HISTOCHEMICAL ANALYSES OF MALE REPRODUCTIVE DEVELOPMENT IN GLYPHOSATE-TOLERANT COTTON (GOSSYPIUM HIRSUTUM)

摘要

Plants expressing sufficient amount of Agrobacterium sp. strain CP4 5-enolpyruvylshikimate-3-phosphate synthase (CP4 EPSP synthase) are known to possess tolerance to glyphosate, a potent herbicide that inhibits the activity of endogenous EPSP synthase. While good vegetative tolerance to glyphosate has been shown in many different plant species, some CP4-expressing plants exhibit male sterility after extensive glyphosate applications. This male sterile phenomenon implies that the expression of CP4 protein may be insufficient in male reproductive tissues in these cases. We have generated two different glyphosate-resistant cotton lines. Both lines give excellent vegetative glyphosate tolerance. One of the lines (GTCot 60-1) shows great reproductive success after extensive glyphosate application at late developmental stages. The other line (GTCot 1445), however, exhibits male sterility in some flowers after multiple glyphosate application at late developmental stages. Histochemical analyses were conducted on these two lines to dissect the male reproductive development in response to glyphosate applications at the cellular level. The correlation between glyphosate injury and the expression of CP4 EPSP synthase in the male reproductive tissues of these plants will be discussed.