Es. Mutasa-gottgens et al., Specific polyclonal antibodies for the obligate plant parasite Polymyxa - a targeted recombinant DNA approach, PLANT PATH, 49(2), 2000, pp. 276-287
Highly specific rabbit polyclonal antibodies for the obligate sugar-beet ro
ot parasite, Polymyxa betae, were produced using a novel recombinant DNA ap
proach. Parasite cDNA was selectively isolated from infected roots, express
ed in vitro, and the purified protein used to raise antibodies. This produc
ed clean, precisely targeted antibodies, and allowed for rigorous screening
of candidate genes and their products at the molecular level prior to anim
al immunization. This approach selects for genes whose products are highly
expressed by the parasite in planta, and five such candidate genes from Pol
ymyxa betae were identified and cloned. Polyclonal antiserum developed usin
g the product of one such gene was found to react specifically with P. beta
e in sugar-beet roots and with the closely related Polymyxa graminis in bar
ley roots, and to cross-react with Plasmodiophora brassicae in cabbage root
s, without the need for further purification. No cross-reaction was detecte
d with protein extracts from potato roots infected by the plasmodiophoromyc
ete Spongospora subterranea. In all cases, there was no interaction with pr
oteins from host plants, or from other microorganisms found in association
with uninoculated sugar-beet, barley, cabbage and potato roots.