Approaches to and successes in developing transgenically enhanced mycoherbicides

Abstract

Inundative mycoherbicides have not been successful in weed control in row crops, probably due to evolutionary barriers, and adding virulence factors was considered essential. Exogenous addition of the products of various geneswas used to ascertain synergy as a prelude to adding them transgenically. Transgenically over-expressing single "soft" genes (host lytic enzymes such as pectinase, cellulase and expansins, or natural hormones such as IAA), or "hard" genes encoding toxins such as NEP1 and CP1, has enhanced virulence, but not enough. Gene stacking to obtain synergies among the various genes is considered a top priority, both to achieve sufficient virulence and to delay the evolution of weed resistance to the fungal pathogens. © 2007 Springer.