Henry Purnell

Document Type


Publication Date



Due to its small genome and dominant haploid life stage, Physcomitrium patens (formerly Physcomitrella patens) has become a model organism for studying plant genetics. The focus of this study was the Cellulose Synthase gene superfamily of P.patens, specifically the Cellulose Synthase-Like Ds (CSLD) family of genes. Previous studies into CSLD genes were preformed using RNA interference (RNAi) to preform a loss of function analysis on the entire PpCSLD gene family. The loss of function of the CSLD gene family resulted in inhibited protonemal tip growth indicating the CSLD gene family may regulate protonema formation. To further study the function of the CSLD genes in P.patens gene knockout (KO) of the CSLD5 and CSLD8 genes is preformed using CRISPR/Cas9 transformations. Over the summer analysis of the sg1 and sg2 cut sites was preformed on potential CSLD5/8 double knockouts from two different transformations, totaling 140 potential mutants being screened. Screening was preformed using competition-based PCR (cbPCR). When preformed on wild type P.patens the cbPCR primers result in a greater ratio of forward inner primer product (around 564bps) to forward outer primer product (around 840bps), allowing for the screening of mutants by running the cbPCR products on agarose gels and determining the number of base pairs in the final PCR product via electrophoresis with a molecular weight ruler as reference.

Faculty Mentor

Michael Budziszek, Ph.D.

Academic Discipline

College of Arts & Sciences



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