Grand Challenge: Viewing Transporter Function in a Pointillist Landscape

Membrane transport proteins play vital roles in plant development, signaling, environmental interactions, and biosynthesis. Transporter activity has been traditionally studied either at the level of whole plant physiology or in single cells and artificial systems. The tools available for these studies have expanded dramatically over the past decade. Genomic, transcriptomic, proteomic, metabolomic, and associomic/interactomic methodologies (Lalonde, et al., 2010) have produced large datasets that can be probed with bioinformatic tools to visualize transport networks within whole plants, organs, and tissues. Large collections of characterized mutants and mapped natural variation collections provide tools for rapid turnaround of forward genetic screens and reverse genetic assessment of gene function. Improved systems for heterologous expression of plant membrane proteins and an expanding set of defined pharmacological inhibitors provide the capability to rapidly evaluate the function of transporters in relative isolation and to identify proteins that regulate their activity. Live imaging of functional fluorescently tagged proteins has revolutionized plant cell biology and accelerated the understanding of membrane protein trafficking mechanisms (see Gilroy, 2011). Finally, improved crystallization and structural resolution technologies have increased the number of membrane protein structures available for threading of plant amino acid sequences to create testable models for experimental design. Frontiers in Plant Traffic and Transport is expected to serve as a forum for research utilizing all of these approaches and to function as a specialized journal for the presentation of functional evaluations of plant membrane transporters and the mechanisms by which they are trafficked and transported. The grand challenge for work in the plant transport field is the integration of multiple information streams into models and understandings that fully realize the complexity of plant transport systems. There is hope that well-crafted transformations of datasets will reveal structured networks of processes in a manner similar to the visual assembly that occurs when viewing a pointillist painting. Using filters derived from evolutionary concepts or pattern-recognition algorithms, such bioinformatic exercises have produced important results. However, outputs are generally useful only when all of the available datasets were generated under identical conditions and validated to the same standards (Baxter et al., 2010). It is hoped that the creation of this specialty journal will aid the process of standardization of methodologies and provide a ready resource for investigators desiring to select the best systems for validation of datasets pertinent to their own analyses of plant transport function. It is hoped that a number of realities and experimental limitations encountered in plant transport research will be openly presented and discussed in this journal. Apart from the difficulty inherent in exploration of complex natural systems, there are specific challenges and practices that the journal seeks to overcome: