P-507 - Spatio-Temporal Genetic Diversity and Pathogenicity of Ralstonia solanacearum Affecting Economically Important Crops in the Philippines

Monday, August 4, 2025

4:30 PM - 5:15 PM HST

Location: Exhibit Hall 3

Author(s)

OB

Oliver D. Balanban

University Researcher I
Institute of Plant Breeding, University of the Philippines Los Banos
Los Banos, Laguna, Philippines
BC

Benjamine William P. Cordez

MS Graduate fellow
Institute of Plant Breeding, University of the Philippines Los Banos
Los Banos, Laguna, Philippines
JM

Jay-vee Mendoza

University Research Associate II
Institute of Plant Breeding, University of the Philippines Los Banos
Los Banos, Laguna, Philippines
RT

Rizalina M. Tiongco

Laboratory Technician
Institute of Plant Breeding, University of the Philippines Los Banos
Los Banos, Laguna, Philippines

Presenting Author(s)

FD

Fe Mangaban Dela Cueva (she/her/hers)

Scientist
Institute of Plant Breeding, University of the Philippines Los Banos
Los Baños, Laguna, Philippines

Abstract Text: Bacterial wilt (BW) is a devastating disease that limits global vegetable production. Caused by the soil-borne bacterium Ralstonia solanacearum, this pathogen is highly diverse with four confirmed phylotypes. Breeding for BW-resistant varieties remains to be one of the most sustainable approaches to BW management worldwide. With the complexity of R. solanacearum, understanding its genetic and phenotypic diversity is crucial for a successful breeding program. In the Philippines, the Institute of Plant Breeding, University of the Philippines Los Baños, is mandated to develop disease-resistant crop varieties. Here, the local strains of R. solanacearum isolated from various hosts across different regions in the Philippines (1979-2021) were studied as part of the pre-breeding experiments. For pathogenic diversity, seedlings were drench-inoculated and wilting symptoms were assessed over several days. Disease severity and incubation period were recorded, and the differential aggressiveness was analyzed using SRplot. Genetic diversity was assessed through phylogenetic and haplotype analysis of egl and mutS sequences. Results revealed that the pathogenicity of R. solanacearum generally remained unchanged despite long term storage. Pathogenicity is host-specific wherein banana isolates are clustered with Phylotype II reference strains, while the rest of the isolates clustered with Phylotype I strains. The findings highlight the importance of understanding the diversity and pathogenicity of R. solanacearum for sustainable BW management.