Identification of genes induced in alkaloid producing cultures of Claviceps sp

• Published in: Current genetics Vol. 31; no. 4; pp. 357 - 360
• Main Authors: Arntz, C, Tudzynski, P
• Format: Journal Article
• Language: English
• Published: United States 01.04.1997
• Subjects: ALCALOIDE; ALCALOIDES; ALKALOIDS; Alkaloids - metabolism; Amino Acid Sequence; amino acid sequences; biosynthesis; Blotting, Northern; Cell Differentiation; Cell Differentiation - genetics; Claviceps; Claviceps - genetics; Claviceps - metabolism; CLAVICEPS FUSIFORMIS; CLAVICEPS PURPUREA; Cloning, Molecular; complementary DNA; DMAT-S; DNA libraries; DNA, Complementary; DNA, Complementary - genetics; enzymes; ERGOT ALKALOIDS; GENE; Gene Expression Regulation, Fungal; Gene Library; GENES; Genes, Fungal; genetics; HYDROPHOBINS; metabolism; Molecular Sequence Data; NEUROSPORA CRASSA; Neurospora crassa - genetics; nucleotide sequences; proteins; Sequence Homology, Amino Acid; STRESS PROTEIN; TRICHODERMA HARZIANUM
• ISSN: 0172-8083; 1432-0983
• DOI: 10.1007/s002940050216

In order to identify genes which are expressed during alkaloid synthesis in an axenic culture of Claviceps sp. (strain ATCC 26245), a cDNA library from a producing culture was differentially screened with cDNA from producing (cDNA+) and non-producing (cDNA-) cultures, respectively. Altogether, ten cDNA clones were obtained, the alkaloid-synthesis-correlated expression of which was confirmed by Northern analyses. Evaluation of their nucleotide and derived amino-acid sequences identified one gene unequivocally, coding for dimethylallyltryptophan-synthase (DMAT-S), the initial enzyme of the specific alkaloid pathway. For two other genes significant homologies to known fungal genes were detected: one clone showed homology to the Neurospora crassa ccg1 gene, coding for a clock-regulated putative general stress protein; seven cDNA clones, derived from the same gene, which is highly expressed under these conditions, contained typical hydrophobin domains and long stretches of asparagine/glycine repeats (like QID3 from Trichoderma harzianum), thus probably representing a cell-wall constituent. These data show that this is not only a successful approach to clone genes specific for the alkaloid-pathway of C. purpurea, but also of genes which might be involved in the differentiation of sclerotial hyphae, the prerequisite for alkaloid synthesis.