To flower or not to flower, a temperature-sensitive decision: Characterization of flowering responses at high ambient temperature in Arabidopsis thaliana

To maximize fitness, plants use environmental cues to optimize growth processes. One of the processes under strong environmental regulation is flowering. Multiple environmental factors influence flowering, including temperature. Both a continuously increased ambient temperature as well as temporary increases in temperature affect flowering time. Like most plant species, a majority of Arabidopsis accessions shows accelerated flowering at high ambient temperatures. We identified a floral pathway integrator gene to be involved in floral signal integration at warm temperatures. Furthermore several genes are found to be important for the floral response to both continuous and temporary high ambient temperature in LDs.A huge variation in thermosensory flowering responses, including delay in flowering at warmer temperatures, was observed in natural occurring accessions of Arabidopsis thaliana. A Genome-Wide Association study was followed to identify the genetic variation underlying this phenotypic variation. This led to the identification of several candidate genes. Via genome-wide transcriptome analyses on plants exposed to 24h of increased temperatures we, once more, identified the same floral pathway integrator gene as an important integrator in temperature-mediated flowering.
Control of flowering time is of great importance to the plant breeding industry. On the one hand, early flowering of plants might considerably speed up the production process and reduce costs, on the other hand shortening of the growth time can result in yield loss. Average growing season temperatures in the next century will exceed the warmest temperatures from the past century. Detailed knowledge of mechanisms underlying the regulation of flowering time by ambient temperature is essential to be able to breed for crops with improved responses to a warmer environment. In many crops, both seed and vegetable crops, a prolonged vegetative phase at increased ambient temperature is a desired trait. The information found in this study has great potential value to the breeding industry.