Genes Controlling Pigmentation in Nectria haematococca

Abstract

The Sl homothallic wild-type strain of Nectria haematococca produces grey-purplish colonies on PDA medium, due to synthesis of fusarubin and related naphthazarins. Seventeen yellow, beige or white mutants were isolated. On the basis of recombination tests they were divided into six distinct chromosomal regions. Four of them, designated befB, befC, belB and belC, may be regarded as regulatory genes which uncouple the processes of ageing and pigmentation that are normally associated in the wild-type. The two others, alyA and yelJ-beiW, control the biosynthesis of naphthazarins. Mutations in alyA were found epistatic to yelJ and beiW mutations, indicating that the aZyA locus acts on an earlier biosynthetic step than the yelJ-bei W region. The latter was shown to comprise two closely linked genes, yielding yellow or beige colours when mutated. Analysis of polar mutations suggests that they form a single unit of transcription. One of these two genes probably controls a late oxidation step in naphthazarin biosynthesis.

Novel Polyketide Synthase from Nectria haematococca

“…When PR1, a transformant with a wildtype phenotype, was crossed with [a‫ء‬ 58 ], which produces red fertile perithecia, a preliminary analysis of a sample of descendants from each perithecium collected on the line of contact was required to distinguish hybrids from parental perithecia (11). The progeny from two hybrid perithecia (250 ascospores from each perithecium) were analyzed for color marker segregation (3,40), although these progeny may not all have originated from independent meiotic events.…”

“…strain CBS 225.58 have been described elsewhere (3,40). When PR1, a transformant with a wildtype phenotype, was crossed with [a‫ء‬ 58 ], which produces red fertile perithecia, a preliminary analysis of a sample of descendants from each perithecium collected on the line of contact was required to distinguish hybrids from parental perithecia (11).…”

“…In Nectria haematococca, mutants in which the pigmentation of mycelia and perithecia is affected (i.e., mutants either show hyperproduction of red pigments or are albinos) have been obtained through mutagenesis (11,40,41). Extensive genetic analyses of such mutants have been conducted (11,40). It has been established that at least six distinct loci control mycelial pigmentation.…”

“…Relatively little is known about the biosynthesis of red pigments, with the exception of the bikaverin produced by Gibberella fujikuroi (31). In Nectria haematococca, mutants in which the pigmentation of mycelia and perithecia is affected (i.e., mutants either show hyperproduction of red pigments or are albinos) have been obtained through mutagenesis (11,40,41). Extensive genetic analyses of such mutants have been conducted (11,40).…”

19 F Nuclear Magnetic Resonance Analysis of 5-Fluorouracil Metabolism in Four Differently Pigmented Strains of Nectria haematococca

“…metabolites. The beiW88 strain was known to carry only one mutation preventing pigment biosynthesis (11). It was supposed that active pigment biosynthesis might result in various disorders in other areas of metabolism.…”