Summary: Cold stress is one of the major environmental factors that limit growth and yield of plants. However, it is still not fully understood how plants account for daily temperature fluctuations, nor how these temperature changes are integrated with other regulatory systems such as the circadian clock. We demonstrate that REVEILLE2 undergoes alternative splicing after chilling that increases accumulation of a transcript isoform encoding a MYB‐like transcription factor. We explore the biological function of REVEILLE2 in Arabidopsis thaliana using a combination of molecular genetics, transcriptomics, and physiology. Disruption of REVEILLE2 alternative splicing alters regulatory gene expression, impairs circadian timing, and improves photosynthetic capacity. Changes in nuclear gene expression are particularly apparent in the initial hours following chilling, with chloroplast gene expression subsequently upregulated. The response of REVEILLE2 to chilling extends our understanding of plants immediate response to cooling. We propose that the circadian component REVEILLE2 restricts plants responses to nocturnal reductions in temperature, thereby enabling appropriate responses to daily environmental changes.

Summary: Cold stress is one of the major environmental factors that limit growth and yield of plants. However, it is still not fully understood how plants account for daily temperature fluctuations, nor how these temperature changes are integrated with other regulatory systems such as the circadian clock. We demonstrate that REVEILLE2, a MYB-like transcription factor, exhibits a cold-induced alternative splicing switch from a non-translatable isoform at ambient temperature to a translatable isoform upon cold exposure. We explore the biological function of REVEILLE2 using a combination of molecular genetics, transcriptomics, and physiology. Disruption of the REVEILLE2 cooling switch alters regulatory gene expression, impairs circadian timing, and improves photosynthetic capacity. Changes in nuclear gene expression are particularly apparent in the initial hours following chilling, with chloroplast gene expression subsequently up-regulated. The REVEILLE2 cold switch extends our understanding of plants immediate response to cooling. We propose that the circadian component REVEILLE2 restricts plants responses to nocturnal reductions in temperature, thereby enabling appropriate responses to daily environmental changes. Plain language summary: Plants need to respond appropriately to temperature, accounting for the expected daily patterns of reduced temperatures that occur every night relative to the day. Here, we show that a gene expressed at night fulfils this function.

Transport of water, ions and signals from roots to leaves via the xylem vessels is essential for plant life and needs to be tightly regulated. The final composition of the transpiration stream before passage into the shoots is controlled by the xylem-adjacent cell layers, namely xylem parenchyma and pericycle, in the upper part of the root. To unravel regulatory networks in this strategically important location, we generated Arabidopsis lines expressing a nuclear tag under the control of the HKT1 promoter. HKT1 retrieves sodium from the xylem to prevent toxic levels in the shoot, and this function depends on its specific expression in upper root xylem-adjacent tissues. Based on FACS RNA-sequencing and INTACT ChIP-sequencing, we identified the gene repertoire that is preferentially expressed in the tagged cell types and discovered transcription factors experiencing cell-type specific loss of H3K27me3 demethylation. For one of these, ZAT6, we show that H3K27me3-demethylase REF6 is required for de-repression. Analysis of zat6 mutants revealed that ZAT6 activates a suite of cell-type specific downstream genes and restricts Na ⁺ accumulation in the shoots. The combined Files open novel opportunities for ‘bottom-up’ causal dissection of cell-type specific regulatory networks that control root-to-shoot communication under environmental challenge.

The relationship between doctoral research supervisors and their students is crucial for success during doctoral study. Supervisors face increasing complexity in managing these relationships, compounded by job precarity and the pressure to ensure timely doctoral completion. Equally, doctoral students will navigate a competitive job environment with limited time and funding, exacerbated by structural disparities in gender, race, and class outcomes. Our study explores the need for formalised expectation setting and interpersonal familiarisation within supervisor-doctoral student relationships through the development of the Let’s Talk About (LTA) conversation toolkit. LTA was designed with community input, gathering and refining questions from doctoral students and supervisors to explore key areas including expectations, career development, social dynamics, and policy. The toolkit was trialled with supervisor-student pairs, showing significant improvements in understanding and aligning expectations, particularly regarding personal commitments and required support. Results indicated an 81.8% increase in students’ perception of their supervisors’ awareness of their commitments and a 102.5% increase in supervisors’ awareness of students’ needs. These findings underscore the importance of structured and inclusive communication tools that foster supportive academic environments. The study highlights the effectiveness of formalised conversation prompts in enhancing communication and understanding in doctoral supervision, leading to stronger, more productive relationships. The integration of LTA into supervisory practices offers a promising solution to key challenges in doctoral education.