The Genomic Regions That Contain Ochratoxin A Biosynthetic Genes Widely Differ in Aspergillus Section Circumdati Species

Abstract

Aspergillus section Circumdati includes 27 species, some of which are considered ochratoxin A (OTA) producers. However, there is considerable controversy about their potential OTA synthesis ability. In this work, the complete genomes of 13 species of Aspergillus section Circumdati were analyzed in order to study the cluster of OTA biosynthetic genes and the region was compared to those previously reported in A. steynii and A. westerdijkiae. The results obtained reveal that the genomes of some species in this section, including A. affinis, A. cretensis, A. elegans, A. muricatus, A. pulvericola, A. roseoglobulosus, and A. subramanianii, contain a potentially functional OTA biosynthetic cluster. Therefore, they might be able to synthesize the toxin. On the contrary, A. melleus, A. ochraceus, A. ostianus, A. persii, A. sclerotiorum, A. sesamicola, and A. westlandensis contain a truncated version of the cluster that lacks many of the genes involved in OTA biosynthesis, which might be related to their inability to produce OTA. The gain/loss pattern is different in all species, which suggests that the genetic evolution of this region might be due to independent events.

Evidence of the Involvement of a Cyclase Gene in the Biosynthesis of Ochratoxin A in Aspergillus carbonarius

“…Toxins 2021, 13, 892 2 of 13 Fungal genome sequencing has great utility for the identification of secondary metabolite gene clusters for known and novel compounds [8,9]. This kind of genomic approach has led to the identification of the clustered OTA biosynthetic genes, primarily in A. niger, and subsequently in A. carbonarius [10,11] and recently in several other OTA producing species [12,13]. In particular, the genomic analysis of A. carbonarius revealed the crucial role of three genes (otaA-AcOTApks, otaB-AcOTAnrps, and otaD-AcOTAhal) in the OTA biosynthesis [14][15][16].…”

“…The essential role of these five core genes in OTA biosynthesis has also been consolidated by the gene knockout approach. Moreover, a comparative analysis of OTA-biosynthetic clusters in A. steynii, A. westerdijkiae, A. niger, A. carbonarius, and P. nordicum has revealed a high synteny in cluster organization [13]. A detailed comparative analysis of Aspergilli genomes has recently led us to identify a gene whose sequence encoded a predicted protein similar to bacterial polyketide cyclases.…”

Predictive Modeling and Validation on Growth, Production of Asexual Spores and Ochratoxin A of Aspergillus Ochraceus Group under Abiotic Climatic Variables

“…Two ochratoxigenic strains very similar in morphology (colony and microscopic characteristics), but with variations in their responses to environmental conditions in terms of OTA biosynthesis regulation [ 28 ] from the group of A. ochraceus within section Circumdati ( A. steynii IBT 23096, and A. westerdijkiae IBT 23971) were used in the experimental work of this study. Prof. J. Frisvad (Tech.…”

AwAreA Regulates Morphological Development, Ochratoxin A Production, and Fungal Pathogenicity of Food Spoilage Fungus Aspergillus westerdijkiae Revealed by an Efficient Gene Targeting System

“…Aspergillus westerdijkiae is one of the most notorious ochratoxigenic fungi contaminating cereal, fruit, salted meat, and cheese. Several isolates identified as the original OTA-producing A. ochraceus were reclassified as A. westerdijkiae ( Frisvad, 2004 ; Gil-Serna et al, 2009 , 2020 ), showing its critical roles in OTA contamination. Here, we established the uridine auxotrophic A. westerdijkiae and further developed an efficient gene targeting system by disruption of Awku70 and Awlig4 in the NHEJ pathway.…”