Chloride transport in the vegetative mycelia of filamentous fungus Trichoderma viride

Abstract

The influx of chlorides into Trichoderma viride vegetative submerged mycelium was measured by means of the radionuclide (36)Cl(-). It was found that the (36)Cl(-) influx was time-dependent (the steady-state was established with t(1/2 )= 25 min at 25 degrees C), pH-dependent (with pH optimum between 4-5.5), temperature-dependent (at about 15 degrees C), and concentration-dependent (K(M)(Cl(-))) = 47.6 +/- 4.2 micromol x l(-1); J(max) = 11.5 +/- 0.7 pmol(Cl(-)) x min(-1). mg(dry mass) (-1)). The (36)Cl(-) influx was inhibited by Br(-) but not F(-), I(-), SO(4)(2-), HPO(3)(2-) and HCO(3)(-). The presence of vanadate (P-type ATPase inhibitor) moderately stimulated the (36)Cl(-) influx but the presence valinomycin (electrogenic K(+) ionophore), salicylate (known to release Ca(2+) from Trichoderma viride internal stores) were without effect on the (36)Cl(-) influx. The results suggest that the (36)Cl(-) influx is mediated by a carrier and that the transport is electroneutral, probably Cl(-)/OH(-) antiport.