RT Journal T1 UNRAVELING THE PROTECTIVE POTENTIAL OF SPERMOSPHERE BACTERIA IN MITIGATING RICE BROWN SPOT (Bipolaris oryzae (Breda de Haan) Shoemaker) INFECTION A1 J. Sheela A1 E. G. Ebenezar A1 M. Theradimani A1 S. Ragul A1 M P. Tamilmalar A1 A. Aravinthkumar A1 N. Rajinimala A1 M. Paramasivan A1 M. Arumugampillai JF Journal of Animal and Plant Sciences JO JAPS SN 1018-7081 VO 34 IS 6 SP 1616 OP 1629 YR 2024 FD 2024/12/22 DO DOI https://doi.org/10.36899/JAPS.2024.6.0837 AB

Bipolaris oryzae, fungal pathogen causing rice brown spot disease, exerts a significant economic impact by reducing rice yield and quality. The costs associated with the management of this destructive pathogen, including fungicide applications and other preventive measures, increase the cost of cultivation and pave the way for the economic burden faced by rice farmers and the broader agricultural industry. Taking this into consideration, 32 spermosphere bacteria were isolated from various rice landraces and challenged against the virulent isolate of Bipolaris oryzae (OM977033) under in vitro conditions. Among them, six strains of spermosphere bacteria from different rice seeds exhibited notable inhibitory effects on the tested pathogen. SPKKM 4 isolated from Navara, SPKKM 2 from Mappillaisamba, SPKKM 5 from Navara black, SPKKM 18 from Kavuni, SPKKM 9 from Mallikar and SPKKM 32 from ADT 44 rice seeds exhibited pronounced inhibition of Bipolaris oryzae mycelial growth. Furthermore, seedling vigor assessments revealed the remarkable growth-promoting potential of SPKKM 5, SPKKM 4, and SPKKM 2 among the tested bacterial strains. Molecular characterization confirmed their identities as Bacillus subtilis (OQ073461), Acinetobacter schindleri (OK342196) and Acidovorax spp. (OP522279), respectively. Subsequent pot culture experiments demonstrated that Bacillus subtilis (SPKKM 5) applied at 10 ml kg-1 as seed treatment and foliar spray (0.5%) at flowering and 15 days later, resulted in a remarkable 65.86% reduction in disease incidence compared to the control.

K1 Rice brown spot, Bipolaris oryzae, spermosphere bacteria, rice landraces, Bacillus subtilis PB Pakistan Agricultural Scientists Forum LK https://thejaps.org.pk/AbstractView.aspx?mid=2024-JAPS-1623