Thesis (Ph. D.)--University of Wisconsin--Madison, 1967. / Typescript. Includes reprint of A salivation factor from Rhizoctonia leguminicola [by] Barbara J. Whitlock, D.P. Rainey ... [et al.], Tetrahedron letters, no. 32, pp. 3819-3824, 1966. Vita. Includes bibliographical references.

Thesis--Wisconsin. / Vita. Bibliography; leaves 120-130.

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The City of Saskatoon is challenged with large quantities of wood wastes such as demolition wastes, construction wastes, and elm tree trims. It has also been recently found that some of the elm trees in Saskatoon might have been infected with the Dutch elm disease, hence, this would lead to the cutting down of trees. The cutting of the affected elm trees will definitely increase the quantities of wood wastes in Saskatoon. The City of Saskatoon might therefore develop the initiative to develop more landfills, as all wood wastes are usually deposited into the landfills. Landfills are usually not environmental friendly, hence, no one wants a landfill in his backyard. Furthermore, the concerns about climate change is also a pressing issue around the world as individual countries most especially the industrialised countries are looking for means to reduce their carbon foot prints. The two issues discussed above have therefore developed the initiatives for renewable energy sources as an alternative to the burning of fossil fuel to produce energy. One of the common alternatives to burning of fossil fuel is the biomass fuel specifically the woody biomass fuel (wood chips). This project is therefore developed as one of the initiatives to evaluate the feasibility of wood chips as an energy source in Saskatoon.

Dutch elm disease (DED) is a debilitating wilt disease that has decimated elm populations globally. The current pandemic of this disease is caused by the ascomycete fungal pathogen Ophiostoma novo-ulmi. A number of strategies have been used to attempt to mitigate the effects of DED but none have met any sustainable success, and the disease continues to have severe ecological and economic impacts. Consequently, research focus has turned to the development of control strategies at the genetic level. One such genetic strategy is the use of naturally occurring fungal viruses (mycoviruses) to induce hypovirulence in their fungal hosts. Hypovirulence, or attenuation of fungal pathogenicity using mycoviruses, has been well studied in other systems but has yet to be developed for O. novo-ulmi. A candidate virus, OnuMV1c, was found in an isolate of O. novo-ulmi (93-1224) at the western Canadian disease front and its genome was sequenced. OnuMV1c is a mitochondrial virus and has a 3.1 kb single-stranded positive RNA genome that encodes an RNA-dependent RNA polymerase (RdRp) involved in its replication as a double-stranded RNA molecule. It exists in O. novo-ulmi mitochondria in both its single-stranded and double-stranded forms. Our research group identified OnuMV1c as a potential candidate for biological control of Dutch elm disease. Our long-term research goal is to use the virus as a means to activate the RNA interference pathway of O. novo-ulmi, leading to down-regulation of genes involved in pathogenicity. If OnuMV1c is engineered such that it carries an RNA interference cassette in addition to its own complement of genes, it could act as an enhanced hypovirus. RNA interference (RNAi) is a cytoplasmic process, and therefore in order to use OnuMV1c for RNAi the viral genome needed to be reprogrammed such that it could be expressed in the cytoplasm rather than the mitochondria. The objectives of my master’s research were to 1) genetically engineer OnuMV1c to express in the cytoplasm using a cDNA reverse genetics approach, and 2) test the functionality of the re-engineered cDNA OnuMV1c virus (MV1cCyt). The first objective was accomplished by modifying codons in the RdRp sequence of OnuMV1c such that the sequence could be translated in the cytoplasm. This genetically engineered cytoplasmic version of OnuMV1c, named MV1cCyt, was flanked with exogenous promoter and terminator sequences to drive its transcription. The entire construct was engineered as a cDNA molecule and was cloned into the fungal transformation vector pAN7-1, which was used to transform O. novo-ulmi protoplasts. The second objective was achieved through the use of strand-specific RT-PCR, a technique that allowed the detection of both the positive and negative strands of MV1cCyt. Results indicated that while four individual cell lineages contained MV1cCyt cDNA stably integrated into the nuclear genome, only one transformant was able to produce double-stranded MV1cCyt RNA. These results have important implications for the use of OnuMV1c as an engineered hypovirus and represent the first step towards the development of a biological control strategy for Dutch elm disease. / Graduate

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The banded elm bark beetle, Scolytus schevyrewi, was first observed in Canada in Alberta in 2006. In 2007, it was found in Manitoba and Saskatchewan. Its hosts include the American elm and so, it has the potential to transmit Dutch elm disease. The beetle was studied in six communities in 2009–2011 in Manitoba and Saskatchewan to learn about its biology in the Prairies. Baited sticky traps revealed that the adult flight period is from June until October, with a peak in late summer. Unbaited sticky traps and trap logs revealed that stressed Siberian elm is the preferred host. Although S. schevyrewi larvae overwintered successfully, 15% of the overwintering individuals emerged in the spring. The main impact of S. schevyrewi is expected to be the killing of stressed Siberian elms. Such trees should be removed to avoid population outbreaks that might result in attacks on healthy Siberian and American elms.

The banded elm bark beetle, Scolytus schevyrewi, was first observed in Canada in Alberta in 2006. In 2007, it was found in Manitoba and Saskatchewan. Its hosts include the American elm and so, it has the potential to transmit Dutch elm disease. The beetle was studied in six communities in 2009–2011 in Manitoba and Saskatchewan to learn about its biology in the Prairies. Baited sticky traps revealed that the adult flight period is from June until October, with a peak in late summer. Unbaited sticky traps and trap logs revealed that stressed Siberian elm is the preferred host. Although S. schevyrewi larvae overwintered successfully, 15% of the overwintering individuals emerged in the spring. The main impact of S. schevyrewi is expected to be the killing of stressed Siberian elms. Such trees should be removed to avoid population outbreaks that might result in attacks on healthy Siberian and American elms.

A genetic catalogue was generated from expressed sequence tags (ESTs) from the pathogenic filamentous fungus Ophiostoma novo-ulmi. Rather than full sequencing of the entire genome, fragments of each gene being actively expressed at a specific point in time were catalogued and annotated for identity and function. This catalogue represents a resource of considerable depth for the purposes of gene discovery, genetic regulation, protein expression, pathogenicity, and growth state studies. An online database was generated to serve as a powerful tool for downstream applications, facilitating and enhancing future research in all of these important areas of fungal biology. The ascomycetous fungus Ophiostoma novo-ulmi represents an excellent model organism for genetic experimentation. A diversity of physiological functions, including dimorphism, pathogenicity, melanin biosynthesis, and glycoprotein secretion at high levels mean that principles elucidated from this fungus are likely of broad application. Ophiostoma novo-ulmi has been identified as the causative agent of Dutch elm disease, which has become an economic and horticultural pandemic in North America. As a result, the mechanisms of host-pathogen interaction of this fungus are of particular interest. Initial attempts at disruption of pathogenicity, most commonly by disruption of single genes identified as potential pathogenicity factors, have met with little success. As our understanding of the complexity and co-ordination of proteins involved with host-pathogen interaction deepens, the discovery of a single dominant pathogenicity gene is becoming increasingly unlikely. As such, a broader genomics approach was employed to work towards identification of groups, or networks of genes that operate in a concerted manner, regulating pathogenicity or parasitic fitness. A low redundancy library was constructed from Ophiostoma nova-ulmi complementary DNA, producing a total of 4386 readable expressed sequence tags (ESTs) from 5760 clones. Of these, 2093 sequences matched with sequences found in public databases while 2293 represented orphan sequences. Of the sequences in the former group, 1761 sequences matched with known proteins while 332 sequences matched with hypothetical/predicted proteins. Sequences matching known proteins included 880 singletons, corresponding to 49.97 % of the ESTs in this category. Extrapolating this proportion to the sequences matching hypothetical proteins estimated the number of singletons in this category to be 166. Similarly, 1835 orphan sequences were estimated to contain 917 unique sequences. Singletons matching entries in public databases (n=880) were manually annotated into functional categories as established by the Munich Information Centre for Protein Sequences (MIPS). Metabolism (21%), Protein Synthesis (10%), Subcellular Localization (10%), Biogenesis of Cell Components (8%), and Transcription (8%) categories were the most highly represented.