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Media type:
E-Article
Title:
Pheromones Are Essential for Male Fertility and Sufficient To Direct Chemotropic Polarized Growth of Trichogynes during Mating in Neurospora crassa
Contributor:
Kim, Hyojeong;
Borkovich, Katherine A.
imprint:
American Society for Microbiology, 2006
Published in:Eukaryotic Cell
Language:
English
DOI:
10.1128/ec.5.3.544-554.2006
ISSN:
1535-9778;
1535-9786
Origination:
Footnote:
Description:
<jats:title>ABSTRACT</jats:title>
<jats:p>
<jats:italic>Neurospora crassa</jats:italic>
is a self-sterile filamentous fungus with two mating types,
<jats:italic>mat A</jats:italic>
and
<jats:italic>mat a</jats:italic>
. Its mating involves chemotropic polarized growth of female-specific hyphae (trichogynes) toward male cells of the opposite mating type in a process involving pheromones and receptors.
<jats:italic>mat A</jats:italic>
cells express the
<jats:italic>ccg-4</jats:italic>
pheromone and the
<jats:italic>pre-1</jats:italic>
receptor, while
<jats:italic>mat a</jats:italic>
strains produce mRNA for the pheromone
<jats:italic>mfa-1</jats:italic>
and the
<jats:italic>pre-2</jats:italic>
receptor; MFA-1 and CCG-4 are the predicted ligands for PRE-1 and PRE-2, respectively. In this study, we generated Δ
<jats:italic>ccg-4</jats:italic>
and Δ
<jats:italic>mfa-1</jats:italic>
mutants and engineered a
<jats:italic>mat a</jats:italic>
strain to coexpress
<jats:italic>ccg-4</jats:italic>
and its receptor,
<jats:italic>pre-2</jats:italic>
. As males, Δ
<jats:italic>ccg-4 mat A</jats:italic>
and Δ
<jats:italic>mfa-1 mat a</jats:italic>
mutants were unable to attract
<jats:italic>mat a</jats:italic>
and
<jats:italic>mat A</jats:italic>
trichogynes, respectively, and consequently failed to initiate fruiting body (perithecial) development or produce meiotic spores (ascospores). In contrast, Δ
<jats:italic>ccg-4 mat a</jats:italic>
and Δ
<jats:italic>mfa-1 mat A</jats:italic>
mutants exhibited normal chemotropic attraction and male fertility. Δ
<jats:italic>ccg-4</jats:italic>
Δ
<jats:italic>mfa-1</jats:italic>
double mutants displayed defective chemotropism and male sterility in both mating types. Heterologous expression of
<jats:italic>ccg-4</jats:italic>
enabled
<jats:italic>mat a</jats:italic>
males to attract
<jats:italic>mat a</jats:italic>
trichogynes, although subsequent perithecial differentiation did not occur. Expression of
<jats:italic>ccg-4</jats:italic>
and
<jats:italic>pre-2</jats:italic>
in the same strain triggered self-stimulation, resulting in formation of barren perithecia with no ascospores. Our results indicate that CCG-4 and MFA-1 are required for mating-type-specific male fertility and that pheromones (and receptors) are initial determinants for sexual identity during mate recognition. Furthermore, a self-attraction signal can be transmitted within a strain that expresses a pheromone and its cognate receptor.
</jats:p>