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Activation Tagging Identifies WRKY14 as a Repressor of Plant Thermomorphogenesis in Arabidopsis


Prof. Genji Qin published a paper in Molecular Plant with his collaborator.

Increases in recorded high temperatures around the world are causing plant thermomorphogenesis and decreasing crop productivity. PHYTOCHROME INTERACTING FACTOR 4 (PIF4) is a central positive factor in plant thermomorphogenesis. However, the mechanisms underlying thermomorphogenesis and the tight regulation of PIF4 remain to be clarified. Here, we identified ABNORMAL THERMOMORPHOGENESIS 1 (ABT1) as an important negative regulator of PIF4 and thermomorphogenesis. Overexpression of ABT1 in the activation tagging mutant abt1-D caused shorter hypocotyls and petioles under moderately high temperature (HT). ABT1 encodes WRKY14, which belongs to subgroup II of the WRKY transcription factors. Overexpression of ABT1/WRKY14 or its close homologs, including ABT2/WRKY35ABT3/WRKY65 and ABT4/WRKY69 in transgenic plants caused insensitivity to HT, while the quadruple mutant abt1 abt2 abt3 abt4 exhibited greater sensitivity to HT. ABTs were suppressed by HT and were expressed in hypocotyls, cotyledons, shoot apical meristems and leaves. We demonstrated that ABT1 interacted with TCP5, a known positive regulator of PIF4, and interrupted formation of the TCP5-PIF4 complex to repress PIF4 activity. Genetic analysis showed that ABT1 functioned antagonistically with TCP5, BZR1 and PIF4 in plant thermomorphogenesis. Taken together, our study identifies that ABT1/WRKY14 as a critical repressor of plant thermomorphogenesis and suggests that ABT1/WRKY14, TCP5 and PIF4 might form a sophisticated regulatory module to fine-tune PIF4 activity and temperature-dependent plant growth.

Original link: https://www.sciencedirect.com/science/article/pii/S1674205222003124.