Just how many things can we really use Arabidopsis thaliana as a ‘model’ for? Certainly our favourite weed has an historic advantage for genomic research. As the first plant genome to be fully sequenced, it has had a long head start for all sorts of ‘omics databases and projects. The A. thaliana databases have proved useful for researchers working on other plant species too; even today Arabidopsis genomic sequences are used to fish un-annotated genomes for genes and motifs. A recent paper questions how appropriate it is to transfer in vivo Arabidopsis research on xylem and water flow to woody plant species. Yes, how useful is weedy (in all senses of the word), tiny A. thaliana to understand massive woody trees? The answer? It’s not perfect, but it’s OK.
Tixier et al. (JXB, doi:10.1093/jxb/ert087, Open Access) carried out a series of experiments to test A. thaliana’s value as a model for wood development. It turns out wildtype Arabidopsis is a good xylem hydraulic model, with tissue structure and vessel dimensions that are reliably representative of larger woody plants. To quote Tixier et al., “A. thaliana can be used to measure specific conductivity and cavitation resistance in an accurate and reliable approach,” and far more conveniently than trying to use an 8 metre tall tree to do it. However, the model plant is not appropriate for some xylem parameters, such as end-wall sensitivity. A. thaliana xylem also responded differently to abnormal environmental conditions and cell wall structure manipulation.
As an aside, Wendrich and Weijers present another system for which A. thaliana is an appropriate model in this month’s Tansley review in New Phytologist (doi: 10.1111/nph.12267). They describe current understanding of morphogenesis in the early A. thaliana embryo, and identify five key questions that still remain to be answered.