Plants are the source of our food, medicine, construction materials, and the foundation of ecosystems. How can we improve the productivity and resilience of plants? What knowledge, technologies, and tools do we need to generate? These are the long-term questions Zhiyong Wang's lab aim to answer in their research.
Plant growth and survival depend on cellular signaling mechanisms through which plant cells monitor and respond to hormonal signals, environmental cues, and internal nutrient status. Brassinosteroid (BR) is a major growth-promoting hormone that effects on plant height, size, and biomass accumulation.
Plant growth and development are also highly sensitive to environmental signals such as light/dark, temperature, and pathogens. Of course, plant growth depends on nutrients including nitrogen and sugars (product of photosynthesis), and nutrient-sensing mechanisms, such as the Target of Rapamycin (TOR) kinase or O-glycosyltransferases (SPINDLY and SECRET AGENT), are essential for viability.
Zhiyong Wang's research dissects the molecular mechanisms underlying growth responses to these internal and external factors, which have major impacts on plant growth and resilience. To achieve a comprehensive and mechanistic understanding of the growth regulatory system, his lab uses broad research approaches and technologies, including genomics, proteomics, chemical proteomics, microscopy, computation, and structural biology.
Accomplishments
The Wang Lab's research has established the framework of molecular networks that explain how nutritional, hormonal, and environmental signals coordinate the cellular decisions of growth, immunity, and acclimation. Most of the former postdocs and students who made these important discoveries are now leading their own labs in academic institutions.
Among the major achievements of our research, Zhiyong Wang's team has illustrated:
The full brassinosteroid (BR) signaling pathway from the receptor kinase BRI1 to nuclear transcription factor BZR1 and its thousands of target genes.
The growth co-regulation by key growth hormones (BR, auxin, gibberellin) and environmental signals (light and temperature) through direct interactions among their responsive transcription factors, a signal integration mechanism named BAP/D module
The spatiotemporal actions of BR in patterning growth and development in the shoot and root tips.
The mechanisms of crosstalk and component-sharing between BR/BRI1 and other receptor kinase pathways that regulate stomata development and immunity.
The expansive BR-response phosphorylation network controlled by the BIN2/GSK3 kinase.
The genetic variations in the BR-response cis-elements contribute to traits in maize.
The expansive nutrient-signaling networks of protein posttranslational modifications by O-linked β-N-acetylglucosamine (O-GlcNAc) and O-fucose.
The significant overlaps between the BR-regulated phosphorylation network and the nutrient-dependent O-glycosylation networks.
Ongoing Work:
Building upon a large amount of solid data and converging discoveries while taking advantage of the in-house mass spectrometry facility/technologies, our current research continues to make exciting progress toward answering important scientific questions. These include:
How does BR-dependent phosphorylation regulate membrane trafficking, an essential aspect of cell growth?
How do the BR-signaling proteins regulate cytokinesis in plants?
How do cells maintain cell wall integrity during hormone-induced cell expansion?
How do O-GlcNAcylation and O-fucosylation mediate sugar regulation of protein functions and cellular/developmental/physiological processes?
How do BR and sugar signaling, through phosphorylation and O-glycosylation, respectively, co-regulate metabolism and growth?
How do phosphorylation and O-glycosylation crosstalk on common target proteins?
These projects are led by individual postdocs and graduate students, who collaborate and support each other, under my guidance. Together, we are advance a systems-level mechanistic understanding of plant growth and acclimation, and we identify targets and strategies for improving plant productivity and resilience.
Looking Ahead:
What are the main challenges that we still need to overcome? What are the opportunities provided by accumulating knowledge and advancing technologies?
We need to develop tools that enable spatiotemporal manipulation of specific signaling events, and we are developing such tools using nanobodies, molecular sensors, and chemicals/drugs. We would like to expand our research into non-model plants of economic or ecological importance. To do this, we need funding and people to replicate in crops (e.g. maize) some of the productive proteomic experiments (e.g. proximity labeling and O-glycosylation profiling) that we have done in Arabidopsis. We also need to develop better transformation methods to easily transform plants that are difficult or impossible to transform with current methods, and we are testing some novel ideas.
The rapid development in technologies presents exciting opportunities for life science. For example, structures of nearly all proteins can now be predicted by AlphaFold and visualized by cryoEM. This makes it possible to carry out structure-based drug discovery for plant biology. We are using combinations of virtual and experimental screening approaches to identify chemical inhibitors and modulators of plant proteins, developing chemical tools useful for basic research and agricultural application.
Contact Zhiyong Wang
The Wang Lab strives to push the frontier and hope to one day make a real positive impact on our world. If you are interested in joining us, or supporting us, reach out via email to zwang@carnegiescience.edu.
Plants often adapt to adverse or stress conditions via differential growth. The trans-Golgi Network (TGN) has been implicated in stress responses, but it is not clear in what capacity it mediates adaptive growth decisions. In this study, we assess the role of the TGN in stress responses by exploring the interactome of the Transport Protein Particle II (TRAPPII) complex, required for TGN structure and function. We identified physical and genetic interactions between TRAPPII and shaggy-like kinases (GSK3/AtSKs). Kinase assays and pharmacological inhibition provided in vitro and in vivo evidence that AtSKs target the TRAPPII-specific subunit AtTRS120/TRAPPC9. GSK3/AtSK phosphorylation sites in AtTRS120/TRAPPC9 were mutated, and the resulting AtTRS120 phosphovariants subjected to a variety of single and multiple stress conditions in planta. The non-phosphorylatable TRS120 mutant exhibited enhanced adaptation to multiple stress conditions and to osmotic stress whereas the phosphomimetic version was less resilient. Higher order inducible trappii atsk mutants had a synthetically enhanced defect in root gravitropism. Our results suggest that the TRAPPII phosphostatus mediates adaptive responses to abiotic cues. AtSKs are multifunctional kinases that integrate a broad range of signals. Similarly, the TRAPPII interactome is vast and considerably enriched in signaling components. An AtSKTRAPPII interaction would integrate all levels of cellular organization and instruct the TGN, a central and highly discriminate cellular hub, as to how to mobilize and allocate resources to optimize growth and survival under limiting or adverse conditions.
Ethylene plays its essential roles in plant development, growth, and defense responses by controlling the transcriptional reprograming, in which EIN2-C-directed regulation of histone acetylation is the first key-step for chromatin to perceive ethylene signaling. But how the nuclear acetyl coenzyme A (acetyl CoA) is produced to ensure the ethylene-mediated histone acetylation is unknown. Here we report that ethylene triggers the accumulation of the pyruvate dehydrogenase complex (PDC) in the nucleus to synthesize nuclear acetyl CoA to regulate ethylene response. PDC is identified as an EIN2-C nuclear partner, and ethylene triggers its nuclear accumulation. Mutations in PDC lead to an ethylene-hyposensitivity that results from the reduction of histone acetylation and transcription activation. Enzymatically active nuclear PDC synthesize nuclear acetyl CoA for EIN2-C-directed histone acetylation and transcription regulation. These findings uncover a mechanism by which PDC-EIN2 converges the mitochondrial enzyme mediated nuclear acetyl CoA synthesis with epigenetic and transcriptional regulation for plant hormone response.
BRASSINAZONE RESISTANT 1 (BZR1) is a key transcription factor of the brassinosteroid signaling pathway but also a signaling hub that integrates diverse signals that modulate plant growth. Previous studies have shown that starvation causes BZR1 degradation, but the underlying mechanisms are not understood. Here we performed quantitative proteomic analysis of BZR1 interactome under starvation conditions and identified two BZR1-interacting ubiquitin ligases, BAF1 and UPL3. Compared to the wild type, the upl3 mutants show long hypocotyl and increased BZR1 levels when grown under sugar starvation conditions but not when grown on sugar-containing media, indicating a role of UPL3 in BZR1 degradation specifically under starvation conditions. The upl3 mutants showed a reduced survival rate after starvation treatment, supporting the importance of UPL3-mediated BZR1 degradation and growth arrest for starvation survival. Treatments with inhibitors of TARGET of RAPAMYCIN and autophagy altered BZR1 level in the wild type but were less effective in upl3, suggesting that UPL3 mediates the TOR-regulated and autophagy-dependent degradation of BZR1. Further, the UPL3 protein level is increased posttranscriptionally by starvation but decreased by sugar treatment. Our study identifies UPL3 as a key component that mediates sugar regulation of hormone signaling pathways, important for optimal growth and survival in plants.
Plant cell expansion is driven by turgor pressure and regulated by hormones. How plant cells avoid cell wall rupture during hormone-induced cell expansion remains a mystery. Here we show that brassinosteroid (BR), while stimulating cell elongation, promotes the plasma membrane (PM) accumulation of the receptor kinase FERONIA (FER), which monitors cell wall damage and in turn attenuates BR-induced cell elongation to prevent cell rupture. The GSK3-like kinase BIN2 phosphorylates FER, resulting in reduced FER accumulation and translocation from endoplasmic reticulum to PM. By inactivating BIN2, BR signaling promotes dephosphorylation and increases PM accumulation of FER, thereby enhancing the surveillance of cell wall integrity. Our study reveals a vital signaling circuit that coordinates hormone signaling with mechanical sensing to prevent cell bursting during hormone-induced cell expansion.
Protein O-glycosylation is a nutrient-signaling mechanism that plays essential roles in maintaining cellular homeostasis across different species. In plants, SPINDLY (SPY) and SECRET AGENT (SEC) catalyze posttranslational modifications of hundreds of intracellular proteins by O-fucose and O-linked N-acetylglucosamine, respectively. SPY and SEC play overlapping roles in cellular regulation and loss of both SPY and SEC causes embryo lethality in Arabidopsis. Using structure-based virtual screening of chemical libraries followed by in vitro and in planta assays, we identified a SPY O-fucosyltransferase inhibitor (SOFTI). Computational analyses predicted that SOFTI binds to the GDP-fucose-binding pocket of SPY and competitively inhibits GDP-fucose binding. In vitro assays confirmed that SOFTI interacts with SPY and inhibits its O-fucosyltransferase activity. Docking analysis identified additional SOFTI analogs that showed stronger inhibitory activities. SOFTI treatment of Arabidopsis seedlings decreased protein O-fucosylation and caused phenotypes similar to the spy mutants, including early seed germination, increased root hair density, and defect in sugar-dependent growth. By contrast, SOFTI had no visible effect on the spy mutant. Similarly, SOFTI inhibited sugar-dependent growth of tomato seedlings. These results demonstrate that SOFTI is a specific SPY O-fucosyltransferase inhibitor and a useful chemical tool for functional studies of O-fucosylation and potentially for agricultural management.
By directly altering microscopic interactions, pressure provides a powerful tuning knob for the exploration of condensed phases and geophysical phenomena (1). The megabar regime represents an exciting frontier, where recent discoveries include novel high-temperature superconductors, as well as structural and valence phase transitions (2–7). However, at such high pressures, many conventional measurement techniques fail. Here, we demonstrate the ability to perform local magnetometry inside of a diamond anvil cell with sub micron spatial resolution at megabar pressures. Our approach utilizes a shallow layer of Nitrogen-Vacancy (NV) color centers implanted directly within the anvil (8–10); crucially, we choose a crystal cut compatible with the intrinsic symmetries of the NV center to enable functionality at megabar pressures. We apply our technique to characterize a recently discovered hydride superconductor, CeH9 (11). By performing simultaneous magnetometry and electrical transport measurements, we observe the dual signatures of superconductivity: local diamagnetism characteristic of the Meissner effect and a sharp drop of the resistance to near zero. By locally mapping the Meissner effect and flux trapping, we directly image the geometry of superconducting regions, revealing significant inhomogeneities at the micron scale. Our work brings quantum sensing to the megabar frontier and enables the closed loop optimization of superhydride materials synthesis.
