Effect of two isolates ofTrichoderma harzianumon the activity of hydrolytic enzymes produced byBotrytis cinerea

Abstract

Two isolates ofTrichoderma harzianum(T39 a biocontrol agent, and NCIM 1185) were tested for their capacity to reduce the level of hydrolytic enzymes produced byBotrytis cinereabothin vitroandin vivo,and to inhibit infection caused byB. cinereaconidia. The hydrolytic enzymes studied were cutin esterase, polygalacturonases (PG), pectin methyl esterase (PME), pectate lyase (PL) and carboxymethyl cellulase (CMCase). On the surface of bean (Phaseolus vulgaris) leaves, isolate T39 inhibited germination ofB. cinereaconidia and subsequent disease development significantly better than isolate NCIM1185. The levels of the various hydrolytic enzymes were reduced whenB. cinereawas grown either with aT. harzianumisolate in liquid culture or on the surface of bean leaves. T39 reduced enzyme levels by about 64, 80, 25, 77, 42 and 23% for cutin esterase, exoPG, endoPG, PME, PL and CMCase, respectively. NCIM1185 caused 57, 60, 5, 87 and 11% reduction in the production of cutin esterase, exoPG, endoPG, PME, PL and CMCase, respectively. However, NCIM1185 enhanced the production of PL when it was grown withB. cinereain liquid culture medium. On the surface of bean leaves, T39 was the better inhibitory agent. The only exception was CMCase, the presence of which was not inhibited by either isolate. Cutin esterase, exo and endoPG, PME and PL ofB. cinereaon bean leaves were reduced in the presence of T39 by ca 20, 95, 100-50, 100 and 95%, respectively. The importance of reduced enzyme activity ofB. cinereain the biocontrol activity ofT. harzianumis discussed.