A. niger lacks tricarboxylate transporter FUM 11 present in Fusarium verticillioides, but A. niger has the biochemical ability to produce citric acid and probably recruit the tricarballylic acid via the citric acid biosynthesis. Fumonisin is, however, a small fraction of the output of organic acids on a molar basis. Since most strains of A. niger produce fumonisins it is a possibility to use isolates of other species closely related to A. niger, such as A. tubingensis, A. acidus, A. brasiliensis or A. vadensis, none of which produce fumonisins or ochratoxins. As can be seen from the Table S4, these species have also been used for citric acid production. Indeed, several strains have been used by the industry as ����A. niger����, but have here been shown to represent some of the latter species. Among the non-fumonisin producing A. niger are NRRL 321, 335, 340, 593 and 595, these were only listed in the original paper on citric acid producing black Aspergilli and have not been used for industrial purposes. NRRL 595 has been used infrequently, however. Despite the availability of other fungi in biotechnology as industrial work-horses, it is Aspergillus niger sensu stricto that has been used most extensively, also stressed by that fact that it has been genome sequenced three times. The fact that A. niger has been given GRAS status in many industrial applications could be questioned by the fact that most strains of A. niger produce fumonisins and some of them in addition OTA, both potentially carcinogenic mycotoxins, on laboratory media. Our findings that some of these industrially used A. niger strains can produce these two mycotoxins, at conditions mimicking industrial citric acid production conditions, strongly emphasizes the need for analytical control for Publications Using Abomle VE-822 securing the absence of mycotoxins in the final industrial products. Currently no validated methods for the analysis of the two toxins in fermentation products have been published, and we highly recommend developing such methods. Altogether we analyzed all available strains of industrially used A. niger, and found a surprisingly high frequency of effective fumonisin producers among them. With the recent development of advanced gene targeting methods in filamentous fungi, site-specific point mutations in essential genes required for production of fumonisin and ochratoxin in Aspergillus niger should be used in order to avoid any mycotoxin production in industrial products. Accurate intron excision and exon joining during the process of pre-mRNA splicing, enable generation of mature mRNAs that contain continuous coding sequence for protein synthesis. Precise pre-mRNA splicing depends on the presence of splicing consensus sequences at 59 and 39 exon splice sites and additional intronic and exonic regulatory elements. These elements are defined as Splicing Enhancer or Silencers according to their effect on splice site selection and are involved in normal and aberrant splicing regulation. Differently from classical splice sites, enhancers and silencers are highly degenerated sequences that affect splicing through their interaction with regulatory splicing factors and/or RNA secondary structure. RNA-binding factors are key splicing regulators as their interaction with intronic and/or exonic sequences contributes to the splicing outcome. In general, each splicing factor has a positive or a negative effect on splicing, for example SR proteins are considered enhancers whereas hnRNPA1/A2 are silencers.