Characterisation of Phytophthora capsici, Causal Agent of Phytophthora Foot Rot Disease of Piper nigrum L. in Sarawak, Malaysia

Phytophthora capsici causes Phytophthora foot rot disease
\non Piper nigrum. The pathogen lacks comprehensive study
\nin Sarawak, Malaysia. In this study, P. capsici was isolated
\nand characterised morphologically and molecularly from ten
\nfarms across three divisions in Sarawak. The pathogenicity
\nof the isolates was confirmed, and distinct colony growth
\npatterns, sporangia morphologies, and radial growth rates
\nwere observed across different media. Torulose hyphae
\nstructures were consistently observed, and compatible mating types were present. Fifty-two isolates retrieved from this
\nstudy were genotyped using five Inter Simple Sequence
\nRepeats and three Random Amplified Microsatellites primers. The UPGMA tree showed a close relationship between
\npopulations. A higher diversity within populations (73%)
\nthan among populations (27%) was observed. This study
\nprovides the first baseline data on the diversity of P. capsici in Sarawak, offering insights for managing the disease’s impact on pepper cultivation and the potential risk of increasing genetic diversity.