Development of a herbicide resistance trait incapable of pollen transmission to weed plants

Weeds can gain herbicide resistance by receiving pollen from crop plants and acquiring resistance genes directly. Such weeds are tremendous problems especially for rice farmers in the southern US states as well as in Asia Latin America and Europe. This weedy rice problem is eroding the efficacy of herbicides resulting in significant gain yield losses. Consequently it is highly desirable to produce crop plants that cannot transmit herbicide resistance through pollen. Such crop plants are not available currently; however the new technology we develop at NAPIGEN will provide a means for their development. We previously have developed technologies for gene editing of plant mitochondrial DNA a goal that had eluded plant scientists for decades. Therefore we can introduce an herbicide resistance gene into the mitochondrial genome. Since mitochondria are maternally inherited the mitochondrial herbicide resistance gene will not be transmitted by outcrossing to weed plants. Unlike nuclear DNA plant cells can have hundreds of copies of mitochondrial DNA. A current challenge is ensuring that engineered mitochondrial DNA is the dominant species in a transformed plant cell. In this project we propose selection methods to increase the proportion of engineered mitochondrial DNA having an herbicide resistance gene. The technology obtained from this project can be used to develop other novel mitochondrial traits in crop plants such as cytoplasmic male sterility for hybrid seed production improved nitrogen use efficiency and enhanced drought tolerance each of which would increase crop yields under normal as well as stressful conditions worsen by climate change.