The gene for a lectin-like protein is transcriptionally activated during sexual development, but is not essential for fruiting body formation in the filamentous fungus <it>Sordaria macrospora</it>

• Main Authors: Cebula Patricia, Nowrousian Minou
• Format: Article
• Language: English
• Published: BMC 2005-11-01
• Series: BMC Microbiology
• Online Access: http://www.biomedcentral.com/1471-2180/5/64

<p>Abstract</p> <p>Background</p> <p>The filamentous fungus <it>Sordaria macrospora </it>forms complex three-dimensional fruiting bodies called perithecia that protect the developing ascospores and ensure their proper discharge. In previous microarray analyses, several genes have been identified that are downregulated in sterile mutants compared to the wild type. Among these genes was <it>tap1 </it>(<it>t</it>ranscript <it>a</it>ssociated with <it>p</it>erithecial development), a gene encoding a putative lectin homolog.</p> <p>Results</p> <p>Analysis of <it>tap1 </it>transcript levels in the wild type under conditions allowing only vegetative growth compared to conditions that lead to fruiting body development showed that <it>tap1 </it>is not only downregulated in developmental mutants but is also upregulated in the wild type during fruiting body development. We have cloned and sequenced a 3.2 kb fragment of genomic DNA containing the <it>tap1 </it>open reading frame and adjoining sequences. The genomic region comprising <it>tap1 </it>is syntenic to its homologous region in the closely related filamentous fungus <it>Neurospora crassa</it>. To determine whether <it>tap1 </it>is involved in fruiting body development in <it>S. macrospora</it>, a knockout construct was generated in which the <it>tap1 </it>open reading frame was replaced by the hygromycin B resistance gene <it>hph </it>under the control of fungal regulatory regions. Transformation of the <it>S. macrospora </it>wild type with this construct resulted in a <it>tap1 </it>deletion strain where <it>tap1 </it>had been replaced by the <it>hph </it>cassette. The knockout strain displayed no phenotypic differences under conditions of vegetative growth and sexual development when compared to the wild type. Double mutants carrying the Δ<it>tap1 </it>allele in several developmental mutant backgrounds were phenotypically similar to the corresponding developmental mutant strains.</p> <p>Conclusion</p> <p>The <it>tap1 </it>transcript is strongly upregulated during sexual development in <it>S. macrospora</it>; however, analysis of a <it>tap1 </it>knockout strain shows that <it>tap1 </it>is not essential for fruiting body formation in <it>S. macrospora</it>.</p>