Combining partial host resistance with bacterial biocontrol agents improves outcomes for tomatoes infected with Ralstonia pseudosolanacearum. (September 2020)

• Record Type: Journal Article
• Authors: Subedi, Nagendra; Taylor, Christopher G.; Paul, Pierce A.; Miller, Sally A.
• Is Part Of: Crop protection. Volume 135(2020)
• Publication Date: 2020-09
• Subjects: Bacterial wilt -- Biological control -- Biocontrol efficacy -- Host resistance -- Disease management -- Integrated pest management -- Ralstonia solanacearum species complex -- Bacteria -- Solanaceous crops; Plants, Protection of -- Periodicals; 632.05
• DOI: 10.1016/j.cropro.2019.03.024
• Languages: English
• ISSNs: 0261-2194

Abstract

Abstract: We selected six strains with in vitro antagonism against 15 South Asian strains of Ralstonia pseudosolanacearum from among 54 previously characterized Pseudomonas and other bacterial biocontrol strains and evaluated the value of integration of these biocontrol agents with partial host resistance of tomato in management of bacterial wilt. Biocontrol strains were almost four times more effective in suppressing bacterial wilt in IRAT L3, a partially resistant tomato line, than in L390, a highly susceptible line. Pseudomonas brassicacearum 93D8 and Wood 1R, and P. fluorescens Clinto 1 were the most effective strains with biocontrol efficacy of 68, 47 and 56% respectively, in IRAT L3. Bacterial wilt incidence was suppressed in IRAT L3 in four of four experiments by P. brassicacearum 93D8, and in three of four experiments by P. protegens Clinto 1 and P. brassicacearum Wood 1R. However, in L390, biocontrol efficacy of P . brassicacearum 93D8 and Wood 1R, and P. fluorescens Clinto 1 was 7, 15 and 12%, respectively. There was no correlation between in vitro antagonism of the biocontrol strains against R. pseudosolanacearum and in vivo biocontrol efficacy. These results highlight the value of integration of biocontrol agents with host resistance in management of bacterial wilt. Highlights: Three Pseudomonas strains effectively suppressed bacterial wilt in tomato seedlings. Biocontrol efficacy was 4 times higher in a partially resistant vs. susceptible line. Host resistance genotype is an important component of biocontrol efficacy. A mixture of six biocontrol strains was less effective than the three best strains. 5In vitro antagonism and in vivo biocontrol efficacy were not correlated.