|You, Jiaqi - Huazhong Agricultural University|
|Zhang, J - Huazhong Agricultural University|
|Wu, M - Huazhong Agricultural University|
|Yang, Long - Huazhong Agricultural University|
|Li, Guoqing - Huazhong Agricultural University|
Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/15/2016
Publication Date: 6/16/2016
Citation: You, J., Zhang, J., Wu, M., Yang, L., Chen, W., Li, G. 2016. Multiple criteria-based screening of Trichoderma isolates for biological control of Botrytis cinerea on tomato. Biological Control. 101:31-38.
Interpretive Summary: Plant diseases constitute a major constraint in limiting productivity of crops including legumes and vegetables. Fungicide applications have been routinely used in managing plant diseases in order to maintain crop yield. However, fungicides are expensive and may not be available in developing countries, in addition to posing environmental hazards. Biological control, especially using locally developed biocontrol agents, is an economical alternative in many developing countries. Identifying effective biocontrol agents from local microflora is a tedious process. This research was aimed at developing a set of criteria of efficiently screening fungal species in Trichoderma for biological control applications. It was found that a set of three criteria would be a predictor of effectiveness in biological control. These criteria are invasive growth on plant pathogen colony at different temperatures, production of antifungal substances, and promotion of plant growth. Four isolates of Trichoderma spp. selected based on these criteria significantly reduced disease caused by Botrytis cinerea, suggesting these criteria are effective in selecting potential biocontrol agents.
Technical Abstract: Seventy-two isolates of Trichoderma were obtained from Hubei Province of China and identified to species based on the ITS-rDNA sequences. The isolates were initially tested for invasive growth on the colonies of Botrytis cinerea in the dual cultures with B. cinerea on potato dextrose agar at 20°C. The resulting 28 isolates were further screened for biocontrol potential using three criteria - invasive growth over B. cinerea at 15°C, antifungal activity and promotion of tomato seed germination. Performance of the Trichoderma isolates in the three criteria screening was scored and the total final score was used to select isolates with the highest biocontrol potential. Four isolates (T. harzianum: T-21 and T-68; T. koningiopsis: T-35 and T-51) were selected and evaluated for growth-promotion/resistance-induction effects on tomato seedlings and sporulation-suppression effect on B. cinerea. All the four isolates significantly (P < 0.05) promoted tomato growth possibly through producing gibberellins and indole-3-acetic acid, and induced systemic resistance against B. cinerea possibly through inducing defense-response in colonization of tomato roots/basal stems. Isolates T-21, T-51 and T-68 suppressed B. cinerea sporulation on tomato leaf discs by 62.8, 66.1 and 63.7%, respectively, compared to the control treatment. This study suggests that the multiple criteria-based procedure is rational for screening Trichoderma isolates against B. cinerea, and T. koningiopsisT-51 is a promising BCA and biofertilizer of tomato.