Characterization of novel <i>Trichoderma</i> spp. isolates as a search for effective biocontrollers of fungal diseases of economically important crops in Argentina

Abstract

Monoconidial cultures of 33 isolates of <i>Trichoderma</i> from Buenos Aires Province, Argentina were characterized on the basis of twenty eight morphological, physiological and biochemical features. All of them were screened for proteinase, endochitinase and β-1,3 glucanase activity. Universally primed PCR (UP-PCR) and inter-simple sequence repeat (ISSR) techniques were used to examine the genetic variability among isolates, which resulted in 127 bands for the total number of isolates. These results were subjected to numerical analysis revealing 20 haplotypes grouped in five clusters. The ability of <i>Trichoderma</i> isolates to antogonize soil-borne fungal plant pathogens using a dual culture assay was done against five fungal species: <i>Alternaria</i> sp., <i>Bipolaris sorokiniana</i>, <i>Fusarium graminearum</i>, <i>F. solani</i>, and <i>Pyricularia oryzae</i>. The highest inhibition values (85% RI) were obtained against <i>B. sorokiniana</i> and <i>P. oryzae</i>. Three isolates of <i>T. harzianum</i> named as FCCT2, FCCT3 and FCCT9 were capable of causing a high growth inhibition on four of the fungal species assayed, which was in agreement with their higher extracellular hydrolytic activity. Our results suggest that these isolates have the potential to be effective agents for biocontrol of cereal and tomato fungal pathogens.