Review on Citrinin: Synthetic Methods, Molecular Biosynthesis and Effect of Plant Extracts.

Introduction: Citrinin is a mycotoxin originally isolated from Penicillium citrinum. It has been found to be produced by a variety of other fungi (Aspergillus niveus, Aspergillus ochraceus, Aspergillus oryzae, Aspergillus terreus, Monascus ruber, Monascus purpureus and Penicillium camemberti) which are found or used in the production of human foods (Abramson et al., 1999). The inhibitory effect of plant extracts on citrinin biosynthesis have been examined (Mossini and Kemmelmeier, 2008; Reddy et al., 2010). They found that all the tested plant extracts reduced the citrinin production. Shimizu et al. (2005, 2007) found that the pksCT gene was essential for citrinin biosynthesis in M. purpureus. Also Sakai et al. (2008) reported that introducing additional copies of an activator gene (ctnA), controlled by the Aspergillus nidulans trpC promoter, into the citrinin-cluster-containing transformants enhanced the transcription of all the genes in the cluster and resulted in an almost 400-fold higher citrinin production compared to that of the parental transformant. Aims: To give idea on physicochemical properties of citrinin, its production, effects of some plant extracts on it and gene involved in citrinin biosynthesis. Study Design: Review study. Place and Duration of Study: Department of Biology, Faculty of Science, Taif- Saudi Arabia and Department of Botany, Faculty of Science, Tanta-Egypt. 2011-2012. Methodology: Citrinin was produced in liquid potato-dextrose medium (PD) or in glucose medium. The citrinin was extracted three times with chloroform (1:1 v/v), pooled and concentrated in vacuo at 40ºC using a rotary evaporator. The crude extract was diluted in minimum amount of chloroform (2 ml) and citrinin was estimated by thin layer chromatography (TLC). Effects of some plant extracts like neem leaf extract and some medicinal plants were determined. Conclusion: This review was written with the aim of demonstrating the scope of citrinin production, various analytical techniques in citrinin detection and estimation and effects of some plant extracts and genes on citrinin biosynthesis. It was found that plant extracts can be used as a potential source of sustainable ecofriendly botanical fungicides to protect food grains from toxigenic P. citrinum and citrinin accumulation under storage conditions.

Fungal Control of Pathogenic Fungi Isolated From Some Wild Plants in Taif Governorate, Saudi Arabia

Twenty two plants were collected from Taif Governorate and identified as: Aerva lanata, Arnebia hispidissima, Artemisia judaica, Artemisia monosperma, Asphodelus aestives, Avena barbata, Capparis dcidua, Eucalyptus globulus, Euphorbia glomerifera, Foeniculum vulgare, Forsskaolea tenacissima, Juniperus procera, Launaea mucronata, Launaea sonchoides, Medicago sativa, Opuntia ficus, Phagnalon sinaicum, Prunus persica, Pulicaria crispa, Punica granatum, Rumex dentatus and Trichodesma calathiforme. Pathogenic fungi were isolated from some of these plants and identified as Alternaria alternata, Cephalosporium madurae, Cladosporium herbarum, Fusarium oxysporum, Humicola grisea, Penicillium chrysogenum and Ulocladium botrytis. Four antagonistic isolates were tested, 2 from Gliocladium fungus and 2 from Trichoderma fungus. We found that all the four antagonistic isolates (G. deliquescens, G. virens, T. viride and T.hamatum) significantly inhibited the radial growth of the pathogenic fungi tested, with different ratios. The results indicated that the antibiotics produced by the antagonists were more effective than the fungus itself and differ with different fungi. Coating plant stems with antagonists or with antagonist extracts reduce the severity of the disease but not prevent it in all tested pathogens.