Molecular insights into the oil palm (Elaeis guineensis) defense response to Ganoderma boninense infection

Abstract

Sustainable oil palm cultivation in the major producing countries, Indonesia and Malaysia is significantly threatened by the fungal pathogen Ganoderma boninense that causes the devastating basal stem rot (BSR). The incidence of the disease has worsened with replanting in previously established plantations resulting in much younger trees being affected. This paper aims to provide a comprehensive review on the response of this important commodity crop to Ganodema boninense at the different stages of infection. It covers the early biotrophic phase when the pathogen established host colonization and the necrotrophic phase when the host succumbed to the disease. It highlights key genes involved in multiple plant defense signaling pathways during oil palm (Elaeis guineensis) infection by Ganoderma boninense, such as nitric oxide associated 1 (EgNOA1), pathogenesis-related protein (EgPR-1), and NADPH oxidase (EgRBOH). It also reviews the roles of transcription factors such as JUNGBRUNNEN 1 (EgJUB1) and Ethylene Responsive Factor 113 (EgERF113) in coordinating defense responses in the biotrophic and necrotrophic phases, respectively, and protein-protein interaction (PPI) involve in regulating oil palm response to the pathogen. Knowledge of molecular interaction of this host plant and the fungal pathogen and the defense mechanisms is essential for developing effective and sustainable strategies for management and treatment of BSR, such as development of an effective disease mitigation strategies and cultivation of disease-resistant oil palm varieties. The review highlights areas which require further research particularly on transcription factors and PPI, to fully elucidate the complex molecular interaction of oil palm and Ganoderma boninense.