ANTISENSE REPRESSION OF THE MITOCHONDRIAL NADH-BINDING SUBUNIT OF COMPLEX-I IN TRANSGENIC POTATO PLANTS AFFECTS MALE-FERTILITY

Mitochondrial respiratory chain complex I is a large multi-subunit enz yme composed of both organellar and nuclear encoded proteins. To inves tigate the role of the nuclear encoded components, expression of the g ene for the 55 kDa NADH-binding subunit of complex I was disturbed by antisense repression in transgenic potato plants. The antisense constr uct driven by the CaMV 35S promoter decreases the steady-state mRNA le vels of transcripts for the 55 kDa subunit to 33% of the wild type lev els. Quantities of the 55 kDa protein in mitochondrial protein extract s are lowered to about 50% in these plants. Transgenic plants show nor mal vegetative growth and tuber formation, but pollen maturation is fo und to be disturbed. The reduced male fertility of the transgenic 55 k Da antisense plants may be caused by an insufficient mitochondrial res piratory chain, impaired by the decreased expression of the NADH-bindi ng component of mitochondrial complex I. (C) 1997 Elsevier Science Ire land Ltd.