Endophytic Pseudomonas fluorescens Endo2 and Endo35 induce resistance in black gram (Vigna mungo L. Hepper) to the pathogen Macrophomina phaseolina

Muthusamy Karthikeyan*, Ramanujam Bhaskaran, Krishnan Radhika, Subramanian Mathiyazhagan, Velusamy Jayakumar, Rajendran Sandosskumar, Rethinasamy Velazhahan

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

The effect of endophytic Pseudomonas fluorescens isolates Endo2 and Endo35 on induced systemic disease protection against dry root rot 1of black gram (Vigna mungo L. Hepper) caused by Macrophomina phaseolina was investigated under glasshouse conditions.1 When the bacterized black gram plants were inoculated with dry root rot pathogen, the activities of peroxidase (PO), polyphenol oxidase (PPO), phenylalanine ammonia-lyase (PAL) were stimulated in addition to accumulation of phenolics and lignin. Activity of phenylalanine ammonia-lyase (PAL) reached the maximum 24 h after pathogen challenge inoculation, whereas the activities of PO and PPO reached the maximum at 72 h and 48 h, respectively. Isoform analysis revealed that a unique PPO3 isozyme was induced in bacterized black gram tissues inoculated with the pathogen. Phenolics were found to accumulate in bacterized black gram tissues challenged with M. phaseolina one day after pathogen challenge. The accumulation of phenolics reached maximum at the third day after pathogen inoculation. Similar observation was found in the lignin content of black gram plants. In untreated control plants, the accumulation of defence enzymes and chemicals started at the first day and drastically decreased 3 days after pathogen inoculation. These results suggest that induction of defense enzymes involved in phenylpropanoid pathway and accumulation of phenolics and PR-proteins might have contributed to restricting invasion of Macrophomina phaseolina in black gram roots.

Original languageEnglish
Pages (from-to)135-143
Number of pages9
JournalJournal of Plant Interactions
Volume1
Issue number3
DOIs
Publication statusPublished - Sep 1 2005

Keywords

  • Black gram
  • Endophytic bacteria
  • Induced systemic resistance
  • Macrophomina phaseolina
  • Pseudomonas fluorescens

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Plant Science

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