance have been exhibited. The present study aimed to elucidate the specific effect of individual CLP obtained from Bacillus subtilis ABS-S14 as elicitor role on activation of plant defensive system at transcriptional and proteomic levels with and without P. digitatum co-application in mandarin fruit. Fengycin and iturin A elevated the gene expression of PAL, ACS1, ACO, CHI, and GLU while significantly stimulating plant POD transcription was only detected in the treatments of surfactin both with and without following P. digitatum. An increase of LOX and PR1 gene transcripts was determined in the treatments of individual CLP with fungal pathogen co-application. Fengycin activated production of unique defensive proteins such as protein involved in ubiquinone biosynthetic process in treated flavedo without P. digitatum infection. Proteins involved in the auxin modulating pathway were present in the iturin A and surfactin treatments. CLP-protein binding assay following proteome analysis reveals that iturin A attached to 12-oxophytodienoate reductase 2 involved in the oxylipin biosynthetic process required for jasmonic acid production which is implicated in induced systemic resistance (ISR). This study suggests specific elicitor action of individual CLP, particularly iturin A showed the most powerful in stimulating the ISR system in response to stresses in postharvest mandarins.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antifungal Agents / pharmacology
  • Bacillus subtilis / drug effects
  • Bacillus subtilis / physiology*
  • Citrus / drug effects
  • Citrus / genetics
  • Citrus / immunology*
  • Citrus / metabolism
  • Fruit / drug effects
  • Fruit / immunology
  • Fruit / metabolism
  • Gene Expression Regulation, Plant / drug effects*
  • Lipopeptides / pharmacology*
  • Peptides, Cyclic / pharmacology*
  • Plant Diseases / immunology
  • Plant Diseases / microbiology
  • Plant Proteins / genetics
  • Plant Proteins / metabolism
  • Proteome / analysis
  • Proteome / drug effects*
  • Stress, Physiological
  • Transcriptome / drug effects*

Substances

  • Antifungal Agents
  • Lipopeptides
  • Peptides, Cyclic
  • Plant Proteins
  • Proteome
  • fengycin
  • iturin A

Grants and funding

This work was financially supported by the National Royal Research Council of Thailand (Grant no. SCI600214S) (http://en.nrct.go.th/en/home.aspx), Paiboon Tunsagool is grateful for a Thailand Research Fund, Royal Golden Jubilee Ph.D. student scholarship (PHD/0172’2557) (https://www.trf.or.th/) (https://rgj.trf.or.th/main/en/), and to the University Academic Excellence Strengthening Program in Biochemistry at Prince of Songkla University (PSU) (https://www.psu.ac.th/th/) (http://www.sci.psu.ac.th/New56/TH/index.asp), and the PSU Graduate Fund (https://grad.psu.ac.th/en/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.