Role of Melanin in Colletotrichum falcatum Pathogenesis Causing Sugarcane Red Rot
Melanin is one of the well-known secondary metabolite produced by fungi and other organisms which has a major role in pathogenicity. Our earlier studies established positive correlation on the production of secondary metabolites such as toxins, enzymes and melanin in relation to pathogen virulence and disease expression. In the present investigation, melanin induction as one of the factor in differentiating pathogen virulence was proved by extraction and quantification. The role of melanin in the pathogenesis of Colletotrichum falcatum has been studied in detail under the influence of melanin inhibitor, tricyclazole. Effect of tricyclazole on C. falcatum pathogenesis revealed that it is inhibitory to conidial germination, appressorium formation and its melanisation at lower concentrations. However, efficacy of tricyclazole was increased with increase in concentration in reducing C. falcatum growth, sporulation and symptom production in leaves and stalks. Finally, the presence of melanin in C. falcatum was confirmed by amplifying three melanin biosynthesis genes, viz. PKS1, SCD1 and THR1 at molecular level. The results confirm that melanin plays one of the important roles in C. falcatum pathogenesis and melanin inhibiting compounds have definite role in disease suppression by external application.
KeywordsRed rot Colletotrichum falcatum Pathogenesis Melanin Inhibitor
The authors are grateful to the Director, ICAR-Sugarcane Breeding Institute, for providing facilities and constant encouragement.
This study was done as part of ICAR-SBI fund.
Compliance with Ethical Standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Kubo, Y., and I. Furusawa. 1991. Melanin biosynthesis: prerequisite for the successful invasion of the plant host by appressoria of Colletotrichum and Pyricularia. In The fungal spore and disease initiation in plants and animals, ed. G.T. Cole, and H.C. Hoch, 205–218. New York: Plenum.CrossRefGoogle Scholar
- Malathi, P., R. Viswanathan, A. Arunkumuran, and G. Ganeshkumar. 2012. Fungal pathogenicity gene expression as a tool to measure defense gene expression during Sugarcane × Colletotrichum falcatum interaction. DHR International Journal of Biomedical and Life Sciences 3 (1): 2278–8301.Google Scholar
- Malathi, P., R. Viswanathan, P. Padmanaban, D. Mohanraj, and A. Ramesh Sundar. 2002. Microbial detoxification of Colletotrichum falcatum toxin. Research communications-Current Science 83: 745–749.Google Scholar
- Pihet, M., P. Vandeputte, G. Tronchin, G. Renier, P. Saulnier, S. Georgeault, R. Mallet, D. Chabasse, F. Symoens, and J.P. Bouchara. 2009. Melanin is an essential component for the integrity of the cell wall of Aspergillus fumigatus conidia. BMC Microbiology 9: 177.CrossRefPubMedPubMedCentralGoogle Scholar
- Srinivasan, K.V., and N.R. Bhat. 1961. Red rot of sugarcane: Criteria for grading resistance. Journal of the Indian Botanical Society 40: 566–577.Google Scholar
- Subhani, M.N., M.A. Chaudhry, A. Khaliq, and F. Muhammad. 2008. Efficacy of various fungicides against sugarcane red rot (Colletotrichum falcatum). International Journal of Agriculture and Biology 10 (6): 725–727.Google Scholar
- Ten, L.N., N.N. Tepanichenko, A.A. Tyschenko, M.M. Faiziev, S.Z. Mukhammedzhanov, and K.A. Aslanov. 1987. Melaninogenesis and toxin production in phytopathogenic fungi. Microbiology 49: 34–41.Google Scholar
- Yamaguchi, I., and Y. Kubo. 1992. Target sites of melanin biosynthesis inhibitors. In Target sites of fungicide action, ed. W. Koller, 101–118. Boca Raton FL: CRC Press.Google Scholar