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In the model dicotyledonous plant Arabidopsis thaliana, the basic helix-loop-helix (bHLH) transcription factor Phytochrome-Interacting Factor 4 (AtPIF4) plays a central role in regulating the ambient temperature-regulated hypocotyl growth response. Warm temperatures induce AtPIF4 transcription and the accumulated AtPIF4 promotes thermomorphogenesis by enhancing the expression of a group of growth-related genes. However, whether this thermo-induced growth response is universal, and more importantly, whether there is a conserved thermomorphogenetic mechanism shared in dicots is largely unknown. Here we show that higher ambient temperatures promote the hypocotyl growth in four other dicotyledonous plants, including Brassica rapa, Camelina sativa, Nicotiana benthamiana, and Medicago sativa. Moreover, all four species have orthologous genes of AtPIF4 in their genomes. Interestingly, the expression of at least one AtPIF4 ortholog in each species can be induced by elevated ambient temperatures. This study demonstrates that thermomorphogenesis is not limited to Arabidopsis and the thermal activation of PIF4 transcription may be a symbolic event in the thermomorphogenetic responses shared by a variety of dicotyledonous species.
Clutton, Caroline, "Transcriptional Activation of Phytochrome-Interacting Factor 4 is a Conserved Mechanism of Thermomorphogenesis in Dicotyledenous Plants" (2021). Honors Theses. 1868.
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