Cell wall degrading enzymes and interaction between Trichoderma Aggressivum and Agaricus Bisporus

Agaricus bisporus is the most commonly cultivated mushroom in North America and has a great economic value. Green mould is a serious disease of A. bisporus and causes major reductions in mushroom crop production. The causative agent of green mould disease in North America was identified as Trichoderma aggressivum f. aggressivum. Variations in the disease resistance have been shown in the different commercial mushroom strains. The purpose of this study is to continue investigations of the interactions between T. aggressivum and A. bisporus during the development of green mould disease. The main focus of the research was to study the roles of cell wall degrading enzymes in green mould disease resistance and pathogenesis. First, we tried to isolate and sequence the N-acetylglucosaminidase from A. bisporus to understand the defensive mechanism of mushroom against the disease. However, the lack of genomic and proteomic information of A. bisporus limited our efforts. Next, T. aggressivum cell wall degrading enzymes that are thought to attack Agaricus and mediate the disease development were examined. The three cell wall degrading enzymes genes, encoding endochitinase (ech42), glucanase (fJ-1,3 glucanase) and protease (prb 1), were isolated and sequenced from T. aggressivum f. aggressivum. The sequence data showed significant homology with the corresponding genes from other fungi including Trichoderma species. The transcription levels of the three T. aggressivum cell wall degrading enzymes were studied during the in vitro co-cultivation with A. bisporus using R T -qPCR. The transcription levels of the three genes were significantly upregulated compared to the solitary culture levels but were upregulated to a lesser extent in co-cultivation with a resistant strain of A. bisporus than with a sensitive strain. An Agrobacterium tumefaciens transformation system was developed for T. aggressivum and was used to transform three silencing plasmids to construct three new T. aggressivum phenotypes, each with a silenced cell wall degrading enzyme. The silencing efficiency was determined by RT-qPCR during the individual in vitro cocultivation of each of the new phenotypes with A. bisporus. The results showed that the expression of the three enzymes was significantly decreased during the in vitro cocultivation when compared with the wild type. The phenotypes were co-cultivated with A. bisporus on compost with monitoring the green mould disease progression. The data indicated that prbi and ech42 genes is more important in disease progression than the p- 1,3 glucanase gene. Finally, the present study emphasises the role of the three cell wall degrading enzymes in green mould disease infection and may provide a promising tool for disease management.

Everything that rises must converge: a neo-Marxist analysis of Canadian business-government relations

The following thesis presents an analysis of business-government relations within a neo-Marxist framework. Specifically, the discussion encompasses how the business interest group. the Business Council on National Issues, maintains consensus and unity amongst its monopoly capital members. Furthermore. the study elaborates on the process through which the group's interests are acknowledged and legitimized by the state under the "public interest" f8fue. Most of the literature pertaining to business-government relations within the context of interactions between business interest groups and the state, and such specific branches of the state as the government and/or the civil service. emphasize a liberal-pluralist perspective. Essentially, these writings serve to reflect and legitimate the current slatus quo. Marxist discourses on the subject, while attempting to transcend the liberal-pluralist framework. nevertheless suffer from either economic determinism .. ie., stressing the state's accumulation function but not its legitimation function or historical specificity. A cogent and comprehensive neo-Marxist analysis of business-government relations must discuss both the accumulation and legitimation functions of the state. The process by which the concerns of a particular business interest group become part of the state's policy agenda and subsequently are formulated and implemented into policies which legitimate its dominance is also studied. This inquiry is significant given the liberal-pluralist assumptions of a neutral state and that all interest groups compete "on a level playing field". The author's neo-Marxist paradigm rejects both of these assumptions. Building on concepts from nea-Marxist instrumentalism. structuralism. state monopoly capitalism, and forms and functions of the state perspectives. the author proposes that policies which legitimize the interests of the monopoly capital fraction cannot. be discerned only from the state's activities. per StJ. Clearly, if the liberal-pluralist 3 contention of multiple and conflicting interest groups, including those within the capitalist class, is taken at face value, M interest group such as the Business Council on National Issues (BCND, must somehow maintain. internal consensus Md unity amongst its members. Internal consensus amongst its members ensures that the state can better acknowledge and articulate its concerns into policies that maintain hegemonic dominance of the monopoly capital fraction under the "public interest" fllf.JJdq. The author contends that the BCNI focuses most of its interactions on the upper echelons of the civil service since it is this branch of the state which is most responsible for policy formulation and implementation. The author's paradigm is applied within the context of extensively analyzing newspaper coverage. BCN! publications, and other published sources, as well as a personal interview with an executive administrative member of the BeNI. The discussion focuses on how agreement and unity amongst the various interests of the monopoly capital fraction are maintained through the business organization, its policy scope, and finally its interactions with the state. The analysis suggests that while the civil service is an important player in expressing the interests of the BCNI's membership through policies which ostensibly also reflect the "public interest", it is not the only strategic target for the BCNI's interactions with the state. The author's research also highlights the importance of government officials at the Cabinet level and Cabinet Committees. Senior elected officials from the Federal government are also significant in avoiding intergovernmental or interprovincial conflict in implementing policies that legitimize hegemonic dominance of the monopoly capital fraction over other fractions and classes.