Profiling secondary metabolites of plant defence mechanisms and oil palm in response to Ganoderma boninense attack

Abstract

Oil palm ecosystems comprise a wide range of fungi, bacteria, insects, nematodes, and viruses that are significantly responsible for reducing crop productivity. One of the most destructive diseases of oil palm caused by Ganoderma boninense, a wood decaying fungi, is basal stem rot (BSR). The BSR occurs due to fungal mycelia invasion, which spreads to the bole of the plant. In addition to spreading by contact with infected roots, BSR also spreads via airborne basidiospores. Cell wall components including lignins are usually broken down by these fungi. The BSR causes the reduction of oil palm fresh fruit bunch (FFB) yield and the collapse of the palms. Plants show varying degrees of protective potential under unfavourable conditions, such as attack by a variety of pathogenic microorganisms and herbivores as well as different abiotic stresses in nature, depending on the ability of the plants to produce secondary metabolites, including phenolics, terpenes, sulphur (S)- and nitrogen (N)-containing compounds. So far, few studies have highlighted the importance of secondary metabolites involved in the response of oil palm to BSR. This review provides an overview of some of the metabolites involved in the defence mechanisms of plants against pathogenic microbes as well as under various abiotic stresses. This study also illustrates the effect of N, phosphorus (P) and potassium (K) fertilizers towards the suppression of pathogenic attacks by increasing the production of secondary metabolites.