CHANGES IN PATTERNS OF PROTEIN-SYNTHESIS DURING HAUSTORIAL DEVELOPMENT OF STRIGA-HERMONTHICA (DEL) BENTH SEEDLINGS

This study focuses upon the developmental transition of the parasitic plant Striga hermonthica from its free-living state (germinated seedling) to its parasitic state after development of an infection organ: the haustorium, A new method has been developed that allows the production of gram quantities of germinated and haustorially-induced Striga seedlings, thereby facilitating biochemical and molecular analysis of haustorial induction. Water-soluble proteins have been extracted from germinated seeds (stage A) and seedlings treated with 2,6-dimethoxy-p-benzoquinone (2,6-DMBQ) to induce haustorium (stage B), Samples were analysed by two-dimensional polyacrylamide gel electrophoresis and quantitative as well as qualitative differences could be observed. In particular a group of four highly abundant acidic proteins (molecular weight 39 kDa, pl 5.1, 5.3, 5.3, 5.6) and three other proteins (molecular weight 12 kDa, pl 6.9; 17 kDa, pl 4.4; 17 kDa, pl 4.45) were seen in stage A while at least four proteins (molecular weight 21.5 kDa, pl 6.4; 21.5 kDa, pl 6.3; 31 kDa, pl 5.1; 34 kDa, pl 6.2) were present in greater abundance in stage B. In order to compare water-soluble protein with newly synthesized protein patterns, mRNAs from the two stages of development were isolated and cell-free translation products analysed by 2-D PAGE, Two-D gels of cell-free translation products showed the appearance of six proteins in stage B (molecular weight ranging from 10 to 35 kDa) and the presence of three acidic proteins in stage A with one protein (molecular weight 40 kDa) very similar in size to the triplet of proteins in the water-soluble protein 2-D gels.