A florigen-expressing subpopulation of companion cells expresses other small proteins and reveals a nitrogen-sensitive repressor.

The precise onset of flowering is crucial to ensure successful plant reproduction. The gene () encodes florigen, a mobile signal produced in leaves that initiates flowering at the shoot apical meristem. In response to seasonal changes, is induced in phloem companion cells located in distal leaf regions.

LTP2 hypomorphs show genotype-by-environment interaction in early seedling traits in Arabidopsis thaliana.

Isogenic individuals can display seemingly stochastic phenotypic differences, limiting the accuracy of genotype-to-phenotype predictions. The extent of this phenotypic variation depends in part on genetic background, raising questions about the genes involved in controlling stochastic phenotypic variation. Focusing on early seedling traits in Arabidopsis thaliana, we found that hypomorphs of the cuticle-related gene LIPID TRANSFER PROTEIN 2 (LTP2) greatly increased variation in seedling phenotypes, including hypocotyl length, gravitropism and cuticle permeability.

hypomorphs show genotype-by-environment interaction in early seedling traits in .

Isogenic individuals can display seemingly stochastic phenotypic differences, limiting the accuracy of genotype-to-phenotype predictions. The extent of this phenotypic variation depends in part on genetic background, raising questions about the genes involved in controlling stochastic phenotypic variation. Focusing on early seedling traits in , we found that hypomorphs of the cuticle-related gene greatly increased variation in seedling phenotypes, including hypocotyl length, gravitropism and cuticle permeability.

AGO1 and HSP90 buffer different genetic variants in Arabidopsis thaliana.

Argonaute 1 (AGO1), the principal protein component of microRNA-mediated regulation, plays a key role in plant growth and development. AGO1 physically interacts with the chaperone HSP90, which buffers cryptic genetic variation in plants and animals. We sought to determine whether genetic perturbation of AGO1 in Arabidopsis thaliana would also reveal cryptic genetic variation, and if so, whether AGO1-dependent loci overlap with those dependent on HSP90.

The regulatory landscape of Arabidopsis thaliana roots at single-cell resolution.

The scarcity of accessible sites that are dynamic or cell type-specific in plants may be due in part to tissue heterogeneity in bulk studies. To assess the effects of tissue heterogeneity, we apply single-cell ATAC-seq to Arabidopsis thaliana roots and identify thousands of differentially accessible sites, sufficient to resolve all major cell types of the root. We find that the entirety of a cell's regulatory landscape and its transcriptome independently capture cell type identity.

Dynamics of Gene Expression in Single Root Cells of .

Single cell RNA sequencing can yield high-resolution cell-type-specific expression signatures that reveal new cell types and the developmental trajectories of cell lineages. Here, we apply this approach to Arabidopsis () root cells to capture gene expression in 3,121 root cells. We analyze these data with Monocle 3, which orders single cell transcriptomes in an unsupervised manner and uses machine learning to reconstruct single cell developmental trajectories along pseudotime.

Complex Relationships between Chromatin Accessibility, Sequence Divergence, and Gene Expression in Arabidopsis thaliana.

Variation in regulatory DNA is thought to drive phenotypic variation, evolution, and disease. Prior studies of regulatory DNA and transcription factors across animal species highlighted a fundamental conundrum: Transcription factor binding domains and cognate binding sites are conserved, while regulatory DNA sequences are not. It remains unclear how conserved transcription factors and dynamic regulatory sites produce conserved expression patterns across species.

Integration of stress-related and reactive oxygen species-mediated signals by Topoisomerase VI in Arabidopsis thaliana.

Environmental stress often leads to an increased production of reactive oxygen species that are involved in plastid-to-nucleus retrograde signaling. Soon after the release of singlet oxygen ((1)O(2)) in chloroplasts of the flu mutant of Arabidopsis, reprogramming of nuclear gene expression reveals a rapid transfer of signals from the plastid to the nucleus. We have identified extraplastidic signaling constituents involved in (1)O(2)-initiated plastid-to-nucleus signaling and nuclear gene activation after mutagenizing a flu line expressing the luciferase reporter gene under the control of the promoter of a (1)O(2)-responsive AAA-ATPase gene (At3g28580) and isolating second-site mutations that lead to a constitutive up-regulation of the reporter gene or abrogate its (1)O(2)-dependent up-regulation.

A gain-of-function mutation of Arabidopsis cryptochrome1 promotes flowering.

Plants use different classes of photoreceptors to collect information about their light environment. Cryptochromes are blue light photoreceptors that control deetiolation, entrain the circadian clock, and are involved in flowering time control. Here, we describe the cry1-L407F allele of Arabidopsis (Arabidopsis thaliana), which encodes a hypersensitive cryptochrome1 (cry1) protein.

Flowering time control.

A dramatic change in the life cycle of plants is the transition to flowering, which is triggered by both environmental signals, such as temperature and photoperiod, and endogenous stimuli. The dicotyledonous annual plant Arabidopsis thaliana is widely used as a model organism to study how these different signals are integrated into a developmental response. The existence of a diverse collection of Arabidopsis flowering time mutants is particularly useful to understand the genetics of flowering time control.

Arabidopsis MSI1 is required for negative regulation of the response to drought stress.

Arabidopsis MSI1 has fundamental functions in plant development. MSI1 is a subunit of Polycomb group protein complexes and Chromatin assembly factor 1, and it interacts with the Retinoblastoma-related protein 1. Altered levels of MSI1 result in pleiotropic phenotypes, reflecting the complexity of MSI1 protein functions.

FLC or not FLC: the other side of vernalization.

Vernalization is the promotion of the competence for flowering by long periods of low temperatures such as those typically experienced during winters. In Arabidopsis, the vernalization response is, to a large extent, mediated by the repression of the floral repressor FLC, and the stable epigenetic silencing of FLC after cold treatments is essential for vernalization. In addition to FLC, other vernalization targets exist in Arabidopsis.