Identity and biocontrol efficiency of Trichoderma spp. isolated from different soils and ecosystems in Algeria

Forty-six strains of Trichoderma spp. have been isolated from soils in different locations and ecosystems of Algeria. They were identified at species level by analysis of their Internal Transcribed Spacers regions 1 and 2 (ITS1 and ITS2) of rDNA and a partial sequence of the Translation Elongation Factor 1-alpha (TEF 1-α) gene. The 46 Trichoderma spp. were assigned to Trichoderma atroviride (12 strains), T. gamsii (10), T. orientale (1) and 23 to T. harzianum species complex (T. harzianum, T. afroharzianum, T. atrobrunneum and T. guizhouense). In the present study we highlight that T. gamsii, T. orientale, T. atrobrunneum and T. guizhouense are being reported for the first time in Algeria. Trichoderma spp. isolates growth was evaluated at temperatures ranging from 10 to 40 °C on PDA medium. The optimum growth was recorded at 25 °C and 30 °C, and only T. orientale was able to grow at 40 °C. The in vitro test revealed the potential antagonist of Trichoderma spp. isolates against four pathogenic species associated with strategic crops in Algeria, Fusarium culmorum, Botrytis cinerea, Alternaria solani and Rhizoctonia solani. In direct confrontation, the growth rate inhibition was ranked between 37.22% and 80.95% while in indirect confrontation was between 00% and 88.89%. The biocontrol assay carried out on wheat plant showed that T. atroviride (Ta.09), T. orientale (To.15), T. afroharzianum (T af. 17 and T af. 37) and T. gamsii (T g. 39) performed well against F. culmorum the crown rot and head blight pathogen of wheat in Algeria. This finding is based on the significant decrease in disease severity compared to the control (> 82%). Data recorded, have also shown that T. atroviride Ta.09 recorded the highest percentage of disease reduction (97.28%).s