ISHS Acta Horticulturae 334: I International Pineapple Symposium
DEVELOPMENT OF RESISTANCE TO INFECTION BY FUSARIUM MONILIFORME VAR. SUBGLUTINANS IN WOUNDS OF PINEAPPLE PLANTLETS |
| Authors: | A.P. de Matos, X. Mourichon |
| Keywords: | lignification, wound periderm, wound healing, fusariose, Ananas comosus |
| Abstract:
The pineapple disease fusariose, caused by Fusarium moniliforme var. subglutinans, is the major factor limiting pineapple production in Brazil. Wounds generated by lateral bud development seem to constitute sites of entrance of the pathogen thus resulting in infected asexual propagative parts. In order to determine the time course of wound resistance development, Smooth Cayenne (susceptible) and Queen (highly susceptible) pineapple plantlets were wounded and inoculated either immediately or after growth at 26 to 28 C and 80% relative humidity for 1, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20 and 22 days. Disease incidence and severity decreased as the time interval between wounding and inoculation increased. Smooth Cayenne had the greatest response. Disease development occurred on all plantlets inoculated immediately after wounding. No infection was observed in Smooth Cayenne plantlets that had healed for 8 or for Queen plantlets that had healed for 18 or more days before inoculation. Histochemical tests of tissues near wounds were positive for lignin, suberin, phenolic compounds and callose. A well defined wound periderm was observed 6 and 14 days postwounding in Smooth Cayenne and Queen, respectively. These results indicate the involvement of a healing process on the development of resistance to F. moniliforme var. subglutinans in wounds of pineapple plantlets. The decrease in disease susceptibility as postwounding time increases varies according to the pineapple cultivar. | |
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