Integrative phenotyping approaches to unmask the Phyb-PIF4 pathway in Arabidopsis thaliana reproductive organs at high ambient temperatures

Abstract

Abstract Background The increasing ambient temperature significantly impacts plant growth, development, and reproduction. Uncovering the temperature-regulating mechanisms in plants is of high importance, not only for boosting our plant biology knowledge but also for assisting plant breeders in improving plant resilience to these stress conditions. Numerous studies on the molecular mechanisms by which plants regulate temperature responses revealed that plants employ distinct transcription factors to regulate thermomorphogenesis specific to each tissue type. A significant discovery in this field was the identification of PHYTOCHROME-INTERACTING FACTORs (PIFs) as key regulators of thermomorphogenesis during vegetative growth. PIF4, a regulator of auxin-mediated signaling pathways, is crucial in controlling high-temperature responses. Results In this study, we screened the temperature responses of the wild type and several PhyB-PIF4 pathway Arabidopsis mutant lines in combined and integrative phenotyping platforms for root in soil, shoot, inflorescence, and seed. We demonstrated that high ambient temperature differentially impacts vegetative and reproductive organs through this pathway. Suppression of the PhyB-PIF4 components mimics the response to a high ambient temperature in wild-type plants. We also identified correlative responses to high ambient temperature between shoot and root tissues. This integrative and automated phenotyping was complemented by monitoring the changes in transcript levels in reproductive organs. Transcriptomic profiling of the pistils from plants grown under high ambient temperature identified key elements that may provide clues to the molecular mechanisms behind temperature-induced reduced fertilization rate, such as a downregulation of auxin metabolism, upregulation of genes involved auxin signalling, miRNA156 and miRN160 pathways, pollen tube attractants. Conclusions Thermomorphogenesis is uniquely controlled in the different plant tissues at different developmental stages. We have identified key elements that may help to determine the response to high ambient temperatures during reproduction processes.

Plant phenotyping relevance

複数器官を対象とする統合・自動フェノタイピングプラットフォームを用いた大規模な表現型取得が研究の主要な構成要素であり、単なるルーチン測定を超える実質的な方法適用と判断する。

Code and data availability

The preprint describes integrative phenotyping (PlantScreen, Boxeed, rhizotrons, microscopy) and RNA-seq, but no public phenotype/trait dataset, image repository, or author analysis code/workflow is deposited or linked. The only deposit mentioned is the RNA-seq BioProject (PRJNA1091589), which is molecular omics data,

No evidence-backed public reproduction asset is currently recorded.