ARS | Publication request: CHARACTERIZATION OF FUSARIUM VERTICILLIOIDES ALTERNATIVELY SPLICED AND OTHER ESTS

Submitted to: Fungal Genetics Conference/Asilomar
Publication Type: Abstract Only
Publication Acceptance Date: March 20, 2005
Publication Date: March 20, 2005
Citation: Brown, D.W., Proctor, R., Butchko, R.A., Cheung, F., Town, C., Kendra, D.F. 2005. Characterization of Fusarium verticillioides alternatively spliced and other ESTs [abstract]. Proceedings of the 23rd Fungal Genetics Conference. p. 189.

Technical Abstract: Fusarium verticillioides is a pathogen of maize worldwide and produces fumonisins, a family of mycotoxins that have been associated with several animal diseases and cancer in humans. The fumonisin biosynthetic genes are located in a co-regulated 15-member gene cluster spanning 43 kb of genomic sequence. In order to identify genes that regulate fumonisin biosynthesis and that are involved in the F. verticillioides-maize interactions, we generated over 87,000 expressed sequence tags (ESTs) that represent 11,119 unique sequences from nine cDNA libraries prepared from the fungus grown under fumonisin-inducing and non-inducing conditions and in the presence of maize tissues. Of particular interest, we found that 78 of the 700 ESTs that match portions of the 15 fumonisin genes were alternative splice forms (ASFs). Most ASFs are predicted to yield truncated proteins due to stop codons and/or frameshifts in the retained introns or the altered sequence due splice events utilizing an alternate 3’ border. We found that the ASFs appeared to be differentially expressed as more were present in libraries derived from older cultures. This, coupled with the high frequency of occurrence of some ASFs suggests they serve a biological role. We have begun to examine the occurrence of ASFs in culture over time using microarrays. The physiological importance of alternative splicing in fungi has not been determined. Understanding their role in fumonisin biosynthesis may open up new avenues to develop strategies to limit fumonisin contamination of agricultural commodities.