Molecular characterization of aflatoxigenic and non-aflatoxigenic Aspergillus flavus isolates collected from corn grains

Abstract

ABSTRACT. Twelve species from six fungal genera were found to be associated with corn (Zea mays L.) grain samples collected from three main regions of Saudi Arabia. The average frequencies of the most common genera were Aspergillus (11.4%), Fusarium (9.5%), Penicillium (5.1%), and Alternaria (5.8%). Fifteen isolates of Aspergillus flavus were screened by HPLC for their ability to produce aflatoxins (AF). The percentage of aflatoxigenic A. flavus isolates was 53%. Eight isolates produced AF, at concentrations ranging 0.7-2.9 ppb. Random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) molecular markers were used to genetically characterize isolates of A. flavus and to discriminate between the aflatoxigenic and non-aflatoxigenic isolates. RAPD and ISSR analysis revealed a high level of genetic diversity in the A. flavus population, which was useful for genetic characterization. The clustering in the RAPD and ISSR dendrograms obtained was unrelated to geographic origin. The RAPD and ISSR markers could not discriminate between aflatoxigenic and non-aflatoxigenic isolates, but the ISSR primers were somewhat better.

Genetic diversity analysis of Aspergillus flavus isolates from plants and air by ISSR markers

“…Aspergillosis is an umbrella term used to describe a wide range of diseases of human and animals (Schabereiter-Gurtner et al, 2007). A. flavus has a broad host range and acts as an opportunistic pathogen/saprobe for any crop seed (wheat, corn, sorghum, cotton, rice, and peanut) (Klich, 2007;Mahmoud, 2014).…”

“…All isolates were from Saudi Arabia, except for five isolates from Egypt. A. flavus isolates were maintained and the production of mycelia was performed as described by Mahmoud et al (2014).…”

“…The delicate analysis of genetic diversity has considerable implications for molecular plant breeding strategies and biological control in plant disease programs (Kumar, 1999). Recently, advanced molecular biology techniques, such as DNA profiling based on amplified fragment length polymorphisms (AFLP) , restriction fragment length polymorphisms (RFLPs) (Mohankumar, et al, 2010), random amplification of polymorphic DNA (RAPD) (Mahmoud et al, 2014), microsatellites or simple sequence repeats (SSR) (Mushtaq et al, 2015), expressed sequence tag-simple sequence repeats (EST-SSR) (Wang et al, 2012), short tandem repeats (STR) (Houshyarfard et al, 2015), and intersimple sequence repeats (ISSR) (Zhang et al, 2013;Chhotaray et al, 2015), have been widely used for the characterization of genetic diversity in A. flavus.…”

“…In plant-pathogenic fungi, ISSR technology has been used to characterize genetic diversity (Mahmoud et al, 2014), genetic structure (Rampersad, 2013;Gramaje et al, 2014), fingerprinting (identification) (Priyanka et al, 2014), population genetic structure (Hadrich et al, 2010), phylogenetic studies (Dutech et al, 2007), genome mapping (Chakravarty, 2011), and gene tagging (Ratnaparkhe et al, 1998).…”

Expression of genes encoding cellulolytic enzymes in some Aspergillus species

“…The six isolates were obtained from grains, seeds, and soil of agricultural crops. They were maintained under conditions as previously described (Mahmoud et al, 2014). …”