title: Identification, characterization and phylogenetic analysis of antifungalTrichodermafrom tomato rhizosphere.
abstract: The use ofTrichodermaisolates with efficient antagonistic activity represents a potentially effective and alternative disease management strategy to replace health hazardous chemical control. In this context, twenty isolates were obtained from tomato rhizosphere and evaluated by their antagonistic activity against four fungal pathogens (Fusarium oxysporumf. sp.lycopersici,Alternaria alternata,Colletotrichum gloeosporoidesandRhizoctonia solani). The production of extracellular cell wall degrading enzymes of tested isolates was also measured. All the isolates significantly reduced the mycelial growth of tested pathogens but the amount of growth reduction varied significantly as well. There was a positive correlation between the antagonistic capacity ofTrichodermaisolates towards fungal pathogens and their lytic enzyme production. TheTrichodermaisolates were initially sorted according to morphology and based on the translation elongation factor 1-α gene sequence similarity, the isolates were designated asTrichoderma harzianum,T. koningii,T. asperellum,T. virensandT. viride. PCA analysis explained 31.53, 61.95, 62.22 and 60.25% genetic variation amongTrichodermaisolates based on RAPD, REP-, ERIC- and BOX element analysis, respectively.ERG-1gene, encoding a squalene epoxidase has been used for the first time for diversity analysis of antagonisticTrichodermafrom tomato rhizosphere. Phylogenetic analysis ofERG-1 gene sequences revealed close relatedness ofERG-1sequences with earlier reported sequences ofHypocrea lixii,T. arundinaceumandT. reesei.However,ERG-1 gene also showed heterogeneity among some antagonistic isolates and indicated the possibility of occurrence of squalene epoxidase driven triterpene biosynthesis as an alternative biocontrol mechanism inTrichodermaspecies.
authors.affiliation: ICAR-National Bureau of Agriculturally Important Microorganisms (NBAIM), Mau, Uttar Pradesh 275103 India.
authors.forename: Shalini
authors.initials: S
authors.lastname: Rai
authors.affiliation: ICAR-National Bureau of Agriculturally Important Microorganisms (NBAIM), Mau, Uttar Pradesh 275103 India ; ICAR-Indian Institute of Wheat and Barley Research (IIWBR), Regional Station, Flowerdale, Shimla, 171002 India.
authors.forename: Prem Lal
authors.initials: PL
authors.lastname: Kashyap
authors.affiliation: ICAR-Indian Institute of Wheat and Barley Research (IIWBR), Karnal, Haryana 132001 India.
authors.forename: Sudheer
authors.initials: S
authors.lastname: Kumar
authors.affiliation: ICAR-National Bureau of Agriculturally Important Microorganisms (NBAIM), Mau, Uttar Pradesh 275103 India.
authors.forename: Alok Kumar
authors.initials: AK
authors.lastname: Srivastava
authors.affiliation: Sam Higginbottom Institute of Agriculture, Technology and Sciences (SHIATS), Allahabad, 211007 India.
authors.forename: Pramod W
authors.initials: PW
authors.lastname: Ramteke
keywords: Antagonism; Biocontrol; Diversity; Ergosterol; Tomato; Trichoderma