Genetic diversity and antagonistic properties of Trichoderma strains from the crop rhizospheres in southern Rajasthan, India

Authors: JAMBHULKAR, PRASHANT - Central Agricultural University; SINGH, BHUMICA - Central Agricultural University; RAJA, MANOKARAN - Central Agricultural University; Ismaiel, Ed - Ed; Lakshman, Dilip; TOMAR, MAHARISHI - Icar - Indian Institute Of Horticultural Research; SHARMA, PRATIBHA - University College - India

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/27/2024
Publication Date: 4/14/2024
Citation: Jambhulkar, P., Singh, B., Raja, ., Ismaiel, A.A., Lakshman, D.K., Tomar, M., Sharma, P. 2024. Genetic diversity and antagonistic properties of Trichoderma strains from the crop rhizospheres in southern Rajasthan, India. Scientific Reports. https://doi.org/10.1038/s41598-024-58302-5.
DOI: https://doi.org/10.1038/s41598-024-58302-5

Interpretive Summary: Many species of Trichoderma are commonly used for environment-friendly and sustainable management of plant diseases. In addition to direct parasitism of pathogens, Trichoderma species are also known to induce disease resistance and improve soil and rhizospheric health and plant growth promotion. A crop rhizosphere-based survey of Trichoderma species was conducted in 7 districts of Rajasthan state of India, covering 16 cultivated crops and orchards. Based on molecular methods and morphological characteristics, 74 isolates were identified as Trichoderma, of which 60 isolates were classified into eight species: Trichoderma brevicompactum (16), T. erinaceum (15), T. asperellum (12), T. harzianum (13), T. atroviride (01), T. ghanense (01), T. longibrachiatum (01), and T. hamatum (01). The morphology and cultural characteristics of the separate individual species were observed, described, and illustrated. Information gathered on crop selectivity, genetic diversity, and geographical adaptation of Trichoderma isolates will be beneficial for developing efficient biocontrol strategies. That information will also serve as a useful reference to plant pathologists, mycologists, extension workers for developing alternative disease management practices.

Technical Abstract: There are fewer studies on Trichoderma diversity in agricultural fields. The rhizosphere of 16 crops was analyzed for Trichoderma species in 7 districts of Rajasthan state of India. Based on DNA sequence of translation elongation factor 1a (tef-1a), and morphological characteristics, 60 isolates were identified as 11 species: Trichoderma brevicompactum, species in Harzianum clade identified as T. afroharzianum, T. inhamatum, T. lentiforme, and T. camerunense, T. asperellum, T. asperelloides, T. erinaceum, T. atroviride, T. ghanense, and T. longibrachiatum. T. brevicompactum is the most commonly occurring strain followed by T. afroharzianum. No new species were described in this study. T. lentiforme, showed its first occurrence outside the South American continent. The morphological and cultural characteristics of the major species were observed, described, and illustrated in detail. The isolates were tested for their antagonistic effect against three soilborne plant pathogens fungi: Sclerotium rolfsii, Rhizoctonia solani, and Fusarium verticillioides in plate culture assays. One of the most potent strains was T. afroharzianum BThr29 having a maximum in vitro inhibition of S. rolfsii (76.6%), R. solani (84.8%), and F. verticillioides (85.7%). Such information on crop selectivity, antagonistic properties, and geographic distribution of Trichoderma species will be beneficial for developing efficient Trichoderma-based biocontrol agents.