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Impact of biotic and abiotic factors on Phytophthora species invasion (Durian Stem Canker)

2
1 Chong Sok Leng, Nik Mohd Izham Mohamed Nor, Siti Nordahliawate Mohamed Sidique
1
*

1 Laboratory for Pest, Disease and Microbial Biotechnology (LAPDiM), Faculty of Fisheries and Food
Science, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia.
2 School of Biological Sciences, Universiti Sains Malaysia, 11800, Penang, Malaysia.

* Corresponding author: dahliasidique@umt.edu.my

Abstract:
Constant opening of more durian orchards with the rise of durian industry in Malaysia is triggered by the
high demands from local consumption and also international exports to high economical countries such as
China, Singapore and Australia. However, little knowledge on plant disease control among the newly arise
durian growers would be expected to face difficulties if not properly managed. Stem canker is a major
durian plant disease caused by oomycete, the Phytophthora pathogen. This pathogen causes Phytophthora
root rot and stem canker starting from its soil-borne inoculum. A quick development and fast spreading of
air-borne spores will invade the upper plant parts causing Phytophthora leaf blight and fruit rot. Thus, stem
canker disease outbreak will cause a disastrous state to durian industry of Malaysia. There is a need of more
understanding in pathogen complexity with other factors (biotic and abiotic). This study will focus on three
objectives; (1) to determine the occurrence of Phytophthora pathogen causing durian stem canker in
Peninsular Malaysia, (2) to confirm the interaction among soil microbial community and environment
conditions in durian orchards and also (3) to obtain the proportion of Phytophthora air-borne spores present
in durian orchards and weather conditions. Field work will be conducted at 15 selected durian orchards
around Peninsular Malaysia (stem canker disease assessments, soil sampling and obtain air-borne spores).
Phytophthora species will be confirmed by applying molecular identification. Other laboratory analysis
such as metagenomic of soil samples, soil properties (pH and texture) and nutrient analysis (ICP-OES) will
also be carried out. Finally, quantitative PCR (qPCR) detection will be performed to determine proportion
of Phytophthora air-borne spores in the air. This study will give insight on relationships between biotic
elements (Phytophthora species and soil microbial community) and abiotic elements (soil properties, soil
nutrients, weather conditions and land topography) causing durian stem canker. Results will contribute on
the decision making for disease control of durian stem canker in Malaysia.

Keywords: Durian, Phytophthora, Stem canker, Air-borne Spores, Disease control