Ganoderma tornatum

Abstract: Basal stem rot is an aggressive disease in oil palm caused by Ganoderma species. The disease threatens the commercial oil palm plantations of South East Asia, especially in Malaysia. In order to understand the mechanism involved in the early stage of interaction between Ganoderma spp. and its host at systemic level, proteomic analysis of oil palm leaves was conducted on protein samples collected over 72 hours during inoculation with pathogenic Ganoderma boninense and non-pathogenic Ganoderma tornatum. A total of 82 proteins resolved during two-dimensional gel electrophoresis with significant differences in the spot abundance. However, only 24 differentially expressed proteins in response to Ganoderma spp. inoculations were successfully identified by mass spectrophotometry as compared to the non-inoculated control. These proteins are mainly involved in photosynthesis, signalling, stress/defense, energy and metabolism regulation. Changes in relative abundance of these proteins suggest an important role in disease susceptibility. Most proteins showed altered abundance in response to both G. boninense and G. tornatum, while some proteins were only affected by either G. boninense or G. tornatum. The putative role of the identified proteins in oil palm leaves during the interaction with both Ganoderma spp. is discussed.

Abstract: Mating compatibility and restriction analyses of Internal Transcribed Spacer (ITS) regions were performed to determine the relations between Ganoderma boninense, the most common species associated with basal stem rot in oil palm and Ganoderma isolates from infected oil palm, two ornamental palms, sealing wax palm (Cyrtostachys renda) and MacArthur palm (Ptychosperma macarthurii), an isolate from coconut stump (Cocos nucifera), Ganoderma miniatocinctum, Ganoderma zonatum and Ganoderma tornatum. The results showed that G. boninense was compatible with Ganoderma isolates from oil palm, G. miniatocinctum and G. zonatum, Ganoderma isolates from sealing wax palm, MacArthur palm and coconut stump. G. boninense was not compatible with G. tornatum. Therefore, the results suggested that the G. boninense, G. miniatocinctum, G. zonatum, and Ganoderma isolates from oil palm, ornamental palms and coconut stump could represent the same biological species. In performing a restriction analysis of the ITS regions, variations were observed in which five haplotypes were generated from the restriction patterns. An unweighted pair-group method with arithmetic averages (UPGMA) cluster analysis showed that all the Ganoderma isolates were grouped into five primary groups, and the similarity values of the isolates ranged from 97% to 100%. Thus, a restriction analysis of the ITS regions showed that G. boninense and the Ganoderma isolates from other palm hosts were closely related. On the basis of the mating compatibility test and the restriction analysis of the ITS regions performed in this study, a diverse group of Ganoderma species from oil palm and other palm hosts are closely related, except for G. tornatum and Ganoderma isolates from tea and rubber.

Abstract: Basal stem rot disease caused by Ganoderma spp. is still considered a large threat to oil palm production in many countries, especially in Malaysia, which contributes to approximately 45% of the world's palm oil exports. In the last 10 years, studies on the oil palm-Ganoderma interaction have mainly focused on the response of the plant towards the fungus. In this study, a comparative proteomic analysis was conducted to investigate the change in protein expression of two Ganoderma spp., namely Ganoderma boninense, which is known as the most aggressive species and Ganoderma tornatum, previously reported as non-pathogenic. Our results showed that both species colonize and penetrate the oil palm root after only 72 h of inoculation. In addition, proteins were expressed differentially in both species that have either direct or indirect links to virulence and pathogenicity. Other proteins related to fungal growth, metabolism and stress from both species were also discussed in this study.