Molecular Characterization of Trichoderma Strains and Its Biocontrol Efficacy Against Fusarium Moniliforme

Abstract

Trichoderma was described for the first time in 1794 by Persoon. Trichoderma can be found at any place where organic matter is available. The green coloured Trichoderma can be found easily everywhere in all type of soil and as well as wood decaying fungi. Trichoderma species cannot be characterized morphologically due to their resemblance of many characters. To study the diversity of Trichoderma twenty strains were isolated out of forty five soil samples. These isolates were identified morphologically and latterly by the mean of molecular marker tool. There are several molecular methods to characterize fungi species, including isozymes analysis, Restriction Fragment Length Polymorph isms (RFLPs), Random Amplified Polymorphic DNA (RAPD) and DNA sequencing. Sequence analysis of the ITS region is one the famous method among these molecular characterization methods. Therefore, in the present investigation ITS based molecular characterization was performed for the identification of the native strains of the Trichoderma strains. The DNA sequencing of the 5.8S-ITS region was carried out and comparing the sequences was done by TrichOKEY and NCBI. The all the isolates were easily identified except two isolates i.e. SVPP-Si 8 and SVPP-Si 19 were not able to identify which were further analysed by 5.8s gene study at NCBI and was identified as T. harzianum and the second one i.e. SVPP-Si 19 was identified as T. lixii. TrichOKEY identify make group of clade of the all species of Trichoderma which were Lixii-Catoptron for Trichoderma harzianum (eight strains) and Trichoderma atroviride (one strain), Section Longibrachiatum (two strain) for Trichoderma longibrachiatum, Rufa Clade for Trichoderma asperellum (seven strain). Then the sequences were submitted to the NCBI gene bank and the accession numbers were obtained of all the twenty native strains. In the phylogenetic study of aligned sequences by the method Neighbour Joining and UPGMA; the biggest group was found to be the Trichoderma harzianum with including eight strains and Trichoderma asperellum having seven strains in the group with the out group selected from other species and fungus. Thus it revealed with the present study that there are various symbiotic and antagonistic type of microbial strains are present in the soil in which Trichoderma species has gain more popularity than the others. In the genus Trichoderma there are various species having their own properties in which some are good in plant growth promotion and some are very good as antagonist. For the evaluation of biocontrol activity of these isolates these strains were tested aga.inst Fusarium moniliforme causing Bakanae or foot rot disease in rice. In dual culture experiment SVPP-Si 06 and 08 found to be the best in inhibiting the growth of the .Fusarium ·moniliforme. In the experiment of volatile compounds the highest inhibition was observed in isolate SVPP-Si 2 (76.82). In the non-volatile compounds among the different isolates SVPP-Si 18 was very effective and increase 26.14o/o over the control. The highest shoot length of rice plants was observed in SVP Si I 0 that was up to 44.27 % over the controL Root length of rice plants revealed that highest in SVP Si 06 (19.51 %). The flag leaf length of rice plants shows that highest leaf length was observed in isolates SVP Si 17 (39.34 %). In all the isolates SVPP-Si 6 (39.34 %) was found to be highest in increasing the fresh weight and SVPP-Si 03 (35.00 %) was found to be highest in increasing (i.e. 0.94 g) the dry weight of the pI ant.