Cytokinins Secreted by Agrobacterium Promote Transformation by Repressing a Plant Myb Transcription Factor

Agrobacterium-mediated transformation is the most widely used technique for generating transgenic plants. However, many crops remain recalcitrant. We found that an Arabidopsis myb family transcription factor (MTF1) inhibited plant transformation susceptibility. Mutating MTF1 increased attachment of several Agrobacterium strains to roots and increased both stable and transient transformation in both susceptible and transformation-resistant Arabidopsis ecotypes. Cytokinins from Agrobacterium tumefaciens decreased the expression of MTF1 through activation of the cytokinin response regulator ARR3. Mutating AHK3 and AHK4, genes that encode cytokinin-responsive kinases, increased the expression of MTF1 and impaired plant transformation. Mutant mtf1 plants also had increased expression of AT14A, which encodes a putative transmembrane receptor for cell adhesion molecules. Plants overexpressing AT14A exhibited increased susceptibility to transformation, whereas at14a mutant plants exhibited decreased attachment of bacteria to roots and decreased transformation, suggesting that AT14A may serve as an anchor point for Agrobacteria. Thus, by promoting bacterial attachment and transformation of resistant plants and increasing such processes in susceptible plants, treating roots with cytokinins may help engineer crops with improved features or yield

Identification of Arabidopsis rat Mutants

Limited knowledge currently exists regarding the roles of plant genes and proteins in the Agrobacterium tumefaciens-mediated transformation process. To understand the host contribution to transformation, we carried out root-based transformation assays to identify Arabidopsis mutants that are resistant to Agrobacterium transformation (rat mutants). To date, we have identified 126 rat mutants by screening libraries of T-DNA insertion mutants and by using various “reverse genetic” approaches. These mutants disrupt expression of genes of numerous categories, including chromatin structural and remodeling genes, and genes encoding proteins implicated in nuclear targeting, cell wall structure and metabolism, cytoskeleton structure and function, and signal transduction. Here, we present an update on the identification and characterization of these rat mutants

The global uprising of labour?: The Korean labour movement and neoliberal social corporatism

The role of organized labour as expression of dissent or social resistance to neoliberal economic globalization has attracted increasing scholarly interest. Several writers have argued that we are witnessing the emergence of a 'global uprising of labour'. In particular, reference is made to the labour movements of the industrializing semiperiphery, such as South Korea, South Africa, and Brazil, which are argued to show a way forward for the labour movements of the North. Such analysis as above, however, focuses on only one aspect of labour movements at the expense of their larger historical context and position within the capitalist world system. By privileging the strictly 'global' level of analysis, it ignores a key transformation in the nature of national state-society configurations in the semiperiphery, i.e. the general trend towards both democratization and neoliberal restructuring. Through examining the case of South Korea, I argue that the transition from developmental authoritarianism to neoliberal democracy has dramatically narrowed the terrain from which militant unionism might be expected to emerge. Since the 1980s, the Korean labour movement has undergone a transformation from a militant and almost revolutionary movement, to being co-opted, albeit imperfectly, into the new capitalist democracy. Thus, the threat of neoliberal restructuring has led not to resistance but to labour to seeking a role as responsible partner to government and business in pseudo-social corporatism forums, despite the fact the striking thing about Korean industrial relations is the absolute absence of prerequisites for such a system of social agreement politics. This co-optation reflects general political conditions in the semiperiphery, where simultaneous processes of democratization and neoliberal restructuring have made the assumption of unified resistance to globalization more problematic