Home

Proceedings of the International Academy of Ecology and Environmental Sciences, 2026, 16(1): 1-17
[XML] [EndNote] [RefManager] [BibTex] [ Full PDF (481K)] [Comment/Review Article]

Article

Polyketide Synthase (PKS)-containing foliar endophytes from a traditional rice variety exhibit antagonism against Xanthomonas oryzae pv. oryzae

Jerick A. Viz, Jobriell C. Baluyot, Princess Ashley S. Tomas, Roland M. Hipol
1DOST - Philippine Science High School - Ilocos Region Campus 2728, the Philippines
2Department of Biology, University of the Philippines Baguio, Baguio City 2600, the Philippines
3Institute of Biology, College of Science, University of the Philippines Diliman, Quezon City 1101, Philippines

Received 18 August 2025;Accepted 25 September 2025;Published online 25 November 2025;Published 1 March 2026
IAEES

Abstract
Rice (Oryza sativa L.), a staple diet for the majority of Asians and considered one of the most crucial food crops, often suffer from diseases like Bacterial Leaf Blight (BLB), caused by Xanthomonas oryzae pv. oryzae. Endophytic fungi harbor secondary metabolites, including polyketides, which exhibit potent medicinal properties and, importantly, possess agricultural potential. In this study, we investigated the capability of ethyl acetate extracts derived from foliar endophytic fungi present in Diket red rice to produce bioactive antibacterial compounds. The extracts were tested for their in vitro antimicrobial activity against X. oryzae pv. oryzae, and the presence of polyketide synthase (PKS) genes was also examined. Among the tested isolates, namely Aspergillus spelaeus, Penicillium steckii, Penicillium chrysogenum, and Cladosporium oxysporum, the latter exhibited the most statistically (p>0.05) significant reduction in optical density (OD 600) of X. oryzae pv. oryzae broth cultures compared to positive control (Chloramphenicol), indicating possible antimicrobial activity. Out of the 16 fungal isolates, 15 were found to have the PKS gene, which may account for their antagonistic potential. These findings highlight A. spelaeus, P. steckii, P. chrysogenum, and C. oxysporum as promising candidates for the isolation of bioactive compounds aimed at controlling BLB in the future.

Keywords endophytic fungi;Diket red rice;polyketide;Xanthomonas oryzae p.v. oryzae.


International Academy of Ecology and Environmental Sciences. E-mail: office@iaees.org
Copyright © 2009-2025 International Academy of Ecology and Environmental Sciences. All rights reserved.
Web administrator: office@iaees.org, website@iaees.org; Last modified: 2025/11/14


Translate page to: