CBN-V Video Archives - S2-09
A Possible Pole for the dad1 Gene During Post Harvest Physiological Deterioration (PPD) in Cassava

Huang, J. C.C.J.M. Raemakers, M.M. Schreuder E. Jacobsen and R.G.F Visser

Laboratory of Plant Breeding, Department of Plant Sciences, The Graduate School of Experimental Plant Science (EPS), Wageningen University (WU), P. O. BOX 386, 6700 AJ Wageningen, The Netherlands
jiang.huang@pv.dpw.wau.nl

        The isolation of a TDF (Transcript Derived Fragment), named TDFa12, is described, which exhibits a differentially expression pattern during the first 72 hours of PPD in cassava. TDFa12 showed most sequence similarity with some of the representative dad1 (defender against apoptotic death) homologues from other species such as Arabidopsis, apple, rice, human, mouse and C. elegans. Southern hybridisation results suggested that dad1 has a low copy number in the cassava genome. Transformants were prepared using particle bombardment of cassava FEC (friable embryogenic callus) lines with DNA carrying the putative cassava dad1 homologue in an antisense orientation under the control of the CaMV 35s promoter. Two strategies were taken for the production of transgenic plants: one based on luciferase screening only and one on kanamycin plus luciferase selection. It was proven that cassava FEC lines could be bombarded with a mixture of two different isolated plasmids and that co-transformation occurred at a high frequency for the first time. The transgenic nature of the plants was confirmed by Southern blotting using the luciferase gene as a probe. The transgenic plant lines showed new phenotypic changes; i.e. being early senescence in leaves, which might be attributed to the expression of the introduced dad1 gene. The possible reasons for this alternative morphology in the transgenic plant is given and discussed.

2007© Donald Danforth Plant Science Center All rights reserved.