The role of auxin in temperature regulated hypocotyl elongation

Estelle, Mark¹ 

[1] Univ. of California, San Diego, CA (United States)

关键词: auxin;    temperature;    plant growth;   

DOI  :  10.2172/1222223
RP-ID  :  DOEUCSD16007
PID  :  OSTI ID: 1222223

学科分类：生物科学（综合）

美国|英语

来源: SciTech Connect

【 摘 要 】

The major goal of this project was to determine how auxin mediates the response of Arabidopsis seedlings to increased ambient temperature. Previous studies have shown that the response is due, in part, to increased auxin biosynthesis via the IPA auxin biosynthetic pathway. This effect is related to increased transcription of genes that encode enzymes in this pathway. However, during the last year we have shown that transcription of key auxin regulated genes increases within minutes of a shift to elevated temperature. This response is probably to rapid to be explained by changes in the levels of auxin biosynthetic enzymes. Interestingly, we have recently discovered that temperature shift is associated with a rapid increase in the level of the auxin co-receptor TIR1. This change appears is the result of increased stability of the protein. At the same time, we have discovered that stability of TIR1 is dependent on the chaperone HSP9o and its co-chaperone SGT1. By using the specific HSP90 inhibitor GDA, we show that HSP90 is required for the temperature dependent change in TIR1 levels. We have also shown that HSP90 and SGT1 interact directly with TIR1. Our results also lead us to propose a new model in which the plant responds rapidly to changes in ambient temperature by directly regulating the TIR1/AFB receptor system, thus modulating the auxin signaling pathway.