• Energy Research

SummaryControlled expression of transgenes in plants is key to the characterization of gene function and the regulated manipulation of growth and development. The alc gene‐expression system, derived from the filamentous fungus Aspergillus nidulans, has previously been used successfully in both tobacco and potato, and has potential for use in agriculture. Its value to fundamental research is largely dependent on its utility in Arabidopsis thaliana. We have undertaken a detailed function analysis of the alc regulon in A. thaliana. By linking the alcA promoter to β‐glucuronidase (GUS), luciferase (LUC) and green fluorescent protein (GFP) genes, we demonstrate that alcR‐mediated expression occurs throughout the plant in a highly responsive manner. Induction occurs within one hour and is dose‐dependent, with negligible activity in the absence of the exogenous inducer for soil‐grown plants. Direct application of ethanol or exposure of whole plants to ethanol vapour are equally effective means of induction. Maximal expression using soil‐grown plants occurred after 5 days of induction. In the majority of transgenics, expression is tightly regulated and reversible. We describe optimal strategies for utilizing the alc system in A. thaliana.

Summary Information about the incidence and magnitude of local adaptation can help to predict the response of natural populations to a changing environment, and should be of particular interest in arctic and alpine environments where the effects of climate change are expected to be severe. To quantify adaptive differentiation in the arctic‐alpine perennial herb Arabis alpina, we conducted reciprocal transplant experiments for 3 yr between Spanish and Scandinavian populations. At the sites of one Spanish and one Scandinavian population, we planted seedlings representing two Spanish and four Scandinavian populations, and recorded survival, flowering propensity and fecundity. The experiment was replicated in two subsequent years. The results demonstrate strong adaptive differentiation between A. alpina populations from the two regions. At the field site in Spain, survival and fruit production of Spanish populations were higher than those of Scandinavian populations, while the opposite was true at the site in Scandinavia, and these differences were consistent across years. By comparison, fitness varied little among populations from the same region. The results suggest that the magnitude and geographical scale of local adaptation need to be considered in predictions of the effects of global change on the dynamics of arctic and alpine plant populations.

Summary A group of MADS transcription factors (TFs) are believed to control temperature‐mediated bud dormancy. These TFs, called DORMANCY‐ASSOCIATED MADS‐BOX (DAM), are encoded by genes similar to SHORT VEGETATIVE PHASE (SVP) from Arabidopsis. MADS proteins form transcriptional complexes whose combinatory composition defines their molecular function. However, how MADS multimeric complexes control the dormancy cycle in trees is unclear. Apple MdDAM and other dormancy‐related MADS proteins form complexes with MdSVPa, which is essential for the ability of transcriptional complexes to bind to DNA. Sequential DNA‐affinity purification sequencing (seq‐DAP‐seq) was performed to identify the genome‐wide binding sites of apple MADS TF complexes. Target genes associated with the binding sites were identified by combining seq‐DAP‐seq data with transcriptomics datasets obtained using a glucocorticoid receptor fusion system, and RNA‐seq data related to apple dormancy. We describe a gene regulatory network (GRN) formed by MdSVPa‐containing complexes, which regulate the dormancy cycle in response to environmental cues and hormonal signaling pathways. Additionally, novel molecular evidence regarding the evolutionary functional segregation between DAM and SVP proteins in the Rosaceae is presented. MdSVPa sequentially forms complexes with the MADS TFs that predominate at each dormancy phase, altering its DNA‐binding specificity and, therefore, the transcriptional regulation of its target genes.