Elicitation of resistance and associated defense responses in Trichoderma hamatum induced protection against pearl millet downy mildew pathogen.
Endophytic Trichoderma hamatum UoM 13 isolated from pearl millet roots was evaluated for its efficiency to suppress downy mildew disease. Under laboratory conditions, T. hamatum seed treatment significantly enhanced pearl millet seed germination and seedling vigor. T. hamatum seed treatment resulted in systemic and durable immunity against pearl millet downy mildew disease under greenhouse and field conditions. T. hamatum treated seedlings responded to downy mildew infection with high lignification and callose deposition. Analysis of defense enzymes showed that T. hamatum treatment significantly enhanced the activities of glucanase, peroxidase, phenylalanine ammonia-lyase, and polyphenol oxidase in comparison to untreated control. RT-PCR analysis revealed differentially expressed transcripts of the defense enzymes and PR-proteins in treated, untreated, and checks, wherein PR-1, PR-5, and cell wall defense HRGPs were significantly over expressed in treated seedlings as against their lower expression in controls. T. hamatum treatment significantly stimulated endogenous salicylic acid (SA) levels and significantly upregulated important SA biosynthesis gene isochorismate synthase. The results indicated that T. hamatum UoM13 treatment induces resistance corresponding to significant over expression of endogenous SA, important defense enzymes, PR-proteins, and HRGPs, suggesting that SA biosynthetic pathway is involved in pearl millet for mounting systemic immunity against downy mildew pathogen.
Department of Studies in Biotechnology, University of Mysore, Manasagangotri, Mysore, 570006, Karnataka, India.
Chandra Nayaka
CN
Siddaiah
Department of Studies in Microbiology, Karnataka State Open University, Mukthagangotri, Mysore, 570006, Karnataka, India.
Niranjan Raj
NR
Satyanarayana
Microbiology Division, DRDO-BU-Centre for Life sciences, Bharathiar University Campus, Coimbatore, 641046, Tamil Nadu, India.
Venkataramana
V
Mudili
Discipline of Biochemistry, National University of Ireland Galway, Galway, Ireland.
Vijai
V
Kumar Gupta
Microbiology Division, DRDO-BU-Centre for Life sciences, Bharathiar University Campus, Coimbatore, 641046, Tamil Nadu, India.
Selvakumar
S
Gurunathan
Frontier Research Center for Post-Genome Science and Technology, Hokkaido University, Sapporo 060-0808, Japan.
Shobith
S
Rangappa
Department of Studies in Biotechnology, University of Mysore, Manasagangotri, Mysore, 570006, Karnataka, India.
Shekar Shetty
SS
Huntrike
International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, 502324, Telangana, India.
Rakesh Kumar
RK
Srivastava
D060467:Disease Resistance; D004798:Enzymes / Q000235:genetics; D020869:Gene Expression Profiling; D018525:Germination; D005936:Glucans / Q000378:metabolism; D008031:Lignin / Q000378:metabolism; D031782:Pennisetum / Q000254:growth & development / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology*; D010935:Plant Diseases / Q000276:immunology*; D060888:Real-Time Polymerase Chain Reaction; D020156:Salicylic Acid / Q000378:metabolism; D036226:Seedlings / Q000254:growth & development / Q000382:microbiology; D012639:Seeds / Q000254:growth & development / Q000382:microbiology; D014242:Trichoderma / Q000254:growth & development*
D004798:Enzymes; D005936:Glucans; D008031:Lignin; C048306:callose; D020156:Salicylic Acid