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Characterization of native Trichoderma spp. from Indian Himalayas and their evaluation against salinity stress

KrishiKosh

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Title Characterization of native Trichoderma spp. from Indian Himalayas and their evaluation against salinity stress
 
Creator Rawat, Laxmi
 
Contributor Singh, Y.
 
Subject characterization, Trichoderma, India, Himalayas, mountain areas, salinity salt stress, biological control
 
Description Thesis-PhD
Trichoderma spp. have been extensively used as a biological agent for the management of a large number of soil borne, seed –borne and foliar plant pathogens by employing various mechanisms. In the present study, 55 native Trichoderma isolates were obtained from soil samples collected from different farming situations of Uttarakhand. Initially all the 55 isolates were screened for their antagonistic potential against three major soil borne plant pathogens viz., R.solani, S. rolfsii and F. oxysporum. High antagonistic activity inhibiting mycelia growth (42.21-90.13%) against all the test pathogens by most of the Trichoderma isolates was observed. As abiotic stresses like temp., pH, drought, salinity etc could be responsible for inconsistent performance of Trichoderma spp. in heterogenous environmental conditions, selected isolates were therefore screened for their tolerance to these stresses under in vitro condition. On the basis of preliminary studies, five isolates of Trichoderma harzianum (Th-13, Th-14, Th-19, Th-33, and Th-50) showing optimum mycelia growth, sporulation and biocontrol efficacy under both natural and saline medium, were selected as salinity tolerant (ST) for further investigations. Ten isolates (Th-1,Th-5,Th-13,Th-14,Th-19,Th-33,Th-45,Th-50 and Th-55) , selected on the basis of their performance in different lab experiment assays, were evaluated under glass house conditions, out of which Th-1 followed by Th-9 and Th-14 performed best regarding different planting value parameters in rice and mustard. Whereas, under field conditions, Th-14 showed maximum plant growth promotion and biocontrol potential against S .rolfsii and F. oxysporum f.sp. ciceri in lentil and chickpea, respectively followed by Th-1. In wheat, maximum plant growth promotion activity was recorded with Th-1 followed by Th-9. As salinity is one of the major constraints limiting plant productivity as well as Trichoderma growth, four subsequent experiments were conducted in wheat, rice and chickpea crops to assess the effects of seed biopriming with selected ST isolates of T. harzianum under different levels of salt stress to reduce the deleterious effects of salinity on growth, physiological and biochemical parameters. In germination test, Th-14, Th-19 and Th-13 were effective in improving germination percentage and reducing RPG during salinity stress. The results indicated that the untreated plants were more sensitive to salt stress. Length and fresh weights of root and shoot, number of leaves, photosynthetic rate, Fv/Fm ratio, Total chlorophyll, SPAD value and MSI reduced in untreated plants in comparison to Trichoderma treated plants at all stress levels. Trichoderma treated plants exhibited reduced RPG and lower accumulation of MDA content as compared to control. However, it was observed that different treatments had non significant effect on LWC. The higher proline content, MSI and lower MDA accumulation might have imparted salt tolerance in Trichoderma treated plants. Agronomical parameters studied in case of rice grown under natural saline-sodic soil indicated that salt stress significantly reduced number of tillers, number of panicles, panicle length and 1000 grain weight. However, per cent decrease was significantly low in Trichoderma treated plants. In chickpea, Th-14 and Th-19 significantly reduced the wilt disease incidence caused by F. oxysporum f.sp. ciceri under salt stress. Simultaneously, the population density of both the isolates far exceeded than of Fusarium under both non-saline and saline soil conditions. However, Th-14 was found more efficient in dropping the F.oxysporum growth in rhizosphere. It is concluded that seed biopriming with different ST Trichoderma isolates reduced the severity of the effects of salinity though amelioration was better in Th-14 for most of the parameters studied under present environmental material and conditions. Gene expression profiling for some key genes potentially involved under stress condition such as SOD,PAL,APX, and PC5S was done trough RT-PCR (reverse transcriptase) and found that expression was directly correlated with previously studied physiological and biochemical parameters .Thus, stress induced changes in gene expression pattern were significantly effected in Th-14 treated seedlings.
 
Date 2016-07-25T14:59:03Z
2016-07-25T14:59:03Z
2011-01
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/69803
 
Language en
 
Format application/pdf
 
Publisher G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)