Modulation of Programmed Cell Death for Disease Development/Stress Tolerance in Plants

We have generated transgenic plants that express plant (eg BAG) as well as animal genes (eg CED-9) that negatively regulate apoptosis.  These genes also have the potential to generate effective disease resistance/stress tolerance in economically important crop plants.  For example, the vast majority of bananas grown today have not undergone improvement through conventional breeding.  The major reason for this is that most cultivars are essentially sterile.  An alternate strategy is to improve current cultivars through genetic modification. We have found that A. tumefaciens exposure induces a programmed cell death in banana cell suspensions.  More than 90% of embryogenic banana cells died after exposure to A. tumefaciens and cell death was accompanied by a subset of features associated with apoptosis in mammalian cells, including DNA laddering, fragmentation, and formation of apoptotic-like bodies. Importantly, these cellular responses were inhibited in cells expressing anti-apoptosis genes. In addition, these plants were drought tolerant and exhibited resistance to the major fungal pathogen of banana, Panama wilt disease. In analogous studies, we will discuss sugarcane improvement efforts via transformation primarily for cold tolerance in an effort to expand the potential growing region of elite sugarcane varieties.  Field studies are underway for both crop plants. Time permitting, we will also discuss bioinformatic efforts to identify plant genes predicted to function in an apoptotic-like manner, serving as candidate genes for crop improvement.