Characterization of a Morphological Mutant, M-134, and Two Conidia-shed Mutants, E-1 and K-44 of <em>Neurospora crassa</em>

<p>Following ultraviolet irradiation M-134, a crisp mutant strain and two conidial-shed mutants, E-l and K-44, of <em>Neurospora crassa</em>, were isolated in the Georgia Southern University Neurospora Laboratory. Using scanning electron microscopy differences in morphology among M-134 and other crisp mutants, <em>cr-1</em>, <em>cr-2</em>,<em> cr-3</em>, <em>cr-4</em>, <em>cr-5</em>, and wild type <em>N. crassa</em> were compared. The SEM study revealed that M-134 and the other five crisp mutants all exhibit a reduced mycelial mat and clumps of conidia leading to their crisp-like morphology. Previous preliminary mapping of M-134 indicated that the mutant is in Linkage Group 1 and linked to <em>lys -4</em> by 9% recombination. The present study also mapped M-134 to the right of <em>lys-4</em> in Linkage Group 1 with the gene order <em>cys-9</em> M-134 <em>im-1</em> displaying 15.4% recombination between M-134 and <em>cys-9</em> and 5.7% recombination between M-134 and <em>un-1</em> thus should be designated <em>cr-6</em>.</p> <p>When E-l and K-44 were compared to the wild type strain, these mutants failed to shed conidia when the culture tubes were inverted and sharply tapped (the tap test), whereas the conidia of wild type produced a visible cloud. Previous SEM indicated that E-l and K-44 conidia stayed in proconidial chains. The present SEM study includes an examination of E-l and K-44, and a comparison between the mutants and <em>csp-1</em> and <em>csp-2</em> using wild type as the control. All four of these mutants examined showed conidia staying in proconidial chain whereas the wild type conidia separate from the chains.</p> <p>Earlier work had shown that crosses of K-44 and E-l to wild type exhibited 1:1 segregation, indicating single genes following Mendelian inheritance. However, no attempts to map the mutants had been made. To begin mapping, K-44 and E-l were crossed to the alcoy tester strain which facilitates mapping mutants to Linkage groups I-VI. Failure to show linkage of either mutant to the six tested linkage groups assumes that both mutants were in the seventh linkage group (LG VII). Since no linkage was found in LG I-VI, both mutants were then crossed to <em>csp-2</em>, located in LG VII to determine allelism and linkage to the mutant. Both crosses produced wild type progeny, ruling out allelism of E-l and K-44 to <em>csp-2</em>. E-l displayed linkage to <em>csp-2</em> with 37.6% recombination and should be designated <em>csp-3</em>. K-44 showed no linkage to <em>csp-2</em> and was therefore crossed to <em>mc-3</em> located in a different part of LG VII also resulting in no linkage.</p>

Name thesis:degree_name

Master of Science in Biology

Level thesis:degree_level

Thesis (restricted to Georgia Southern)

Discipline thesis:degree_discipline

Department of Biology

Year dc:date.available

2003

Author dc:creator

• Digby, Gregory Julian

Contributors dc:contributor

• Wayne A. Krissinger
• Don Drapalik

• ETD
• Morphology
• Genetic analysis
• Neurospora crassa
• Biochemistry, Biophysics, and Structural Biology
• Biology

Repository record dc:identifier

https://digitalcommons.georgiasouthern.edu/etd_legacy/67

OAI identifier oai:identifier

oai:digitalcommons.georgiasouthern.edu:etd_legacy-1080