Genetic dissection of signaling processes regulating response to elevated ambient temperatures in Arabidopsis thaliana
Plant Genetics and Genomics
Final Report Abstract
This project aimed to identify novel regulators that mediate morphological plant responses to warm temperatures (termed thermomorphogenesis) and to characterize their function within the known framework of molecular regulators that centers around the transcription factor PIF4. Using a forward genetic approach, we previously have isolated mutants which are compromised in their ability to elongate hypocotyls in response to elevated temperatures. Identification of the genes that cause the altered phenotype resulted in two promising candidates: D6PK and SMAX1. While SMAX1 function in thermomorphogenesis has recently been published by another group, we were able to show that D6PK is required for temperature-induced auxin to translocate from cotyledons into the hypocotyl to induce cell elongation. In a second approach, we aimed to specifically identify transcription factors that contribute to thermomorphogenesis regulation using the available TRANSPLANTA collection which allows inducible overexpression of hundreds of transcription factor genes. Here, several promising candidate genes were identified that caused hypersensitive or reduced temperature responses. While characterization of their potential role in thermomrophogenesis is ongoing for several of the identified TFs, we focused specifically on a group of (b)HLH transcription factors, some of which have previously been implicated as regulators of cell elongation. For several members of this TF family, a tripartite level of antagonistic regulation has been implicated in response to several stimuli. This tri-antagonistic system involves the actual bHLH transcriptional regulators which can be repressed by binding to a HLH repressor. The repressor can be scavenged by binding of a secondary HLH repressor which thereby de-represses the inhibition of the actual transcriptional regulator. We were able to show that PIF4 function at warm ambient temperature can be modulated by PAR repressors and PRE secondary repressors and that loss of the respective genes affects thermomorphogenesis. Furthermore, PIF4 can bind to the promoter of its secondary repressor PRE1 which suggests a feed-forward regulation by which PIF4 can prevent its inhibition via PARs by inducing a secondary repressor (PREs) to scavenge the repressor (PARs).
Publications
- (2014) The DET1-COP1-HY5 pathway constitutes a multipurpose signaling module regulating plant photomorphogenesis and thermomorphogenesis. Cell Reports 9:1983-1989
Delker C, Sonntag L, Velikkakam James G, Janitza P, Ibañez C, Ziermann H, Peterson T, Denk K, Mull S, Ziegler J, Davis SJ, Schneeberger K, Quint M
(See online at https://doi.org/10.1016/j.celrep.2014.11.043) - (2015) Natural Variants of ELF3 Affect Thermomorphogenesis by Transcriptionally Modulating PIF4- Dependent Auxin Response Genes. BMC Plant Biology 15:197
Raschke A, Ibañez C, Ullrich KK, Anwer MU, Becker S, Glöckner A, Trenner J, Denk K, Saal B, Sun X, Ni M, Davis SJ, Delker C, Quint M
(See online at https://doi.org/10.1186/s12870-015-0566-6) - (2016) Molecular and genetic control of plant thermomorphogenesis. Nature Plants 2:15190
Quint M, Delker C, Franklin KA, Wigge PA, Halliday KJ, van Zanten M
(See online at https://doi.org/10.1038/nplants.2015.190) - (2018). Brassinosteroids dominate hormonal regulation of plant thermomorphogenesis via BZR1. Current Biology 28:303-310
Ibañez C, Delker C, Martinez C, Bürstenbinder K, Janitza P, Lippmann R, Ludwig W, Sun H, James GV, Klecker M, Grossjohann A, Schneeberger K, Prat S, Quint M
(See online at https://doi.org/10.1016/j.cub.2017.11.077) - (2019). A mobile auxin signal connects temperature sensing in cotyledons with growth responses in hypocotyls. Plant Physiology 180:757–766
Bellstaedt J, Trenner J, Lippmann R, Poeschl Y, Zhang X, Friml J, Quint M, Delker C
(See online at https://doi.org/10.1104/pp.18.01377) - (2019). Development of wild and cultivated plants under global warming conditions. Current Biology 29:R1326-R1338
Lippmann R, Babben S, Menger A, Delker C, Quint M
(See online at https://doi.org/10.1016/j.cub.2019.10.016) - (2020) Cut and paste - Temperature-enhanced cotyledon micrografting for Arabidopsis thaliana seedlings. Plant Methods 16:12
Bartusch K, Trenner J, Melnyk CW, Quint M
(See online at https://doi.org/10.1186/s13007-020-0562-1) - (2021) High and low temperature signalling and response. Journal of Experimental Botany 72:7339-7344
de Smet I, Quint M, van Zanten M
(See online at https://doi.org/10.1093/jxb/erab447) - (2021) On the evolution of plant thermomorphogenesis. Journal of Experimental Botany 72:7345–7358
Ludwig W, Hayes S, Trenner J, Delker C, Quint M
(See online at https://doi.org/10.1093/jxb/erab310) - (2022) High temperature perception in leaves promotes vascular regeneration and graft formation in distant tissues. Development 149:dev200079
Serivichyaswat PT, Bartusch K, Leso M, Musseau C, Iwase A, Chen Y, Sugimoto K, Quint M, Melnyk CW
(See online at https://doi.org/10.1242/dev.200079)
