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Selection of Mycosphaerella fijiensis-resistant cell lines from micro-cross sections of banana and plantain

Okole, B.N., Schulz, F.A.
Plant cell reports 1997 v.16 no.5 pp. 339-343
Musa, Mycosphaerella fijiensis, plant pathogenic fungi, mycotoxins, pathogenicity, disease resistance, plant breeding, cell lines, cultivars, genetic variation, in vitro culture, shoots, buds, culture media, micropropagation, explants, culture filtrates
An in vitro selection system using micro-cross sections of banana and plantain cultivars belonging to AAA and A.B. genomic groups were used to produce plants resistant against the Black Sigatoka disease. The fungus resistant plantlets were obtained in a double selection system. This involved in a first step the use of a fungal crude filtrate and in the second step the purified host-specific toxin 2,4,8-trihydroxytetralone extracted from the fungus Mycosphaerella fijiensis (M. fijiensis), the causal agent of Black Sigatoka disease. Resistant plantlets obtained from the double selection system were inoculated with conidia of M. fijiensis in a growth chamber to reproduce Black Sigatoka symptoms. Compared to non-treated control plantlets, which were highly susceptible to the fungus, 10.7-19.3% toxin-resistant plantlets which arose from tissues that went through the double selection system were resistant against M. fijiensis. This technique of using micro-cross sections for selection on fungal toxins seems to be amenable to different Musa genotypes for the production of fungus-resistant plants.