ISHS Acta Horticulturae 490: I International Symposium on Banana in the Subtropics
PHENYLPHENALENONE-TYPE PHYTOALEXINS AND PHYTOANTICIPINS FROM SUSCEPTIBLE AND RESISTANT CULTIVARS OF MUSA SPECIES. ITS POTENCIAL FOR ENGINEERING RESISTANCE TO FUNGI AND NEMATODES INTO BANANA |
| Author: | Javier G. Luis |
| Keywords: | Musa species, phenylphenalenones, disease resistance |
| Abstract:
From a study at the molecular level of the plant-pathogen interaction in the system constituted by Musa species and the pathogenic micro-organisms Micosphaerella fijensis, Fusarium oxysporum f. sp. cubense (fungi) and nematodes, we found that several susceptible banana cultivars produce de novo, either as defensive response to infection or when elicited with kanamycine, a new type of phytoalexins, which have not been described until now. The structure of these substances was established from its spectroscopic data, X-diffraction analysis and chemical correlation. Total chemical synthesis confirmed these structures and supplied material enough for biological assays. Cultured somatic embryos of Musa acuminata also produced, after eight weeks, the same compounds, and the isolation and characterisation of several biosynthetic intermediates led us to postulate a biosynthetic pathway for this new-type phytoalexins. More recently we have also found that several resistant Musa cultivars produce in much larger quantities and like phytoanticipins (constitutive natural antibiotics), the same family of compounds, suggesting that this type of phytoalexins play an important role for resistance to fungal diseases. These results may open a new way to engineer resistance into banana plants. | |
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