Open Access

ARTICLE

AFP2 Coordinates the Activity of PIF7 for Thermomorphogenesis in Arabidopsis Seedlings

by Guoli Deng, Songbei Ying, Sasa Jing, Jun Zhou, Shiyan Lu, Ping Li^*

Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai, 200444, China

* Corresponding Author: Ping Li. Email:

Phyton-International Journal of Experimental Botany 2021, 90(4), 1089-1101. https://doi.org/10.32604/phyton.2021.016217

Received 18 February 2021; Accepted 09 March 2021; Issue published 27 April 2021

Abstract

Ambient temperature induces the hypocotyl elongation of seedling, called as thermomorphogenesis. It has been reported that the bHLH transcriptional factor PIF7 acts as the critical component to modulate plant thermomorphogenesis, but the underlying mechanism remains elusive. The phytohormone abscisic acid (ABA) suppresses the hypocotyl elongation under high temperature (HT) stress. As the ABI5 binding protein, AFP2 acts as the negative factor to control ABA signaling. In this study, we first identified AFP2 as the interaction protein of PIF7 in vitro and in vivo. Phenotype analysis revealed that overexpressing AFP2 reduced the hypocotyl elongation, while loss-of-function afp2 mutant showed longer hypocotyl under HT. Consistently, overexpressing AFP2 impaired the transactivation effect of PIF7 on auxin biosynthesis related genes YUC8 and IAA19, which possibly resulted into the shorter hypocotyl in the transgenic line overexpressing AFP2 or co-overexpressing AFP2 and PIF7. Thus, these data suggest that AFP2 suppressed PIF7 activity to suppress hypocotyl elongation. Furthermore, we found that HT gradually induced the degradation of AFP2 that possibly released the inhibitory effect of AFP2 on PIF7, thus induced hypocotyl elongation under HT. Taken together, our result reveals the novel function of AFP2 in coordinating thermomorphogenesis through sophistically modulating PIF7 activity.

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Keywords

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Supplementary Material

Supplementary Material File

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