Specific response of partially purified cell wall-bound ATPases to fungal suppressor

It was found that NTPases were bound to cell walls of pea and cowpea. The suppressor in pycnospore germination fluid of a pea pathogen, Mycosphaerella pinodes, inhibited the ATPase activity in the fraction, which was solubilized from pea cell wall with 0.5% Triton X-100, in a cowpea cell wall even at the concentration of 1 μg ml^-1, Inhibition by the suppressor of pea cell wall-bound ATP-ase was a unixed type of competitive and noncompetitive. Triton X-100 PAGE and active staining of ATPase indicated that both Triton X-100 solubilized fractions contained plural molecules that hydrolyze ATP. The M,s of cell wall-bound ATPases seem to be considerably different from those of plasma membranes, and the number of cell wall-bound ATPase molecules were different between pea and cowpea. The electroeluted fractions corresponding to the bands of active-stained ATPases were also able to hyases also showed the species-specific response to the suppressor. These results may confirm our previous concept that putative receptors for the suppressor might tightly bind to cell wall-bound ATPase or that the ATPase might be the receptor itself.