Molecular Biology Laboratory, Department of Biotechnology, Agricultural University of Athens, Iera Odos 75, Athens, 118 55, Greece.
Department of Chemical Biology, Faculty of Science, Palacký University, Šlechtitelů 27, Olomouc, CZ-78371, Czech Republic.
New Phytol. 2021 Sep;231(5):1814-1831. doi: 10.1111/nph.17528. Epub 2021 Jul 6.
Auxin homeostasis and signaling affect a broad range of developmental processes in plants. The interplay between HSP90 and auxin signaling is channeled through the chaperoning capacity of the HSP90 on the TIR1 auxin receptor. The sophisticated buffering capacity of the HSP90 system through the interaction with diverse signaling protein components drastically shapes genetic circuitries regulating various developmental aspects. However, the elegant networking capacity of HSP90 in the global regulation of auxin response and homeostasis has not been appreciated. Arabidopsis hsp90 mutants were screened for gravity response. Phenotypic analysis of root meristems and cotyledon veins was performed. PIN1 localization in hsp90 mutants was determined. Our results showed that HSP90 affected the asymmetrical distribution of PIN1 in plasma membranes and influenced its expression in prompt cell niches. Depletion of HSP90 distorted polar distribution of auxin, as the acropetal auxin transport was highly affected, leading to impaired root gravitropism and lateral root formation. The essential role of the HSP90 in auxin homeostasis was profoundly evident from early development, as HSP90 depletion affected embryo development and the pattern formation of veins in cotyledons. Our data suggest that the HSP90-mediated distribution of PIN1 modulates auxin distribution and thereby auxin signaling to properly promote plant development.
生长素稳态和信号转导影响植物广泛的发育过程。HSP90 和生长素信号之间的相互作用是通过 HSP90 对 TIR1 生长素受体的伴侣能力来实现的。HSP90 系统通过与多种信号蛋白成分的相互作用，具有复杂的缓冲能力，极大地影响了调节各种发育方面的遗传电路。然而，HSP90 在生长素反应和稳态的全局调控中的优雅网络能力尚未得到充分认识。筛选拟南芥 hsp90 突变体以检测其对重力的反应。对根分生组织和子叶叶脉进行表型分析。测定 hsp90 突变体中 PIN1 的定位。结果表明，HSP90 影响质膜中 PIN1 的不对称分布，并影响其在快速细胞龛中的表达。HSP90 的耗竭使生长素的极性分布发生扭曲，因为向顶的生长素运输受到严重影响，导致根向地性和侧根形成受损。从早期发育来看，HSP90 在生长素稳态中的重要作用非常明显，因为 HSP90 的耗竭影响了胚胎发育和子叶叶脉的模式形成。我们的数据表明，HSP90 介导的 PIN1 分布调节生长素分布，从而调节生长素信号，以正确促进植物发育。
