RICE SCIENCE ›› 2013, Vol. 20 ›› Issue (5): 356-362.DOI: 10.1016/S1672-6308(13)60143-2

• Research Paper • Previous Articles     Next Articles

Rhizosphere Bacteria for Biocontrol of Bacterial Blight and Growth Promotion of Rice

  1. 1Department of Biotechnology, School of Bioengineering, SRM University, Kattankulathur 603203, India; 2Department of Botany, The American College, Madurai 625002, India; 3Centre for Advanced Studies in Botany, University of Madras, Chennai 600025, India
  • Online:2013-09-28 Published:2013-07-30
  • Contact: Palaniyandi VELUSAMY

Abstract:

Several bacterial strains were isolated from different rhizospheres. Among these, strain PDY7 exhibited strong antibacterial activity against the rice bacterial blight (BB) pathogen Xanthomonas oryzae pv. oryzae (Xoo) by the laboratory dual plate assays. The antibacterial property of the strain PDY7 was further investigated for the production of 2,4-diacetylphloroglucinol (DAPG), which amplified a characteristic of 629-bp DNA fragment by PCR-based screening method using phlD primers. The application of phlD positive strains was carefully evaluated for disease control and growth promotion of rice plants under field conditions. The selected strain PDY7 suppressed the rice BB by 58.83% and 51.88% under glass house and field conditions, respectively. In addition, the strain PDY7 showed significant two-fold increase in root length (18.08 cm), shoot length (29.81 cm), and grain yield (96.07 g). Strain PDY7 promoted the growth of rice plants by production of indole-3-acetic acid (IAA), which was determined by high performance liquid chromatography (HPLC) analysis. Our findings suggest that PDY7 belongs to the P. fluorescens group and can serve as potential biocontrol of BB as well as biofertilizer agent for growth promotion of rice.

Key words: Pseudomonas fluorescens, bacterial blight, biocontrol, antibacterial activity, plant growth-promoting rhizobacterium