Submitted to: Plant Cell Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/1/2011
Publication Date: 9/15/2011
Citation: Qin, H., Gu, Q., Zhang, J., Sun, L., Kuppu, S., Zhang, Y., Burow, M., Payton, P.R., Blumwald, E., Zhang, H. 2011. Regulated Expression of an Isopentenyltransferase Gene (IPT) in Peanut Significantly Improves Drought Tolerance and Increases Yield Under Field Conditions.. Plant Cell Physiology. vol52(11)1904-1914. Interpretive Summary: Drought and heat are major environmental factors that limit agricultural productivity. Decreased availability of arable land for agricultural production, increased water demand for urban use, and declining aquifer levels are the primary constraints placed on food and fiber production now and in the foreseeable future. These issues are compounded by climate change predicitions of increased temperature and rainfall variability in the major agricultural regions of the world, particularly the semi-arid southwestern U.S. The major task facing the scientific community is providing food and clothing to the increasing global population, and doing so on marginal lands using fewer imputs. To meet these needs, innovative strategies must be developed to increase both drought- and heat-tolerance for crops. The objective of this study was to test whether regulated over-expression of isopentenyltransferase (IPT), a key gene in cytokinin biosynthesis, conferred enhanced abiotic stress tolerance in peanut. Our results here show that IPT-expressing plants produce more biomass under reduced irrigation in both glasshouse and field conditions, as well as slightly increased pod yield under field conditions. We propose that the increase in productivity is due to a maintenance of photosynthesetic activity in the trangenic plants compared to the non-expressor and wild-type plants. While these data are preliminary, it is hypothesized that regulated expression of IPT could be one method to significantly improve crop performance under water-limited production schemes.
Technical Abstract: Isopentenyltransferase (IPT) is a critical enzyme in the cytokinin biosynthetic pathway. The expression of IPT under the control of a maturation- and stress-induced promoter was shown to delay stress-induced plant senescence that resulted in an enhanced drought tolerance in both monocot and dicot plants. This report extends the earlier findings in tobacco and rice to peanut (Arachis hypogaea L.) an important oil crop and protein source. Regulated expression of IPT in peanut significantly improved drought tolerance in both laboratory and field conditions. Transgenic peanut plants maintained higher photosynthetic rates, higher stomatal conductance and higher transpiration that wild-type control plants under reduced irrigation conditions. More importantly, transgenic peanut plants produced significantly higher yields than wild-type control plants in the field, indicating a great potential for the development of crops with improved performance and yield in water limited areas of the world.