Potential for Biocontrol of Monosporascus Root Rot/vine Decline Under Greenhouse Conditions using Hypovirulent Isolates of Monosporascus cannonballus
Academic Article
Overview
Identity
Additional Document Info
Other
View All
Overview
abstract
Monosporascus root rot/vine decline (MRR/VD) causes root necrosis and severe stunting of muskmelon and watermelon plants in several countries around the world. MRR/VD is caused by the soilborne ascomycete fungus, Monosporascus cannonballus. Currently, there are few options available for control of MRR/VD. This research describes experiments to test the possibility of using naturally occurring M. cannonballus isolates containing double-stranded RNA (dsRNA) for the biological control of MRR/VD. These isolates often develop a degenerate phenotype characterized by slow growth and reduced ascospore production. In addition, these degenerate isolates are hypovirulent on muskmelon. Plants co-inoculated with a hypovirulent, dsRNA+ isolate (Tx93-449+) and a virulent, dsRNA- isolate (Az90-33-) at an inoculum ratio of 10: 1 (hypovirulent: Virulent) were indistinguishable from the uninoculated plants in greenhouse pathogenicity trials. In vitro infection assays using fluorescence microscopy on aniline-stained muskmelon roots suggested that although the hypovirulent dsRNA+ isolate Tx93-449+ penetrated and partially colonized roots of the seedlings, it was not as efficient in colonizing the roots as the virulent, dsRNA- isolate Az90-33-. While more extensive experiments are needed, these data suggest that hypovirulent dsRNA+ isolates of M. cannonballus have potential for development as biological control agents to reduce disease pressure associated with MRR/VD.
