Current opinion in plant biology最新文献

Medicinal plants produce specialized metabolites (SM) that are used as drugs. However, due to low yields of field cultivation and the increasing market demand, this production method often failed to meet supply needs. Biotechnological alternatives, such as in vitro plant cultures, offer promising solutions. Nonetheless, SM production in these systems remains too low for industrial exploitation, necessitating an elicitation step to induce the plant defense metabolism. Traditional elicitation methods mimic environmental conditions that trigger plant-specialized metabolism, often with an artificial signal that mimics microbial interaction. Recent insights into the essential role of the plant microbiota, provides new opportunities for elicitation strategies by microbial coculture in a controlled environment. The successful co-culture of in vitro medicinal plants with synthetic microbial communities could enable sustainable production of pharmaceutically important SM.

The specialized metabolism of St. John's wort, Hypericum perforatum L., is a key focus in medicinal plant research due to its hallmark bioactive compounds hyperforin and hypericin. Known for its traditional medicinal uses dating back to ancient times, St. John's wort is currently used for mild depression therapy. Recent research works have shed light on the biosynthesis of various metabolites in this plant, such as flavonoids, xanthones, hyperforin, and hypericin. The elucidation of these pathways, along with the discovery of novel enzymes like hyperforin synthase, support the pharmaceutical research by enabling scalable production of bioactive compounds for the development of new drugs. Elucidation of the hyperforin biosynthesis based on single-cell RNA-seq is an approach that will be expanded and accelerate the gene discovery and full pathway reconstitution of plant specialized metabolites.

Foliar pathogens exploit natural openings, such as stomata and hydathodes, to invade plants, multiply in the apoplast, and potentially spread through the vasculature. To counteract these threats, plants dynamically regulate stomatal movement and apoplastic water potential, influencing hydathode guttation and water transport. This review highlights recent advances in understanding how phytocytokines, plant small peptides with immunomodulatory functions, regulate these processes to limit pathogen entry and proliferation. Additionally, we discuss the coordinated actions of stomatal movement, hydathode guttation, and the vascular system in restricting pathogen entry, multiplication, and dissemination. We also explore future perspectives and key questions arising from these findings, aiming to advance our knowledge of plant immunity and improve disease resistance strategies.

Plant cell cortical microtubules are located beneath the plasma membrane and direct the location of cellulose synthases during interphase, influencing cell morphology. Microtubule-associated proteins (MAPs) regulate these microtubules in response to growth and environmental stimuli. This review focuses on recent advances in understanding microtubule nucleation mechanisms in plants and the spatiotemporal regulation of cortical arrays via phytohormone signaling. Emphasis is placed on the conserved nature of the gamma-tubulin ring complex (γTuRC) and plant-specific components. The discussion includes the role of the Augmin complex and the distinct function of the Msd1-Wdr8 complex in plants. We also explore the effects of hormone signaling, particularly brassinosteroids, on the microtubule regulatory apparatus. The interplay between hormone signaling pathways and microtubule dynamics, including phosphorylation events and post-translational modifications, is also addressed. Finally, the impact of environmental signals and the role of protein post-translational modifications in regulating microtubule organization are suggested for future research.

Plant pathogens deploy specialized proteins to aid disease progression, some of these proteins function in the apoplast and constitute proteases. Extracellular virulence proteases have been described to play roles in plant cell wall manipulation and immune evasion. In this review, we discuss the evidence for the hypothesized virulence functions of bacterial, fungal, and oomycete extracellular proteases. We highlight the contrast between the low number of elucidated functions for these proteins and the size of extracellular protease repertoires among pathogens. Finally, we suggest that the refinement of in planta ‘omics’ approaches, combined with recent advances in modeling and mechanism-based methods for trapping substrates finally make it possible to address this knowledge gap.

Plant-specific receptor-like protein kinases (RLKs) are essential for pathogen recognition during pattern-triggered immunity. Together with coreceptors and associated proteins, they act as bona fide immune receptors, perceiving a variety of microbe-associated molecular patterns or damage-associated molecular patterns. The cysteine-rich receptor-like kinases (CRKs) form one of the biggest subgroups of RLKs, but so far, their ligands have not been identified. It has been shown that CRKs play important roles in plant immunity and defense responses as well as in response to abiotic stimuli and in control of plant development. However, molecular information on how CRKs integrate with the known framework of signaling components controlling early defense responses remains enigmatic.

Reactive oxygen species (ROS) is a collective term for highly reactive oxygen derivatives, including singlet oxygen, hydroxyl radicals, superoxide anions, and hydrogen peroxide. In plants, ROS are produced in apoplasts, chloroplasts, mitochondria, and peroxisomes. Although ROS are toxic when their levels exceed a certain threshold, low-concentration ROS can serve as essential signaling molecules for plant growth and development, as well as plant responses to abiotic and biotic stresses. Various aspects of the role of ROS in plants have been discussed in previous reviews. In this review, we first summarize recent progress in the regulatory mechanisms of apoplastic ROS signaling and then propose its potential roles in plant defense against vascular pathogens to provide new ideas for the prevention and control of vascular diseases.

Plants produce diverse small molecules rapidly in response to localized pathogenic attack. Some of the molecules are able to migrate systemically as mobile signals, leading to the immune priming that protects the distal tissues against future infections by a broad-spectrum of invaders. Such form of defense is unique in plants and is known as systemic acquired resistance (SAR). There are many small molecules identified so far with important roles in the systemic immune signaling, some may have the potential to act as the mobile systemic signal in SAR establishment. Here, we summarize the recent advances in SAR research, with a focus on the role and mechanisms of different small molecules in systemic immune signaling.

The phenomenon of multicellular compartmentation in biosynthetic pathways has been documented for only a limited subset of specialized metabolites, despite its hypothesized significance in facilitating plant survival and adaptation to environmental stress. Transporters that shuttle metabolic intermediates between cells are hypothesized to be integral components enabling compartmentalized biosynthesis. Nevertheless, our understanding of the multicellular compartmentation of plant specialized metabolism and the associated intermediate transporters remains incomplete. The emergence of single-cell and spatial multiomics techniques holds promise for shedding light on unresolved questions in this field, such as the prevalence of multicellular compartmentation across the plant kingdom and the specific types of specialized metabolites whose biosynthetic pathways are prone to compartmentation. Advancing our understanding of the mechanisms underlying multicellular compartmentation will contribute to improving the production of specialized target metabolites through metabolic engineering or synthetic biology.

The essential role of water-conducting xylem tissue in plant growth and crop yield is well-established. However, the molecular mechanisms underlying xylem formation and its unique functionality, which is acquired post-mortem, remain poorly understood. Recent advancements in genetic tools and model systems have significantly enhanced the ability to microscopically study xylem development, particularly its distinctive cell wall patterning. Early molecular mechanisms enabling pattern formation have been elucidated and validated through computational models. Despite these advancements, numerous questions remain unresolved but are approachable with current methodologies. This mini-review takes in the latest research findings in xylem cell wall synthesis and patterning and highlights prospective directions for future investigations.