|Hohn, Thomas - NOVARTIS AGRIBUS BIOTECH|
Submitted to: Society of Industrial Microbiology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: August 6, 1999
Publication Date: N/A
Technical Abstract: A significant portion of isoprenoid pathway carbon flow in the filamentous fungi Fusarium sporotrichioides is utilized in the production of sesquiterpenoid toxins known as trichothecenes. Our efforts have focused on determining whether isoprenoid precursors (namely, farnesyl diphosphate) normally channeled into trichothecene production can be utilized to produce commercially valuable compounds such as carotenoids. By disrupting the gene encoding for trichodiene synthase (Tri5), the enzyme catalyzing the first committed step of trichothecene biosynthesis, a trichothecene-deficient mutant of F. sporotrichioides (Tri5**-) was generated. Tri5**- was transformed using gene cassettes containing multiple chimeric carotenoid biosynthetic genes. Tri5 promoter and terminator sequences were added to Erwinia uredovora carotenoid biosynthetic genes to regulate expression, and the chimeric genes were assembled into multi-gene cassettes using complementary SfiI and DraIII restriction sites. The gene cassettes integrated into the fungal genome as intact units in several transformants. The introduced carotenoid biosynthetic genes were expressed at levels comparable to those observed for endogenous trichothecene biosynthetic genes. In addition, coordinate expression of carotenoid and upstream isoprenoid biosynthetic genes was observed. Lycopene and beta-carotene producing strains of F. sporotrichioides have been developed thus far.