Honors Theses

Date of Award

Spring 4-30-2021

Document Type

Undergraduate Thesis



First Advisor

Yongjian Qiu

Second Advisor

Jason Hoeksema

Third Advisor

Josh Bloomekatz

Relational Format



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.

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

Available for download on Sunday, April 30, 2023