From bench to bountiful harvests : a road map for the next decade of Arabidopsis research

In the face of an increasing world population and climate instability, the demands for food and fuel will continue to rise. Plant science will be crucial to help meet these exponentially increasing requirements for food and fuel supplies. Fundamental plant research will play a major role in providing key advances in our understanding of basic plant processes that can then flow into practical advances through knowledge sharing and collaborations. The model plant Arabidopsis thaliana has played a major role in our understanding of plant biology, and the Arabidopsis community has developed many tools and resources to continue building on this knowledge. Drawing from previous experience of internationally coordinated projects, The international Arabidopsis community, represented by the Multinational Arabidopsis Steering Committee (MASC), has drawn up a road map for the next decade of Arabidopsis research to inform scientists and decision makers on the future foci of Arabidopsis research within the wider plant science landscape. This article provides a summary of the MASC road map

Cytokinin and auxin intersection in root meristems

Cytokinin promotes cell differentiation in plant roots by repressing auxin transport and responses at the meristem boundary

Auxin Action in a Cell-Free System

The plant hormone auxin regulates diverse aspects of plant growth and development [1]. Despite its importance, the mechanisms of auxin action remain poorly understood. In particular, the identities of the auxin receptor and other signaling proteins are unknown. Recent studies have shown that auxin acts by promoting the degradation of a family of transcriptional regulators called the Aux/IAA proteins 2, 3 and 4. These proteins interact with another large family of plant-specific transcription factors called Auxin Response Factors (ARF) and negatively regulate their activity [5]. Auxin stimulates Aux/IAA degradation by promoting the interaction between a ubiquitin protein ligase (E3) called SCFTIR1 and the Aux/IAA protein [2]. In this report, we demonstrate that auxin promotes the interaction between the Aux/IAA proteins and SCFTIR1 in a soluble extract free of membranes, indicating that this auxin response is mediated by a soluble receptor. In addition, we show that the response is not dependent on protein phosphorylation or dephosphorylation but rather is prevented by an inhibitor of peptidyl-prolyl isomerases

Auxin-sensitive Aux/IAA proteins mediate drought tolerance in Arabidopsis by regulating glucosinolate levels.

A detailed understanding of abiotic stress tolerance in plants is essential to provide food security in the face of increasingly harsh climatic conditions. Glucosinolates (GLSs) are secondary metabolites found in the Brassicaceae that protect plants from herbivory and pathogen attack. Here we report that in Arabidopsis, aliphatic GLS levels are regulated by the auxin-sensitive Aux/IAA repressors IAA5, IAA6, and IAA19. These proteins act in a transcriptional cascade that maintains expression of GLS levels when plants are exposed to drought conditions. Loss of IAA5/6/19 results in reduced GLS levels and decreased drought tolerance. Further, we show that this phenotype is associated with a defect in stomatal regulation. Application of GLS to the iaa5,6,19 mutants restores stomatal regulation and normal drought tolerance. GLS action is dependent on the receptor kinase GHR1, suggesting that GLS may signal via reactive oxygen species. These results provide a novel connection between auxin signaling, GLS levels and drought response

Task-Shifting: Can Community Health Workers Be Part of the Solution to an Inactive Nation?

Background: In low-to-middle income countries (LMICs), there is a growing burden of non-communicable diseases (NCDs) placing strain on the facilities and human resources of healthcare systems. Prevention strategies that include lifestyle behavior counseling have become increasingly important. We propose a potential solution to the growing burden of NCDs through an expansion of the role for community health workers (CHWs) in prescribing and promoting physical activity in public health settings. This discussion paper provides a theoretical model for task-shifting of assessment, screening, counseling, and prescription of physical activity to CHWs. Five proposed tasks are presented within a larger model of service delivery and provide a platform for a structured, standardized, physical activity prevention strategy aimed at NCDs using CHWs as an integral part of reducing the burden of NCDs in LMICs. However, for effective implementation as part of national NCD plans, it is essential that CHWs received standardized, ongoing training and supervision on physical activity and other lifestyle behaviors to optimally impact community health in low resource settings

The axr1 Mutation of Arabidopsis is Expressed 10 Booth Roots and Shoots

In order to identify genes involved in auxin action we have isolated a number of mutants of Arabidopsis thaliana which are resistant co exogenous application of either indole-3-acetic acid or 2, 4-dichlorophenoxyacecic acid. One of the genes identified in chis way is the Axr1 gene. Recessive mutations in this gene confer resistance co auxin as well as a number of morphological defects. In this report we describe the isolation of at least two new axr1 alleles. In addition, we show that the axr1 mutation affects gravitropic growth of the root, auxin-induced ethylene biosynthesis and growth in tissue culture. Our results indicate chat the axr1 mutation is expressed in most tissues of the plant