Study of bHLH transcription factors in light signaling

In shade-intolerant plants such as Arabidopsis, a reduction in the red/far-red (R/FR) ratio, indicative of competition from other plants, triggers a suite of responses known as the shade avoidance syndrome (SAS). We are interested in HFR1, PIF4 and PIF5, bHLH transcription factors involved in the shade avoidance response. We were able to show that HFR1 interacts with PIF4 and PIF5 and limits their capacity to induce the expression of shade marker genes and to promote elongation growth.