The Plant Journal

doi: 10.1111/tpj.16295pmid: N/A

Balcerowicz, Martin

doi: 10.1111/tpj.16780pmid: 38743849

Andres, Jennifer; Schmunk, Lisa J.; Grau‐Enguix, Federico; Braguy, Justine; Samodelov, Sophia L.; Blomeier, Tim; Ochoa‐Fernandez, Rocio; Weber, Wilfried; Al‐Babili, Salim; Alabadí, David; Blázquez, Miguel A.; Zurbriggen, Matias D.

doi: 10.1111/tpj.16725pmid: 38525669

Gibberellins (GAs) are major regulators of developmental and growth processes in plants. Using the degradation‐based signaling mechanism of GAs, we have built transcriptional regulator (DELLA)‐based, genetically encoded ratiometric biosensors as proxies for hormone quantification at high temporal resolution and sensitivity that allow dynamic, rapid and simple analysis in a plant cell system, i.e. Arabidopsis protoplasts. These ratiometric biosensors incorporate a DELLA protein as a degradation target fused to a firefly luciferase connected via a 2A peptide to a renilla luciferase as a co‐expressed normalization element. We have implemented these biosensors for all five Arabidopsis DELLA proteins, GA‐INSENSITIVE, GAI; REPRESSOR‐of‐ga1‐3, RGA; RGA‐like1, RGL1; RGL2 and RGL3, by applying a modular design. The sensors are highly sensitive (in the low pm range), specific and dynamic. As a proof of concept, we have tested the applicability in three domains: the study of substrate specificity and activity of putative GA‐oxidases, the characterization of GA transporters, and the use as a discrimination platform coupled to a GA agonists' chemical screening. This work demonstrates the development of a genetically encoded quantitative biosensor complementary to existing tools that allow the visualization of GA in planta.

Nguyen, Nghiem D.; Pulsford, Sacha B.; Förster, Britta; Rottet, Sarah; Rourke, Loraine; Long, Benedict M.; Price, G. Dean

doi: 10.1111/tpj.16667pmid: 38321620

The introduction of the carboxysome‐based CO2 concentrating mechanism (CCM) into crop plants has been modelled to significantly increase crop yields. This projection serves as motivation for pursuing this strategy to contribute to global food security. The successful implementation of this engineering challenge is reliant upon the transfer of a microcompartment that encapsulates cyanobacterial Rubisco, known as the carboxysome, alongside active bicarbonate transporters. To date, significant progress has been achieved with respect to understanding various aspects of the cyanobacterial CCM, and more recently, different components of the carboxysome have been successfully introduced into plant chloroplasts. In this Perspective piece, we summarise recent findings and offer new research avenues that will accelerate research in this field to ultimately and successfully introduce the carboxysome into crop plants for increased crop yields.

Meschichi, Anis; Rosa, Stefanie

doi: 10.1111/tpj.16159pmid: 36811211

It has become increasingly clear in recent years that chromosomes are highly dynamic entities. Chromatin mobility and re‐arrangement are involved in many biological processes, including gene regulation and the maintenance of genome stability. Despite extensive studies on chromatin mobility in yeast and animal systems, up until recently, not much had been investigated at this level in plants. For plants to achieve proper growth and development, they need to respond rapidly and appropriately to environmental stimuli. Therefore, understanding how chromatin mobility can support plant responses may offer profound insights into the functioning of plant genomes. In this review, we discuss the state of the art related to chromatin mobility in plants, including the available technologies for their role in various cellular processes.

Dupouy, Gilles; Dong, Yihan; Herzog, Etienne; Chabouté, Marie‐Edith; Berr, Alexandre

doi: 10.1111/tpj.16246pmid: 37067011

The nucleus is a central organelle of eukaryotic cells undergoing dynamic structural changes during cellular fundamental processes such as proliferation and differentiation. These changes rely on the integration of developmental and stress signals at the nuclear envelope (NE), orchestrating responses at the nucleo‐cytoplasmic interface for efficient genomic functions such as DNA transcription, replication and repair. While in animals, correlation has already been established between NE dynamics and chromatin remodeling using last‐generation tools and cutting‐edge technologies, this topic is just emerging in plants, especially in response to mechanical cues. This review summarizes recent data obtained in this field with more emphasis on the mechanical stress response. It also highlights similarities/differences between animal and plant cells at multiples scales, from the structural organization of the nucleo‐cytoplasmic continuum to the functional impacts of NE dynamics.

Ramakrishnan Chandra, Jothipriya; Kalidass, Manikandan; Demidov, Dmitri; Dabravolski, Siarhei A.; Lermontova, Inna

doi: 10.1111/tpj.16445pmid: 37665331

Centromeres are the chromosomal domains, where the kinetochore protein complex is formed, mediating proper segregation of chromosomes during cell division. Although the function of centromeres has remained conserved during evolution, centromeric DNA is highly variable, even in closely related species. In addition, the composition of the kinetochore complexes varies among organisms. Therefore, it is assumed that the centromeric position is determined epigenetically, and the centromeric histone H3 (CENH3) serves as an epigenetic marker. The loading of CENH3 onto centromeres depends on centromere‐licensing factors, chaperones, and transcription of centromeric repeats. Several proteins that regulate CENH3 loading and kinetochore assembly interact with the centromeric transcripts and DNA in a sequence‐independent manner. However, the functional aspects of these interactions are not fully understood. This review discusses the variability of centromeric sequences in different organisms and the regulation of their transcription through the RNA Pol II and RNAi machinery. The data suggest that the interaction of proteins involved in CENH3 loading and kinetochore assembly with centromeric DNA and transcripts plays a role in centromere, and possibly neocentromere, formation in a sequence‐independent manner.

Tourdot, Edouard; Martin, Pascal G. P.; Maza, Elie; Mauxion, Jean‐Philippe; Djari, Anis; Gévaudant, Frédéric; Chevalier, Christian; Pirrello, Julien; Gonzalez, Nathalie

doi: 10.1111/tpj.16646pmid: 38281284

Endoreduplication, during which cells increase their DNA content through successive rounds of full genome replication without cell division, is the major source of endopolyploidy in higher plants. Endoreduplication plays pivotal roles in plant growth and development and is associated with the activation of specific transcriptional programmes that are characteristic of each cell type, thereby defining their identity. In plants, endoreduplication is found in numerous organs and cell types, especially in agronomically valuable ones, such as the fleshy fruit (pericarp) of tomato presenting high ploidy levels. We used the tomato pericarp tissue as a model system to explore the transcriptomes associated with endoreduplication progression during fruit growth. We confirmed that expression globally scales with ploidy level and identified sets of differentially expressed genes presenting only developmental‐specific, only ploidy‐specific expression patterns or profiles resulting from an additive effect of ploidy and development. When comparing ploidy levels at a specific developmental stage, we found that non‐endoreduplicated cells are defined by cell division state and cuticle synthesis while endoreduplicated cells are mainly defined by their metabolic activity changing rapidly over time. By combining this dataset with publicly available spatiotemporal pericarp expression data, we proposed a map describing the distribution of ploidy levels within the pericarp. These transcriptome‐based predictions were validated by quantifying ploidy levels within the pericarp tissue. This in situ ploidy quantification revealed the dynamic progression of endoreduplication and its cell layer specificity during early fruit development. In summary, the study sheds light on the complex relationship between endoreduplication, cell differentiation and gene expression patterns in the tomato pericarp.

Henchiri, Houda; Rayapuram, Naganand; Alhoraibi, Hanna M.; Caïus, José; Paysant‐Le Roux, Christine; Citerne, Sylvie; Hirt, Heribert; Colcombet, Jean; Sturbois, Bénédicte; Bigeard, Jean

doi: 10.1111/tpj.16647pmid: 38281242

The secretory pathway is essential for plant immunity, delivering diverse antimicrobial molecules into the extracellular space. Arabidopsis thaliana soluble N‐ethylmaleimide‐sensitive‐factor attachment protein receptor SNAP33 is a key actor of this process. The snap33 mutant displays dwarfism and necrotic lesions, however the molecular determinants of its macroscopic phenotypes remain elusive. Here, we isolated several new snap33 mutants that exhibited constitutive cell death and H2O2 accumulation, further defining snap33 as an autoimmune mutant. We then carried out quantitative transcriptomic and proteomic analyses showing that numerous defense transcripts and proteins were up‐regulated in the snap33 mutant, among which genes/proteins involved in defense hormone, pattern‐triggered immunity, and nucleotide‐binding domain leucine‐rich‐repeat receptor signaling. qRT‐PCR analyses and hormone dosages supported these results. Furthermore, genetic analyses elucidated the diverse contributions of the main defense hormones and some nucleotide‐binding domain leucine‐rich‐repeat receptor signaling actors in the establishment of the snap33 phenotype, emphasizing the preponderant role of salicylic acid over other defense phytohormones. Moreover, the accumulation of pattern‐triggered immunity and nucleotide‐binding domain leucine‐rich‐repeat receptor signaling proteins in the snap33 mutant was confirmed by immunoblotting analyses and further shown to be salicylic acid‐dependent. Collectively, this study unveiled molecular determinants underlying the Arabidopsis snap33 mutant phenotype and brought new insights into autoimmunity signaling.

Baena, Guillermo; Xia, Lingfeng; Waghmare, Sakharam; Yu, ZhiYi; Guo, Yue; Blatt, Michael R.; Zhang, Ben; Karnik, Rucha

doi: 10.1111/tpj.16649pmid: 38289468

In plants so‐called plasma membrane intrinsic proteins (PIPs) are major water channels governing plant water status. Membrane trafficking contributes to functional regulation of major PIPs and is crucial for abiotic stress resilience. Arabidopsis PIP2;1 is rapidly internalised from the plasma membrane in response to high salinity to regulate osmotic water transport, but knowledge of the underlying mechanisms is fragmentary. Here we show that PIP2;1 occurs in complex with SYNTAXIN OF PLANTS 132 (SYP132) together with the plasma membrane H+‐ATPase AHA1 as evidenced through in vivo and in vitro analysis. SYP132 is a multifaceted vesicle trafficking protein, known to interact with AHA1 and promote endocytosis to impact growth and pathogen defence. Tracking native proteins in immunoblot analysis, we found that salinity stress enhances SYP132 interactions with PIP2;1 and PIP2;2 isoforms to promote redistribution of the water channels away from the plasma membrane. Concurrently, AHA1 binding within the SYP132‐complex was significantly reduced under salinity stress and increased the density of AHA1 proteins at the plasma membrane in leaf tissue. Manipulating SYP132 function in Arabidopsis thaliana enhanced resilience to salinity stress and analysis in heterologous systems suggested that the SNARE influences PIP2;1 osmotic water permeability. We propose therefore that SYP132 coordinates AHA1 and PIP2;1 abundance at the plasma membrane and influences leaf hydraulics to regulate plant responses to abiotic stress signals.