Pto is a serine/threonine kinase that mediates resistance in tomato to strains of Pseudomonas syringae pv. tomato expressing the (a)virulence proteins AvrPto or AvrPtoB. DNA shuffling was used as a combinatorial in vitro genetic approach to dissect the functional regions of Pto. The Pto gene was shuffled with four of its paralogs from a resistant haplotype to create a library of recombinant products that was screened for interaction with AvrPto in yeast. All interacting clones and a representative sample of noninteracting clones were sequenced, and their ability to signal downstream was tested by the elicitation of a hypersensitive response in an AvrPto-dependent or -independent manner in planta. Eight candidate regions important for binding to AvrPto or for downstream signaling were identified by statistical correlations between individual amino acid positions and phenotype. A subset of the regions had previously been identified as important for recognition, confirming the validity of the shuffling approach. Three novel regions important for Pto function were validated by site-directed mutagenesis. Several chimeras and point mutants exhibited a differential interaction with (a)virulence proteins in the AvrPto and VirPphA family, demonstrating distinct binding requirements for different ligands. Additionally, the identification of chimeras that are both constitutively active as well as capable of binding AvrPto indicates that elicitation of downstream signaling does not involve a conformational change that precludes binding of AvrPto, as previously hypothesized. The correlations between phenotypes and variation generated by DNA shuffling paralleled natural variation observed between orthologs of Pto from Lycopersicon spp.

Social enterprises viewed as viable from societal perspectives are often regarded differently from traditional business perspectives. To examine this difference, we undertook two empirical studies of risk tolerance and legitimacy perceptions among observers of social enterprise and for-profit ventures. In Study 1, participants (n = 115) drawn randomly from Amazon’s Mechanical Turk, an online crowdsourcing marketplace for human intelligence tasks, examined two hypothetical cases and completed the risk tolerance scale of the Jackson Personality Inventory. Results show that social enterprises were seen as having lower industry legitimacy, especially by individuals with lower risk tolerance. Here, industry legitimacy mediated the effect of venture purpose on cognitive legitimacy. In Study 2, practicing entrepreneurs (n = 23) narratively interpreted Study 1 results from social enterprise and traditional business perspectives. Both studies demonstrate that social enterprise legitimacy evaluations vary based on risk tolerance and the type of legitimacy in question. Overall findings show that explicit observations of risk tolerance effects, and multidimensional conceptualizations of legitimacy, are important to accurate evaluations of social enterprises.

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