Location: Crops Pathology and Genetics Research2012 Annual Report
1. Improving drought tolerance in potted plants. Plant hormone abscisic acid (ABA) plays important roles in the plant stress tolerance pathway against drought. Plants constitutively expressing a key gene in the ABA biosynthesis pathway (NCED) exhibit dramatically enhanced drought tolerance, but show a variety of defects including poor germination, growth and development. We have generated transgenic petunia plants in which NCED is over-expressed under the control of a specific stress-inducible promoter. The plants develop normally under non-stress conditions. The transgenic plants survived and recovered after re-watering when the plants are exposed to low water availability under extreme drought conditions (two weeks without water). This approach overcomes most of the defects associated with constitutive ABA production and provides excellent means for improving drought tolerance.
2. Application of thidiazuron (TDZ) reduced plant height. A common problem in the production of ornamental potted plants is undesirably tall growth, so inhibitors of gibberellic acid (GA) biosynthesis including A-rest (ancymidol), B-nine (daminozide), Bonzi (paclobutrazol), Cycocel (chlormequat chloride), and Sumagic (uniconazole), are commonly used to control plant height. We studied the effects of TDZ applications on the growth and development of potted miniature roses. Plants treated with foliar sprays of TDZ (up to 200µM) exhibited a considerable reduction in plant height compared to the controls (0 µM). TDZ-treated plants tended to have shorter internodes and thicker stems. Our results indicate significant potential for TDZ as an alternative way to control plant height.
De Freitas, S.T., Jiang, C., Mitcham, E.J. 2011. Mechanisms involved in calcium deficiency development in tomato fruit in response to gibberellins. Journal of Plant Growth Regulation. DOI 10.1007/s00344-011-9233-9.
Reid, M.S., Jiang, C. 2012. Postharvest: Cut flowers and potted plants. Review Article. In "Ornamental Geophytes: From Basic Science to Sustainable Production" by CRC Press, Eds. Rina Kamenetsky, Hiroshi Okubo.
Singh, A., Liang, Y., Kumar, P., Reid, M., Jiang, C. 2012. Co-silencing the mirabilis antiviral protein permits virus-induced gene silencing in Mirabilis jalapa. Journal of Horticultural Science and Biotechnology. 87:334-340.