Characterization and Genetic Analysis of a Newly-Isolated Pigmentation Mutant of Neurospora crassa

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Hall, Michele Deleann
ETD; Neurospora crassa; Pigmentation; Genetic analysis; Biochemistry, Biophysics, and Structural Biology; Biology; Legacy ETDs
thesis / dissertation description
The branched biosynthetic carotenoid pathway in Neurospora crassa produces two end products: red neurosporaxanthin and yellow gamma-carotene. The orange pigmentation of the wild type strain is a mixture of these two pigments. The various pigmentation mutants of Neurospora crassa may exhibit a lack of carotenoids, an over-abundance of carotenoids or an alteration of the normal wild type strain coloration. The value of these mutants has been in elucidating details of the carotenoid pathway and its genetic control as well as supplying information about blue-light induction of carotenoid synthesis in the mycelium. Blue light also plays a role in induction of light-promoted conidiation. A new mutant of N. crassa. SS-692, was isolated in the Georgia Southern University Neurospora Genetics laboratory following U.V. irradiation. This mutant exhibits a vivid dark reddish-orange pigmentation and demonstrates an increase in production of conidia as compared to the wild type strain. Backcrosses of SS-692 to wild type, established a 1:1 segregation of the mutant and wild type progeny. Crosses to the alcoy tester strain indicated SS-692 was in Linkage Group III (LG III) or Linkage Group VI (LG VI). Additional crosses placed SS-692 in LG VI, linked to the yellow pigmentation mutant, ylo-1. as close as 1.6 map units. Both classical genetic crosses to tester strains and molecular studies utilizing chromosomal walking have narrowed the location of the mutant to the left of the ylo-1 locus.