Undergraduate research opportunities for Spring 2014 (and beyond)

Our lab will have two research opportunities for undergraduates in spring 2014 (with potential to extend into the summer and beyond), both involving cultural studies of fungi. Please read below for details of the positions, and how to get involved.

Project 1: Mycorrhizal synthesis studies in Boletinellus merulioides (the “ash bolete”) and Fraxinus americana (white ash). Background: Boletinellus merulioides is a mushroom-forming fungus that occurs almost exclusively in association with ash trees. The nutritional mode of B. merulioides is controversial, with some authors suggesting that it forms mycorrhizal associations with ash (in which the fungus receives sugars from the tree, which then benefits by enhanced uptake of mineral nutrients). In a pilot study, PhD student Mitchell Nuhn has developed methods to germinate F. americana seeds in culture (on agar) and then co-inoculate F. americana and B. merulioides onto peat-vermiculite. Preliminary results suggested that survivorship of F. americana seedlings is enhanced in the presence of B. merulioides, implying that there is indeed a symbiotic association between the two species, but the sample size was insufficient to achieve a statistically significant result. Scope of the project: You will receive training in methods for germinating F. americana seedlings (an admittedly tedious process that requires that the plant embryos be dissected out of the seeds) and establishing the co-culture with B. merulioides. You will establish a large number of seedlings with and without the fungus partner, record survivorship data at several time points after inoculation, and assist in statistical analyses of the data. This project will be conducted under the direction of Mitchell Nuhn and David Hibbett.

Boletinellus merulioides. Photo by Mitchell Nuhn.

Boletinellus merulioides. Photo by Mitchell Nuhn.

Project 2: Genetics of fruiting body development in Lentinus tigrinus. Background: Lentinus tigrinus is a mushroom-forming fungus that occurs in two forms in nature, one “agaricoid” and the other “secotioid”. Both forms are “pileate-stipitate”, meaning that they have a cap and a stalk. The agaricoid form has exposed gills that release spores to the air, whereas the secotioid form has a layer of tissue that encloses the spore-bearing structures. Thus, spores are not released into the air by the secotioid form. Previous work has suggested that the secotioid form is conferred by a recessive allele at a single locus, and recently whole genome sequences have been produced for two monokaryons (haploids), one with the secotioid allele and the other with the agaricoid allele. Master’s student Alexis Carlson has developed methods to perform controlled crosses of L. tigrinus and produce mushrooms in culture. Scope of the project: You will receive training in methods for growing L. tigrinus in culture, including isolation of monokaryotic single-spore isolates and fruiting of mushrooms in culture. You will perform back-crosses to tester strains to genotype the isolates with respect to the fruiting body locus (and in the process confirm that this is a unifactorial trait). You will then extract DNA from the genotyped SSIs, which may be used later in bulk segregant analysis to identify the secotioid locus. This project will be conducted under the direction of Alexis Carlson and David Hibbett.

The "secotioid" form of L. tigrinus. The "agaricoid" form woudl have gills visilble below the cap. Photo by Alexis Carlson/Laszlo Nagy.

The “secotioid” form of L. tigrinus fruited in culture. The “agaricoid” form would have gills visible below the cap. Photo by Alexis Carlson/Laszlo Nagy.

Both projects will provide training in microbiological techniques and have potential to be expanded into long-term projects (including Master’s projects). Project 1 may be of particular interest to students with interests in environmental biology, plant biology, and fungal ecology, while Project 2 may be more appropriate for students with interests in genetics, developmental biology and genomics. Both projects require attention to detail, excellent organizational skills, and manual dexterity. As a member of our lab group, you would be expected to attend weekly (or semi-weekly) lab meetings, and you would be invited to come along on field trips and mushroom forays. Our lab includes a friendly group of students and post-docs at various career stages, with very diverse interests. We are always looking for students who are curious about the natural world and enjoy working in groups. Academic credit may be arranged through a Directed Study course (BIOL/ES/BCMB 299).

To apply, please send an e-mail to David Hibbett. Indicate if you have a preference for either project, and include a list of the Biology courses that you have taken, and the name of one Clark-based reference (ideally, someone who has worked with you in a lab setting, such as a Teaching Assistant). Please also feel free to get in touch with questions.

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