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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Molecular Plant Pathology Laboratory » Research » Publications at this Location » Publication #417389

Research Project: Omics-Based Approach to Detection, Identification, and Systematics of Plant Pathogenic Phytoplasmas and Spiroplasmas

Location: Molecular Plant Pathology Laboratory

Title: Trichoderma: Harzianum complex clade species distribution in soils of Central and South America

Author
item Ismaiel, Ed - Ed
item JAMBHULKAR, PRASHANT - Central Agricultural University
item SINHA, PARIMAL - Indian Agricultural Research Institute
item Lakshman, Dilip

Submitted to: The Journal of Fungi
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/21/2024
Publication Date: 11/23/2024
Citation: Ismaiel, A.A., Jambhulkar, P.P., Sinha, P., Lakshman, D.K. 2024. Trichoderma: Harzianum complex clade species distribution in soils of Central and South America. The Journal of Fungi. 10/813. https://doi.org/10.3390/jof10120813.
DOI: https://doi.org/10.3390/jof10120813

Interpretive Summary: Environmentally sustainable disease management and increased crop productivity mandate the use of fewer inputs of chemical pesticides and fertilizers. Selected species of Trichoderma act as biofertilizers and biocontrol agents in plants. Nearly 60% of all biological fungicides have Trichoderma species as the active ingredient, with T. harzianum as the most common species. However, the name T. harzianum has often been incorrectly used due to the recent division of this complex clade into more than 95 cryptic species. We studied strains previously identified as T. harzianum in five survey studies from soil in South and Central America and found that species of T. afroharzianum, T. lentiforme, T. endophyticum followed by T. azedevio and T. harzianum are the common species. This study will facilitate selecting strains within the complex clade for biocontrol and biofertilizer products in the continent. The information generated would be useful to plant pathologists, extension agents, and farmers.

Technical Abstract: As environmental and health concerns increase due to excessive use of Agrochemicals, the sustainable agriculture trend moves toward using biological agents. Fungal species in the Trichoderma genus have been known to have biological activities of biocontrol and growth promotion. About 60% of all biological fungicides have Trichoderma species as the active ingredient, with T. harzianum as the most common species in these products. However, the name T. harzianum has often been incorrectly used in culture collections, databases, and the scientific literature due to the splitting of the Harzianum Complex Clade (HCC) into more than 95 cryptic species with only one being named T. harzianum. In this study, strains previously identified as T. harzianum in three surveys of Trichoderma species from soil in South and Central America were reanalyzed using multilocus phylogeny based on DNA sequences of tef1a, rpb2, and ITS loci. Based on phylogenetic analysis, the strains were given new names. The number of strains for each species was combined with the corresponding species in two other studies, where species of Trichoderma were correctly identified with the above three loci. Based on the results of the five surveys, T. afroharzianum, T. lentiforme, T. endophyticum followed by T. azedevio and T. harzianum were found to be the dominant species of the HCC in South and Central America. T. harzianum is present in the continent even though previous data showed it is commonly a North American and European species. Furthermore, phylogenetic analyses showed that T. austoindianum clustered with T. azevedoi in one monophyletic clade and some strains of the two species had identical sequences. Therefore, T. ausoindianum was tabulated as T. azevedoi since the latter was described earlier than T. ausoindianum. The analysis also showed that the species T. peberdyi is not part of HCC as reported in the original description. This is the first report of identifying dominant Trichoderma species within the HCC in South and Central American soil based on multiple studies, which will be useful in selecting strains within the complex clade for formulation of biocontrol and biofertilizer products in the continent.