Environmental stress and flowering time: the photoperiodic connection

Abstract

Plants maximize their chances to survive adversities by reprogramming their development according to environmental conditions. Adaptive variations in the timing to flowering reflect the need for plants to set seeds under the most favorable conditions. A complex network of genetic pathways allows plants to detect and integrate external (e.g., photoperiod and temperature) and/or internal (e.g., age) information to initiate the floral transition. Furthermore different types of environmental stresses play an important role in the floral transition. The emerging picture is that stress conditions often affect flowering through modulation of the photoperiodic pathway. In this review we will discuss different modes of cross talk between stress signaling and photoperiodic flowering, highlighting the central role of the florigen genes in this process.

Keywords: Florigen; drought escape; photoperiodic flowering; plant adaptive development; plant stress response.

Figure 1. Real-time qPCR of CO (A) or BFT (B) transcripts in 3 wk-old wild-type (Col-0), aba1-6 or gi-2 seedlings. Plants were subjected to normal watering (black lines) or reduced watering (gray lines) regimes and harvested at the indicated time points in coincidence with the light phase (open bar) or in the dark (black bar) during a SDs to LDs shift. At each time point, values represent fold change variations of CO or BFT transcript levels relatively to Col-0 under NW. ACT2 expression was used for normalization; error bars represent SD of 2 technical replicates. A representative experiment of 2 biological replicates is shown.