Metabolomics Analysis on Antifungal Activities Produced by Penicillium oxalicum T3.3 Grown on Different Types of Carbon Sources

Colletotrichum gloeosporioides, known as one of the world’smost plant pathogenic fungi can cause a serious damage to most parts of plants including stems, fruits, roots, leaves, and flowers but are often highly specific to individual tissues (Bailey et al. 1992). This pathogenic fungus attacked an extremely wide range of plants growing in both temperate and tropical environments. In Korea, C. gloeosproriodes had been identified as the cause of anthracnose disease that attack tulip trees as the necrotic lesions became black as the spots expanded on the leaves of that trees (Choi et al. 2012). The first report of anthracnose of Pisonia alba, commonly called lettuce tree was reported in India described the C. gloeosproriodes as the fungus that produced white mycelia, which became dark grey with later formation of numerous salmon pink colored spore masses (Vidyalakshmi and Divya, 2013).

In Malaysia, the first report on the occurrence of anthracnose disease in dragon fruit (Hylocereus spp.) caused by this fungus was reported by Masyahit et al. (2009). The infected stem and fruit had reddish-brown lesions or black spots symptoms where it can expand and merge to cover the whole affected area. At present, the great potential health benefit (Ching and Yusof, 2005), physic-chemical characteristics (Chuah et al. 2008) and nutritional value (Ariffin et al. 2009; Rebecca et al. 2008) of dragon fruit had been a great interest among the researchers, however the exploitation of natural organism as biological control and the potentialities of these microorganisms in production of bioactive metabolites and bio-control agents in controlling the pathogenic fungi has not receive any further investigations yet.

There is no agreement on which media are the optimal for metabolite production. However, according to Mathan et al. (2013), the growth media and incubation conditions have avery great influence on secondary metabolites production. Some of the physical and chemical parameters like pH, temperature, carbon and nitrogen sources playa major role on fungal growth and production of bioactive compounds and antimicrobial agents (Gunasekaran and Poorniammal, 2008; Mathan et al. 2013). The availability and type of carbon and nitrogen source gives effect on polyketide production whereby carbon source such as glucose and sucrose have been found to increase the fungal growth and sporulation along with the high aflatoxin production (Keller et al. 2002).

Metabolomics can be described as a comprehensive quantitative and qualitative analysis of holistic metabolites present in a biological organism, which are the end-products of its gene expression (Van der kooy et al. 2009). There are many tools that can be used to analyze large number metabolites simultaneously such as nuclear magnetic resonance (NMR), gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS) and Fourier transform infrared spectroscopy (FTIR). Some of them rely on chromatographic separation step and others do not require any in which represent a global view of the sample (Ulrich-Merzenich et al. 2007). Among these tools, NMR method is able to provide a wide range of many molecular classes including sugars, amino acids, organic acids, alcohols or polyols, amine and ketones (Wishart, 2008).

P. oxalicum T3.3 had shown a promising antagonism in producing antifungal secondary metabolites that could inhibit the growth of C. gloeosporioides. Thus, the aim of this study was to determine the effect of different types of carbon sources for the production of antifungal compounds from P. oxalicum T3.3 against C. gloeosporiodes. Metabolomics approach was employed in identifying the possible compounds produced by theT3.3 strain exposed to the different carbon sources.