Current opinion in plant biology最新文献

Nitrate is the most abundant form of inorganic nitrogen in aerobic soils, serving both as a nutrient and a signaling molecule. Central to nitrate signaling in higher plants is the intricate balance between local and systemic signaling and response pathways. The interplay between local and systemic responses allows plants to regulate their global gene expression, metabolism, physiology, growth, and development under fluctuating nitrate availability. This review offers an overview of recent discoveries regarding new players on nitrate sensing and signaling, in local and systemic contexts in Arabidopsis thaliana. Additionally, it addresses unanswered questions that warrant further investigation for a better understanding of nitrate signaling and responses in plants.

Plants have a remarkable ability to generate organs with a different identity to the parent organ, called ‘trans-organogenesis’. An example of trans-organogenesis is the formation of roots from stems (a type of adventitious root), which is the first type of root that arose during plant evolution. Despite being ancestral, stem-borne roots are often contextualised through lateral root research, implying that lateral roots precede adventitious roots. In this review we challenge that idea, highlight what is known about stem-borne root development across the plant kingdom, the remarkable diversity in form and function, and the many remaining evolutionary questions. Exploring stem-borne root evolutionary development can enhance our understanding of developmental decision making and the processes by which cells acquire their fates.

Plant microbiome interactions are bidirectional with processes leading to microbiome assembly and processes leading to effects on plants, so called microbiome feedbacks. With belowground focus we systematically decomposed both of these directions into plant and (root and rhizosphere) microbiome components to identify methodological challenges and research priorities. We found that the bidirectionality of plant microbiome interactions presents a challenge for genetic studies. Establishing causality is particularly difficult when a plant mutant has both, an altered phenotype and an altered microbiome. Is the mutation directly affecting the microbiome (e.g., through root exudates), which then causes an altered phenotype of the plant and/or is the altered microbiome the consequence of the mutation altering the plant's phenotype (e.g., root architecture)? Here, we put forward that feedback experiments allow to separate cause and effect and furthermore, they are useful for investigating plant interactions with complex microbiomes in natural soils. They especially allow to investigate the plant genetic basis how plants respond to soil microbiomes and we stress that such microbiome feedbacks are understudied compared to the mechanisms contributing to microbiome assembly. Thinking towards application, this may allow to develop crops with both abilities to assemble a beneficial microbiome and to actively exploit its feedbacks.

For over a decade, the animal field has led the way in using DNA methylation measurements to construct epigenetic clocks of aging. These clocks can predict organismal age with a level of accuracy that surpasses any other molecular proxy known to date. Evidence is finally emerging that epigenetic clocks also exist in plants. However, these clocks appear to differ from those in animals in some key aspects, including in their ability to measure time beyond the life span of an individual. Clock-like epigenetic changes can be found in plant circadian rhythms (scale: 24 h), during plant aging (scale: weeks/centuries), and across plant lineage evolution (scale: decades/millennia). Here, we provide a first classification of these different types of epigenetic clocks, highlight their main features, and discuss their biological basis.

Mitragynine, an alkaloid found in Mitragyna speciosa (kratom), shows promise as a potential alternative to opioids owing to its distinctive indole alkaloid structure and its capacity for pain relief, alleviation of opioid withdrawal symptoms, and anti-inflammatory effects. Recently the intricate process of mitragynine biosynthesis from the precursor strictosidine was elucidated, providing insights into the complex pathways responsible for synthesizing this opioid compound and its related diastereomers. As the search continues for the authentic hydroxylase and methyltransferase crucial for mitragynine formation, leveraging enzymes from other species and exploiting enzyme promiscuity has facilitated heterologous mitragynine biosynthesis in microbes. This highlights the extraordinary flexibility of enzymes in generating a spectrum of variations and analogs of kratom opioids within alternative biological systems.

Prenylated phenolics occur in over 4000 species in the plant kingdom, most of which are known as specialized metabolites with high chemical diversity. Many of them have been identified as pharmacologically active compounds from various medicinal plants, in which prenyl residues play a key role in these activities. Prenyltransferases (PTs) responsible for their biosynthesis have been intensively studied in the last two decades. These enzymes are membrane-bound proteins belonging to the UbiA superfamily that occurs from bacteria to humans, and in particular those involved in plant specialized metabolism show strict specificities for both substrates and products. This article reviews the enzymatic features of plant UbiA PTs, including C- and O-prenylation, molecular evolution, and application of UbiA PTs in synthetic biology.

In recent years, the study of genome dynamics has become a prominent research field due to its influence on understanding the control of gene expression. The study of 3D genome organization has unveiled multiple mechanisms in orchestrating chromosome folding. Growing evidence reveals that these mechanisms are not only important for genome organization, but play a pivotal role in enabling plants to adapt to environmental stimuli. In this review, we provide an overview of the current knowledge concerning epigenetic factors and regulatory elements driving 3D genome dynamics and their responses to external stimuli. We discuss the most recent findings, previous evidence, and explore their implications for future research.

Histone lysine methylation is a highly conserved epigenetic modification across eukaryotes that contributes to creating different dynamic chromatin states, which may result in transcriptional changes. Over the years, an accumulated set of evidence has shown that histone methylation allows plants to align their development with their surroundings, enabling them to respond and memorize past events due to changes in the environment. In this review, we discuss the molecular mechanisms of histone methylation in plants. Writers, readers, and erasers of Arabidopsis histone methylation marks are described with an emphasis on their role in two of the most important developmental transition phases in plants, seed germination and flowering. Further, the crosstalk between different methylation marks is also discussed. An overview of the mechanisms of histone methylation modifications and their biological outcomes will shed light on existing research gaps and may provide novel perspectives to increase crop yield and resistance in the era of global climate change.

The plant cortical microtubule array is an important determinant of cell wall structure and, therefore, plant morphology and physiology. The array consists of dynamic microtubules interacting through frequent collisions. Since the discovery by Dixit and Cyr (2004) that the outcome of such collisions depends on the collision angle, computer simulations have been indispensable in studying array behaviour. Over the last decade, the available simulation tools have drastically improved: multiple high-quality simulation platforms exist with specific strengths and applications. Here, we review how these platforms differ on the critical aspects of microtubule nucleation, flexibility, and local orienting cues; and how such differences affect array behaviour. Building upon concepts and control parameters from theoretical models of collective microtubule behaviour, we conclude that all these factors matter in the debate about what is most important for orienting the array: local cues like mechanical stresses or global cues deriving from the cell geometry.

Transcriptional memory allows organisms to store information about transcriptional reprogramming in response to a stimulus. In plants, this often involves the response to an abiotic stress, which in nature may be cyclical or recurring. Such transcriptional memory confers sustained induction or enhanced re-activation in response to a recurrent stimulus, which may increase chances of survival and fitness. Heat stress (HS) has emerged as an excellent model system to study transcriptional memory in plants, and much progress has been made in elucidating the molecular mechanisms underlying this phenomenon. Here, we review how histone turnover and transcriptional co-regulator complexes contribute to reprogramming of transcriptional responses.