Molecular and biochemical approaches to understanding oil palm - Ganoderma interactions. - (:unkn) unknown (Kuala Lumpur : MPOB,, 2007)
Interest in the changes in gene expression patterns of Ganoderma boninense infected oil palm has increased since basal stem rot caused by this fungus is the most serious disease of oil palm in Malaysia. Extensive studies to identify global changes in gene expression during pathogen-host interaction have enhanced discovery of genes regulating the plant defence response to pathogen attack. The identification of defense-related genes governing the interaction of G. boninense and oil palm would provide insights into development of diagnostic tools and identification of resistant varieties. Quantitative methods for global and simultaneous analysis of expression profile, such as Suppression Subtractive Hybridisation and Annealing Control Primer would also be powerful in identifying the genes that are specifically or predominantly expressed in infected or healthy palms. Using both approaches, cDNA libraries representing 1098 differentially expressed genes (DEG) in response to G. boninense infection were generated. Sequence data indicated that of the 1,098 clones obtained, 933 (85%) clones showed sequence similarity to proteins registered in the public databases, 110 (10%) clones showed similarities to putative protein sequences and 55 (5%) resulted as unknown proteins. A number of 16 clones harboring genes encoding for defense mechanisms against fungal and insect pathogens in plants has been identified. All 16 genes are pathogenesis-related (PR)-genes and defense-related genes according to their direct or indirect roles in plant defense against pathogens. Reverse Northern analysis of all the genes demonstrated that 7 were differentially expressed with respect to infected palms. Northern analysis of the 7 genes showed that only 5 were differentially expressed. Further analysis via RT-PCR confirmed these 5 genes to be differentially expressed G. boninense infected oil palms. A complementary approach was used to identify changes in protein abundance during interaction of oil palm with G. boninense. The soluble protein fractions from different infected and healthy susceptible oil palm seedlings at different weeks following artificial inoculation were analysed by two-dimensional gel electrophoresis. Mass spectrometry was used in efforts to identify differences in proteins and metabolites between uninfected and Ganoderma-infected tissues. Identification of phenolic compounds by high performance liquid chromatography and analysis of total soluble phenolic compounds were also carried out. The results obtained in the current study indicate that phenolic compounds are involved in oil palm resistance against Ganoderma. These findings will enhance the understanding of molecular mechanism in response to infection and will contribute towards ultimately developing a diagnostic tool for early detection of Ganoderma infection and Ganoderma tolerance.
Incluye referencias bibliográficas.
Interest in the changes in gene expression patterns of Ganoderma boninense infected oil palm has increased since basal stem rot caused by this fungus is the most serious disease of oil palm in Malaysia. Extensive studies to identify global changes in gene expression during pathogen-host interaction have enhanced discovery of genes regulating the plant defence response to pathogen attack. The identification of defense-related genes governing the interaction of G. boninense and oil palm would provide insights into development of diagnostic tools and identification of resistant varieties. Quantitative methods for global and simultaneous analysis of expression profile, such as Suppression Subtractive Hybridisation and Annealing Control Primer would also be powerful in identifying the genes that are specifically or predominantly expressed in infected or healthy palms. Using both approaches, cDNA libraries representing 1098 differentially expressed genes (DEG) in response to G. boninense infection were generated. Sequence data indicated that of the 1,098 clones obtained, 933 (85%) clones showed sequence similarity to proteins registered in the public databases, 110 (10%) clones showed similarities to putative protein sequences and 55 (5%) resulted as unknown proteins. A number of 16 clones harboring genes encoding for defense mechanisms against fungal and insect pathogens in plants has been identified. All 16 genes are pathogenesis-related (PR)-genes and defense-related genes according to their direct or indirect roles in plant defense against pathogens. Reverse Northern analysis of all the genes demonstrated that 7 were differentially expressed with respect to infected palms. Northern analysis of the 7 genes showed that only 5 were differentially expressed. Further analysis via RT-PCR confirmed these 5 genes to be differentially expressed G. boninense infected oil palms. A complementary approach was used to identify changes in protein abundance during interaction of oil palm with G. boninense. The soluble protein fractions from different infected and healthy susceptible oil palm seedlings at different weeks following artificial inoculation were analysed by two-dimensional gel electrophoresis. Mass spectrometry was used in efforts to identify differences in proteins and metabolites between uninfected and Ganoderma-infected tissues. Identification of phenolic compounds by high performance liquid chromatography and analysis of total soluble phenolic compounds were also carried out. The results obtained in the current study indicate that phenolic compounds are involved in oil palm resistance against Ganoderma. These findings will enhance the understanding of molecular mechanism in response to infection and will contribute towards ultimately developing a diagnostic tool for early detection of Ganoderma infection and Ganoderma tolerance.
Keywords: Ganoderma.; Plagas.; Palma de aceite