50 years of Arabidopsis research: Highlights and future directions

The year 2014 marked the 25th International Conference on Arabidopsis Research. In the 50 yr since the first International Conference on Arabidopsis Research, held in 1965 in Göttingen, Germany, > 54 000 papers that mention Arabidopsis thaliana in the title, abstract or keywords have been published. We present herein a citational network analysis of these papers, and touch on some of the important discoveries in plant biology that have been made in this powerful model system, and highlight how these discoveries have then had an impact in crop species. We also look to the future, highlighting some outstanding questions that can be readily addressed in Arabidopsis. Topics that are discussed include Arabidopsis reverse genetic resources, stock centers, databases and online tools, cell biology, development, hormones, plant immunity, signaling in response to abiotic stress, transporters, biosynthesis of cells walls and macromolecules such as starch and lipids, epigenetics and epigenomics, genome-wide association studies and natural variation, gene regulatory networks, modeling and systems biology, and synthetic biology

Ethylene-induced hyponastic growth in Arabidopsis thaliana is controlled by ERECTA

Plants can respond quickly and profoundly to detrimental changes in their environment. For example, Arabidopsis thaliana can induce an upward leaf movement response through differential petiole growth (hyponastic growth) to outgrow complete submergence. This response is induced by accumulation of the phytohormone ethylene in the plant. Currently, only limited information is available on how this response is molecularly controlled. In this study, we utilized quantitative trait loci (QTL) analysis of natural genetic variation among Arabidopsis accessions to isolate novel factors controlling constitutive petiole angles and ethylene-induced hyponastic growth. Analysis of mutants in various backgrounds and complementation analysis of naturally occurring mutant accessions provided evidence that the leucin-rich repeat receptor-like Ser/Thr kinase gene, ERECTA, controls ethylene-induced hyponastic growth. Moreover, ERECTA controls leaf positioning in the absence of ethylene treatment. Our data demonstrate that this is not due to altered ethylene production or sensitivit

Ethylene-induced hyponastic growth in Arabidopsis thaliana is controlled by ERECTA

Plants can respond quickly and profoundly to detrimental changes in their environment. For example, Arabidopsis thaliana can induce an upward leaf movement response through differential petiole growth (hyponastic growth) to outgrow complete submergence. This response is induced by accumulation of the phytohormone ethylene in the plant. Currently, only limited information is available on how this response is molecularly controlled. In this study, we utilized quantitative trait loci (QTL) analysis of natural genetic variation among Arabidopsis accessions to isolate novel factors controlling constitutive petiole angles and ethylene-induced hyponastic growth. Analysis of mutants in various backgrounds and complementation analysis of naturally occurring mutant accessions provided evidence that the leucin-rich repeat receptor-like Ser/Thr kinase gene, ERECTA, controls ethylene-induced hyponastic growth. Moreover, ERECTA controls leaf positioning in the absence of ethylene treatment. Our data demonstrate that this is not due to altered ethylene production or sensitivit

Identification of Consensus Regions Associated with Shoot Biomass Production in the Medicago

International audienceIdentification of common genome regions influencing biomass production in multiple Medicago populations can establish focal points for implementing future marker-assisted breeding approaches to improve alfalfa (M. sativa L.) forage yield and facilitate identification of candidate genes. The goal of this study was to identify consensus regions associated with biomass production and candidate genes within the context of the M. truncatula Gaertn. genome, based on previous reports of 83 biomass-affiliated markers and 30 quantitative trait loci (QTL) detected among one M. truncatula and four M. sativa biparental and association mapping populations. The genome positions for 68 markers and all 30 biomass QTL were determined. Ten consensus regions associated with Medicago forage yield in two or more populations were identified. The level of resolution for these regions, however, was not sufficient to clearly identify potential causal candidate genes. Consequently, a targeted set of 208 loci influencing Arabidopsis growth and development were surveyed for their positions in the Medicago genome to identify those which colocalized with biomass markers and QTL intervals. Among 233 homologous genes identified, 51 were located within consensus biomass regions. Potential genes affecting Medicago forage yield variation included those affiliated with phytohormone biosynthesis, transport, and signaling; light responsive developmental phase transitions; and microRNA-mediated regulation of gene expression. These outcomes provide insight into genetic factors that researchers may wish to target for future validation experiments, and for designing marker-assisted breeding strategies to improve alfalfa productivity

Tunable diffusive lateral inhibition in chemical cells

The Belousov-Zhabotinsky (BZ) reaction has become the prototype of nonlinear chemical dynamics. Microfluidic techniques provide a convenient method for emulsifying BZ solutions into monodispersed drops with diameters of tens to hundreds of microns, providing a unique system in which reaction-diffusion theory can be quantitatively tested. In this work, we investigate monolayers of microfluidically generated BZ drops confined in close-packed two-dimensional (2D) arrays through experiments and finite element simulations. We describe the transition from oscillatory to stationary chemical states with increasing coupling strength, controlled by independently varying the reaction chemistry within a drop and diffusive flux between drops. For stationary drops, we studied how the ratio of stationary oxidized to stationary reduced drops varies with coupling strength. In addition, using simulation, we quantified the chemical heterogeneity sufficient to induce mixed stationary and oscillatory patterns