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Summary: Greenbeards are selfish genetic elements that make their bearers behave either altruistically towards individuals bearing similar greenbeard copies or harmfully towards individuals bearing different copies. They were first proposed by W. D. Hamilton over 50 yr ago, to illustrate that kin selection may operate at the level of single genes. Examples of greenbeards have now been reported in a wide range of taxa, but they remain undocumented in plants. In this paper, we discuss the theoretical likelihood of greenbeard existence in plants. We then question why the greenbeard concept has never been applied to plants and speculate on how hypothetical greenbeards could affect plant–plant interactions. Finally, we point to different research directions to improve our knowledge of greenbeards in plants. [ABSTRACT FROM AUTHOR]

Yoselin Benitez Alfonso, a professor in interdisciplinary plant sciences at the University of Leeds, shares her journey and passion for plant science. Growing up in Cuba, she developed a love for nature and later pursued a degree in chemistry in Spain. Despite not having a biology background, she taught herself plant biology and became interested in plasmodesmata research. She is motivated by her love for research, the success of her students, and the impact of her contributions to teaching and diversity. She considers her father and various mentors as role models and enjoys reading papers on plasmodesmata research and plant symbiosis. Her favorite plant is the olive tree due to its symbolism, climate resilience, and economic significance. Yoselin is also involved in the Black in Plant Science Network and has received recognition for her leadership and academic achievements. [Extracted from the article]

The article discusses a comment made by Bourke et al. regarding the method described in Chen et al.'s paper on mapping quantitative trait loci (QTL) in autotetraploids. Chen et al. argue that their comment is correct based on facts and statistical principles. They explain that the method used in Bourke et al.'s paper lacks an essential component, which is genetic linkage analysis between QTLs and surrounding markers for QTL mapping in an outbred autotetraploid segregating population. Chen et al. also address the terminology and methodology used by Bourke et al., pointing out inconsistencies and inaccuracies. They conclude that their own method enables QTL mapping in autotetraploid species under a novel tetrasomic inheritance model and is based on rigorous scientific and statistical principles. [Extracted from the article]

Silke Robatzek, a Heisenberg Professor at Ludwig-Maximilian-University in Munich, Germany, discusses her interest in plant science and her decision to pursue a career in research. She is motivated by her curiosity and a desire to contribute to society through discovering new knowledge. Robatzek also highlights the importance of mentors and role models in her career, and she mentions her favorite papers from the New Phytologist journal. She expresses her fascination with olive trees and their genetic diversity in terms of plant immunity. [Extracted from the article]

This document is an interview with Debora Gasperini, a researcher in plant science. Gasperini explains that her interest in research began at a young age, inspired by her love for the natural world and engaging science classes. She chose to study molecular biology and became fascinated with plants due to their unique communication and resilience. Gasperini is motivated by the thrill of discovery and problem-solving, and she considers scientists like Rita Levi-Montalcini and Katherine Esau as role models for their passion and perseverance. She also discusses her favorite papers from the journal New Phytologist, which covers a wide range of plant science topics. Gasperini appreciates the adaptability and enduring nature of plants, which continue to inspire her research. [Extracted from the article]

This article is an interview with Peter J. Franks, a plant scientist who specializes in plant physiology and plant-climate interactions. Franks discusses his interest in plant science, which was sparked by his experiences in rainforests and his fascination with the diverse uses of plants by indigenous tribes. He also explains his decision to pursue a career in research, driven by his curiosity and the desire to contribute to scientific knowledge. Franks mentions his role models in the field and highlights some recent papers in the journal New Phytologist that have made significant advancements in understanding stomatal control and signaling in plants. He also shares his favorite plant species, including the extinct Cooksonia and the living fossil Austrobaileya scandens. Overall, Franks' research aims to integrate geological, molecular, and physiological information to understand the co-evolution of Earth's climate and vegetation. [Extracted from the article]

This article is a Commentary on the Virtual Issue 'Methane emissions from tree stems – current knowledge and challenges' that includes the following papers: Barba et al. (2019), Bréchet et al. (2021), Covey & Megonigal (2019), Feng et al. (2022), Flanagan et al. (2021), Jeffrey et al. (2019, 2021, 2023), Kohl et al. (2019), Machacova et al. (2021a,b, 2023), Megonigal et al. (2020), Pangala et al. (2013, 2014), Pitz & Megonigal (2017), Plain et al. (2019), Putkinen et al. (2021), Sjögersten et al. (2020), Takahashi et al. (2022), Tenhovirta et al. (2022), Wang et al. (2016), and Yip et al. (2018). Access the Virtual Issue at www.newphytologist.com/virtualissues. [ABSTRACT FROM AUTHOR]

This document is an interview with Ari Sadanandom, a Professor of Plant Molecular Sciences at the University of Durham. Sadanandom discusses his interest in plant science, his decision to pursue a career in research, and his motivations as a scientist. He also mentions his role models and inspirations throughout his career. Additionally, Sadanandom highlights some of his favorite papers from the journal New Phytologist, focusing on topics such as plant immunity, root development, and protein modifications. Finally, he shares his favorite plant, the Mimosa plant, and provides information about his research on protein modifications and its implications for agriculture. [Extracted from the article]

Summary: Light intensity and quality influence photosynthesis directly but also have an indirect effect by increasing stomatal apertures and enhancing gas exchange. Consequently, in areas such as the upper canopy, a high water demand for transpiration and temperature regulation is created. This paper explores how light intensity and the natural high Blue‐Light (BL) : Red‐Light (RL) ratio in these areas, is important for controlling leaf hydraulic conductance (Kleaf) by BL signal transduction, increasing water permeability in cells surrounding the vascular tissue, in supporting the enormous water demands. Conversely, shaded inner‐canopy areas receive less radiation, have lower water and cooling demands, and exhibit reduced Kleaf due to diminished intensity and BL induction. Intriguingly, shaded leaves display higher water‐use efficiency (compared with upper‐canopy) due to decreased transpiration and cooling requirements while the presence of RL supports photosynthesis. [ABSTRACT FROM AUTHOR]

Alison Smith, a Professor of Plant Biochemistry at the University of Cambridge, discusses her interest in plant science and her career in research. She explains that her fascination with the productivity of gardening as a child led her to study Biochemistry in university and eventually specialize in photosynthetic organisms. Smith finds motivation in working with students and postdocs, as well as in the endless fascination of scientific discoveries. She also mentions several mentors and colleagues who have influenced her, including notable women plant scientists. Smith appreciates the variety of topics covered in the journal New Phytologist and highlights some of her favorite papers. Finally, she shares her favorite plant, the rose, for its showiness, and her favorite photosynthetic organisms, microalgae, for their diversity and potential in biotechnology. [Extracted from the article]

Antony N. Dodd is a plant scientist who is interested in chronobiology and circadian rhythms. He was inspired to study plant biology after attending lectures by Howard Griffiths, which showed how biochemical processes in plants could be studied over 24-hour cycles. Dodd pursued a career in research because he was fascinated by the control of daily cycles of Crassulacean acid metabolism in plants. He is motivated by the social element of science and the interactions with his research group and colleagues. Dodd provides advice for scientists, such as investing time to get things right, not only chasing big papers, and being collegial. He also discusses his favorite New Phytologist papers, which explore the use of chemical biology to study circadian rhythms in plants. Dodd mentions two favorite plant species, Agave americana and Aegagropila linnaei, and their significance in his research. [Extracted from the article]

This document is a profile of Martina Legris, a postdoctoral researcher at the Center for Integrative Genomics at the University of Lausanne in Switzerland. Martina's interest in plant science was inspired by her upbringing in a family of veterinarians and farmers, as well as her experiences playing with plants and animals in nature. She decided to pursue a career in research after participating in scientific meetings and outreach activities, where she met inspiring scientists and learned about their research. Martina is motivated by her love for her work and the sense of duty to contribute to society. She considers her mentors and female colleagues with children to be role models, and she appreciates the opportunity to choose her research topics and the variety of tasks in her everyday life. Martina's research focuses on plant development in response to light and temperature signals from the environment. She has published papers on the convergence of light and temperature signaling pathways in plants and the regulation of meristem activity. Martina's favorite plant is Ceiba speciosa, a large tree native to South America, and she also has a fondness for Arabidopsis thaliana, a tiny plant that has allowed her to uncover exciting aspects of plant biology. [Extracted from the article]

This article is an Editorial to the Virtual issue on 'Remote sensing' that includes the following papers Chavana‐Bryant et al. (2017), Coupel‐Ledru et al. (2022), Cushman & Machado (2020), Disney (2019), D'Odorico et al. (2020), Dong et al. (2022), Fischer et al. (2019), Gamon et al. (2023), Gu et al. (2019), Guillemot et al. (2020), Jucker (2021), Koh et al. (2022), Konings et al. (2019), Kothari et al. (2023), Martini et al. (2022), Richardson (2019), Santini et al. (2021), Schimel et al. (2019), Serbin et al. (2019), Smith et al. (2019, 2020), Still et al. (2021), Stovall et al. (2021), Wang et al. (2020), Wong et al. (2020), Wu et al. (2021), Wu et al. (2017), Wu et al. (2018), Wu et al. (2019), Xu et al. (2021), Yan et al. (2021). Access the Virtual Issue at www.newphytologist.com/virtualissues. [ABSTRACT FROM AUTHOR]

Summary: A surge of papers have reported low leaf vulnerability to xylem embolism during drought. Here, we focus on the less studied, and more sensitive, outside‐xylem leaf hydraulic responses to multiple internal and external conditions. Studies of 34 species have resolved substantial vulnerability to dehydration of the outside‐xylem pathways, and studies of leaf hydraulic responses to light also implicate dynamic outside‐xylem responses. Detailed experiments suggest these dynamic responses arise at least in part from strong control of radial water movement across the vein bundle sheath. While leaf xylem vulnerability may influence leaf and plant survival during extreme drought, outside‐xylem dynamic responses are important for the control and resilience of water transport and leaf water status for gas exchange and growth. [ABSTRACT FROM AUTHOR]

Summary: Cellulose is an essential component of plant cell walls and an economically important source of food, paper, textiles, and biofuel. Despite its economic and biological significance, the regulation of cellulose biosynthesis is poorly understood. Phosphorylation and dephosphorylation of cellulose synthases (CESAs) were shown to impact the direction and velocity of cellulose synthase complexes (CSCs). However, the protein kinases that phosphorylate CESAs are largely unknown. We conducted research in Arabidopsis thaliana to reveal protein kinases that phosphorylate CESAs.In this study, we used yeast two‐hybrid, protein biochemistry, genetics, and live‐cell imaging to reveal the role of calcium‐dependent protein kinase32 (CPK32) in the regulation of cellulose biosynthesis in A. thaliana.We identified CPK32 using CESA3 as a bait in a yeast two‐hybrid assay. We showed that CPK32 phosphorylates CESA3 while it interacts with both CESA1 and CESA3. Overexpressing functionally defective CPK32 variant and phospho‐dead mutation of CESA3 led to decreased motility of CSCs and reduced crystalline cellulose content in etiolated seedlings. Deregulation of CPKs impacted the stability of CSCs.We uncovered a new function of CPKs that regulates cellulose biosynthesis and a novel mechanism by which phosphorylation regulates the stability of CSCs. [ABSTRACT FROM AUTHOR]

Summary: Seminal scientific papers positing that mycorrhizal fungal networks can distribute carbon (C) among plants have stimulated a popular narrative that overstory trees, or 'mother trees', support the growth of seedlings in this way. This narrative has far‐reaching implications for our understanding of forest ecology and has been controversial in the scientific community. We review the current understanding of ectomycorrhizal C metabolism and observations on forest regeneration that make the mother tree narrative debatable. We then re‐examine data and conclusions from publications that underlie the mother tree hypothesis. Isotopic labeling methods are uniquely suited for studying element fluxes through ecosystems, but the complexity of mycorrhizal symbiosis, low detection limits, and small carbon discrimination in biological processes can cause researchers to make important inferences based on miniscule shifts in isotopic abundance, which can be misleading. We conclude that evidence of a significant net C transfer via common mycorrhizal networks that benefits the recipients is still lacking. Furthermore, a role for fungi as a C pipeline between trees is difficult to reconcile with any adaptive advantages for the fungi. Finally, the hypothesis is neither supported by boreal forest regeneration patterns nor consistent with the understanding of physiological mechanisms controlling mycorrhizal symbiosis. [ABSTRACT FROM AUTHOR]

This article is a Commentary on Guo et al. (2023), 238: 1004–1018. [ABSTRACT FROM AUTHOR]

This article is a Commentary on Osborne et al. (2023), 238: 1305–1317. [ABSTRACT FROM AUTHOR]

Summary: Vegetated coastal ecosystems sequester carbon rapidly relative to terrestrial ecosystems. Coastal wetlands are poorly represented in land surface models, but work is underway to improve process‐based, predictive modeling of these ecosystems. Here, we identify guiding questions, potential simulations, and data needs to make progress in improving representation of vegetation in terrestrial–aquatic interfaces, with a focus on coastal and estuarine ecosystems. We synthesize relevant plant traits and environmental controls on vegetation that influence carbon cycling in coastal ecosystems. We propose that models include separate plant functional types (PFTs) for mangroves, graminoid salt marshes, and succulent salt marshes to adequately represent the variation in aboveground and belowground productivity between common coastal wetland vegetation types. We also discuss the drivers and carbon storage consequences of shifts in dominant PFTs. We suggest several potential approaches to represent the diversity in vegetation tolerance and adaptations to fluctuations in salinity and water level, which drive key gradients in coastal wetland ecosystems. Finally, we discuss data needs for parameterizing and evaluating model implementations of coastal wetland vegetation types and function. [ABSTRACT FROM AUTHOR]

Summary: Wildfires are a global crisis, but current fire models fail to capture vegetation response to changing climate. With drought and elevated temperature increasing the importance of vegetation dynamics to fire behavior, and the advent of next generation models capable of capturing increasingly complex physical processes, we provide a renewed focus on representation of woody vegetation in fire models. Currently, the most advanced representations of fire behavior and biophysical fire effects are found in distinct classes of fine‐scale models and do not capture variation in live fuel (i.e. living plant) properties. We demonstrate that plant water and carbon dynamics, which influence combustion and heat transfer into the plant and often dictate plant survival, provide the mechanistic linkage between fire behavior and effects. Our conceptual framework linking remotely sensed estimates of plant water and carbon to fine‐scale models of fire behavior and effects could be a critical first step toward improving the fidelity of the coarse scale models that are now relied upon for global fire forecasting. This process‐based approach will be essential to capturing the influence of physiological responses to drought and warming on live fuel conditions, strengthening the science needed to guide fire managers in an uncertain future. [ABSTRACT FROM AUTHOR]

Summary: Membrane‐localized transporters constitute important components for specialized metabolism in plants. However, due to the vast array of specialized metabolites produced by plants, and the large families of transporter genes, knowledge about the intracellular and intercellular transport of plant metabolites is still in its infancy.Cucurbitacins are bitter and defensive triterpenoids produced mainly in the cucurbits. Using a comparative genomics and multi‐omics approach, a MATE gene (CsMATE1), physically clustered with cucurbitacin C (CuC) biosynthetic genes, was identified and functionally shown to sequester CuC in cucumber leaf mesophyll cells.Notably, the CuC transport process is strictly co‐regulated with CuC biosynthesis. CsMATE1 clustering with bitterness biosynthesis genes may provide benefits and a basis for this feedback regulation on CuC sequestration and biosynthesis.Identification of transport systems for plant‐specialized metabolites can accelerate the metabolic engineering of high‐value‐added compounds by simplifying their purification process. [ABSTRACT FROM AUTHOR]

Summary: To what degree plant ecosystems thermoregulate their canopy temperature (Tc) is critical to assess ecosystems' metabolisms and resilience with climate change, but remains controversial, with opinions from no to moderate thermoregulation capability.With global datasets of Tc, air temperature (Ta), and other environmental and biotic variables from FLUXNET and satellites, we tested the 'limited homeothermy' hypothesis (indicated by Tc & Ta regression slope < 1 or Tc < Ta around midday) across global extratropics, including temporal and spatial dimensions.Across daily to weekly and monthly timescales, over 80% of sites/ecosystems have slopes ≥1 or Tc > Ta around midday, rejecting the above hypothesis. For those sites unsupporting the hypothesis, their Tc–Ta difference (ΔT) exhibits considerable seasonality that shows negative, partial correlations with leaf area index, implying a certain degree of thermoregulation capability. Spatially, site‐mean ΔT exhibits larger variations than the slope indicator, suggesting ΔT is a more sensitive indicator for detecting thermoregulatory differences across biomes. Furthermore, this large spatial‐wide ΔT variation (0–6°C) is primarily explained by environmental variables (38%) and secondarily by biotic factors (15%).These results demonstrate diverse thermoregulation patterns across global extratropics, with most ecosystems negating the 'limited homeothermy' hypothesis, but their thermoregulation still occurs, implying that slope < 1 or Tc < Ta are not necessary conditions for plant thermoregulation. See also the Commentary on this article by Drake, 238: 921–923. [ABSTRACT FROM AUTHOR]

Summary: Many plant species can give rise to embryos from somatic cells after a simple hormone treatment, illustrating the remarkable developmental plasticity of differentiated plant cells. However, many species are recalcitrant to somatic embryo formation for unknown reasons, which poses a significant challenge to agriculture, where somatic embryogenesis is an important tool to propagate desired genotypes. The micro‐RNA394 (miR394) promotes shoot meristem maintenance in Arabidopsis thaliana, but the underlying mechanisms have remained elusive.We analyzed whether miR394 affects indirect somatic embryogenesis and determined the transcriptome of embryogenic callus upon miR394‐enhanced somatic embryogenesis.We show that ectopic miR394 expression enhances somatic embryogenesis in the recalcitrant Ler accession when co‐expressed with the transcription factor WUSCHEL (WUS) and that miR394 acts in this process through silencing the target LEAF CURLING RESPONSIVENESS (LCR). Furthermore, we show that higher endogenous miR394 levels are required for the elevated embryogenic potential of the Columbia accession compared with Ler, providing a mechanistic explanation for this natural variation.Our transcriptional analysis provides a framework for miR394 function in regulating pluripotency by expanding WUS‐mediated direct transcriptional repression. [ABSTRACT FROM AUTHOR]

Summary: Numerous plant endogenous mRNAs move via phloem and thus affect the growth and development of long‐distant organs. mRNAs are transported with RNA‐binding proteins forming a ribonucleoprotein complex. However, it remains elusive how such RNP complex assembles and facilitates mRNA trafficking.Protease digestion and RNA immunoprecipitation were used to investigate the RNP assembly function of the complete Chaperonin Containing T‐complex Polypeptide‐1. In situ hybridization, hairy root transformation, microprojectile bombardment, and grafting experiments demonstrate the role of CCT complex in the transport of a PbWoxT1‐PbPTB3 RNP complex in Pyrus betulaefolia.PbCCT5 silenced caused defective movement of GFP‐PbPTB3 and GFP‐PbWoxT1 from hairy roots to new leaves via the phloem. PbCCT5 is shown to interact with PbPTB3. PbCCT complex enhanced PbPTB3 stabilization and permitted assembly of PbWoxT1 and PbPTB3 into an RNP complex. Furthermore, silencing of individual CCT subunits inhibited the intercellular movement of GFP‐PbPTB3 and long‐distance trafficking of PbWoxT1 and PbPTB3 in grafted plants.Taken together, the CCT complex assembles PbPTB3 and PbWoxT1 into an RNP complex in the phloem in order to facilitate the long‐distance trafficking of PbWoxT1 in P. betulaefolia. This study therefore provides important insights into the mechanism of RNP complex formation and transport. [ABSTRACT FROM AUTHOR]

Summary: Fructans in angiosperms play essential roles in physiological functions and environmental adaptations. As a major source of industrial fructans (especially inulin‐type), chicory (Cichorium intybus L.) is a model species for studying fructan biosynthesis. However, the genes underlying this process and their evolutionary history in angiosperms remain elusive.We combined multiple sequencing technologies to assemble and annotate the chicory genome and scan its (epi)genomic features, such as genomic components, DNA methylation, and three‐dimensional (3D) structure. We also performed a comparative genomics analysis to uncover the associations between key traits and gene families.We achieved a nearly complete chicory genome assembly and found that continuous bursts of a few highly active retrotransposon families largely shaped the (epi)genomic characteristics. The highly methylated genome with its unique 3D structure potentially influences critical biological processes. Our comprehensive comparative genomics analysis deciphered the genetic basis for the rich sesquiterpene content in chicory and indicated that the fructan‐accumulating trait resulted from convergent evolution in angiosperms due to shifts in critical sites of fructan‐active enzymes.The highly characterized chicory genome provides insight into Asteraceae evolution and fructan biosynthesis in angiosperms. [ABSTRACT FROM AUTHOR]

Summary: The adaptation of weeds to herbicide is both a significant problem in agriculture and a model of rapid adaptation. However, significant gaps remain in our knowledge of resistance controlled by many loci and the evolutionary factors that influence the maintenance of resistance.Here, using herbicide‐resistant populations of the common morning glory (Ipomoea purpurea), we perform a multilevel analysis of the genome and transcriptome to uncover putative loci involved in nontarget‐site herbicide resistance (NTSR) and to examine evolutionary forces underlying the maintenance of resistance in natural populations.We found loci involved in herbicide detoxification and stress sensing to be under selection and confirmed that detoxification is responsible for glyphosate (RoundUp) resistance using a functional assay. We identified interchromosomal linkage disequilibrium (ILD) among loci under selection reflecting either historical processes or additive effects leading to the resistance phenotype. We further identified potential fitness cost loci that were strongly linked to resistance alleles, indicating the role of genetic hitchhiking in maintaining the cost.Overall, our work suggests that NTSR glyphosate resistance in I. purpurea is conferred by multiple genes which are potentially maintained through generations via ILD, and that the fitness cost associated with resistance in this species is likely a by‐product of genetic hitchhiking. [ABSTRACT FROM AUTHOR]

Summary: The architecture of root systems is an important driver of plant fitness, competition and ecosystem processes. However, the methodological difficulty of mapping roots hampers the study of these processes. Existing approaches to match individual plants to belowground samples are low throughput and species specific. Here, we developed a scalable sequencing‐based method to map the root systems of individual trees across multiple species. We successfully applied it to a tropical dry forest community in the Brazilian Caatinga containing 14 species.We sequenced all 42 individual shrubs and trees in a 14 × 14 m plot using double‐digest restriction site‐associated sequencing (ddRADseq). We identified species‐specific markers and individual‐specific haplotypes from the data. We matched these markers to the ddRADseq data from 100 mixed root samples from across the centre (10 × 10 m) of the plot at four different depths using a newly developed R package.We identified individual root samples for all species and all but one individual. There was a strong significant correlation between belowground and aboveground size measurements, and we also detected significant species‐level root‐depth preference for two species.The method is more scalable and less labour intensive than the current techniques and is broadly applicable to ecology, forestry and agricultural biology. See also the Commentary on this article by Jones, 238: 924–925. [ABSTRACT FROM AUTHOR]

Keywords: adaptation; environment; plant diversity; plant science questions; societal importance; species interactions EN adaptation environment plant diversity plant science questions societal importance species interactions 464 469 6 03/21/23 20230415 NES 230415 Introduction In 2011, we published 100 important questions for plant science research pertaining to (A) society, (B) environment and adaptation, (C) species interactions, (D) understanding and utilising plant cells, and (E) diversity (Grierson I et al i ., [33]). Despite relevance to urgent challenges including climate change prediction, adaptation, mitigation, food security and human health, plant science has received far less funding than fields such as health research (e.g. £50 M for plant science vs £4.8 B for health research in the UK in 2018). One hundred important questions for plant science - reflecting on a decade of plant research Plant science has made important contributions to improving models of climate change and its consequences (Ikeda I et al i ., [40]; Rötter I et al i ., [76]; Merganicová I et al i ., [60]; Kawamiya I et al i ., [48]) (A6, D22). [Extracted from the article]

Summary: The 'One Hundred Important Questions Facing Plant Science Research' project aimed to capture a global snapshot of the current issues and future questions facing plant science. This revisiting builds on the original 2011 paper. Over 600 questions were collected from anyone interested in plants, which were reduced to a final list of 100 by four teams of global panellists. There was remarkable consensus on the most important topics between the global subpanels. We present the top 100 most important questions facing plant science in 2022, ranging from how plants can contribute to tackling climate change, to plant‐defence priming and epigenome plasticity. We also provide explanations of why each question is important. We demonstrate how focussing on climate change, community and protecting plant life has become increasingly important for plant science over the past 11 years. This revisiting illustrates the collaborative and international need for long‐term funding of plant science research, alongside the broad community‐driven efforts to actively ameliorate and halt climate change, while adapting to its consequences. [ABSTRACT FROM AUTHOR]

Summary: Every existing optimal stomatal model uses photosynthetic carbon assimilation as a proxy for plant evolutionary fitness. However, assimilation and growth are often decoupled, making assimilation less ideal for representing fitness when optimizing stomatal conductance to water vapor and carbon dioxide. Instead, growth should be considered a closer proxy for fitness.We hypothesize stomata have evolved to maximize turgor‐driven growth, instead of assimilation, over entire plants' lifetimes, improving their abilities to compete and reproduce. We develop a stomata model that dynamically maximizes whole‐stem growth following principles from turgor‐driven growth models. Stomata open to assimilate carbohydrates that supply growth and osmotically generate turgor, while stomata close to prevent losses of turgor and growth due to negative water potentials.In steady state, the growth optimization model captures realistic stomatal, growth, and carbohydrate responses to environmental cues, reconciles conflicting interpretations within existing stomatal optimization theories, and explains patterns of carbohydrate storage and xylem conductance observed during and after drought.Our growth optimization hypothesis introduces a new paradigm for stomatal optimization models, elevates the role of whole‐plant carbon use and carbon storage in stomatal functioning, and has the potential to simultaneously predict gross productivity, net productivity, and plant mortality through a single, consistent modeling framework. See also the Commentary on this article by Buckley, 238: 457–460. [ABSTRACT FROM AUTHOR]

Summary: Optimality‐based models of stomatal conductance unify biophysical and evolutionary constraints and can improve predictions of land‐atmosphere carbon and water exchange. Recent models incorporate hydraulic constraints by penalizing excessive stomatal opening in relation to hydraulic damage caused by low water potentials. We used simulation models to test whether penalties based solely on vulnerability curves adequately represent the optimality hypothesis, given that they exclude the effects of kinetic factors on stomatal behavior and integrated carbon balance.To quantify the effects of nonsteady‐state phenomena on the landscape of short‐term hydraulic risk, we simulated diurnal dynamics of leaf physiology for 10 000 patches of leaf in a canopy and used a ray‐tracing model, Helios, to simulate realistic variation in sunfleck dynamics.Our simulations demonstrated that kinetic parameters of leaf physiology and sunfleck properties influence the economic landscape of short‐term hydraulic risk, as characterized by the effect of stomatal strategy (gauged by the water potential causing a 50% hydraulic penalty) on both aggregated carbon gain and the aggregated carbon cost of short‐term hydraulic risk.Hydraulic penalties in optimization models should be generalized to allow their parameters to account for kinetic factors, in addition to parameters of hydraulic vulnerability. [ABSTRACT FROM AUTHOR]

Summary: Plant ecologists use functional traits to describe how plants respond to and influence their environment. Reflectance spectroscopy can provide rapid, non‐destructive estimates of leaf traits, but it remains unclear whether general trait‐spectra models can yield accurate estimates across functional groups and ecosystems.We measured leaf spectra and 22 structural and chemical traits for nearly 2000 samples from 103 species. These samples span a large share of known trait variation and represent several functional groups and ecosystems, mainly in eastern Canada. We used partial least‐squares regression (PLSR) to build empirical models for estimating traits from spectra.Within the dataset, our PLSR models predicted traits such as leaf mass per area (LMA) and leaf dry matter content (LDMC) with high accuracy (R2 > 0.85; %RMSE < 10). Models for most chemical traits, including pigments, carbon fractions, and major nutrients, showed intermediate accuracy (R2 = 0.55–0.85; %RMSE = 12.7–19.1). Micronutrients such as Cu and Fe showed the poorest accuracy. In validation on external datasets, models for traits such as LMA and LDMC performed relatively well, while carbon fractions showed steep declines in accuracy.We provide models that produce fast, reliable estimates of several functional traits from leaf spectra. Our results reinforce the potential uses of spectroscopy in monitoring plant function around the world. [ABSTRACT FROM AUTHOR]

Summary: Trees are known to be atmospheric methane (CH4) emitters. Little is known about seasonal dynamics of tree CH4 fluxes and relationships to environmental conditions. That prevents the correct estimation of net annual tree and forest CH4 exchange.We aimed to explore the contribution of stem emissions to forest CH4 exchange. We determined seasonal CH4 fluxes of mature European beech (Fagus sylvatica) stems and adjacent soil in a typical temperate beech forest of the White Carpathians with high spatial heterogeneity in soil moisture.The beech stems were net annual CH4 sources, whereas the soil was a net CH4 sink. High CH4 emitters showed clear seasonality in their stem CH4 emissions that followed stem CO2 efflux. Elevated CH4 fluxes were detected during the vegetation season. Observed high spatial variability in stem CH4 emissions was neither explicably by soil CH4 exchange nor by CH4 concentrations, water content, or temperature studied in soil profiles near each measured tree. The stem CH4 emissions offset the soil CH4 uptake by up to 46.5% and on average by 13% on stand level.In Central Europe, widely grown beech contributes markedly to seasonal dynamics of ecosystem CH4 exchange. Its contribution should be included into forest greenhouse gas flux inventories. [ABSTRACT FROM AUTHOR]

Summary: Proteins of the DELLA family integrate environmental signals to regulate growth and development throughout the plant kingdom. Plants expressing non‐degradable DELLA proteins underpinned the development of high‐yielding 'Green Revolution' dwarf crop varieties in the 1960s. In vascular plants, DELLAs are regulated by gibberellins, diterpenoid plant hormones. How DELLA protein function has changed during land plant evolution is not fully understood.We have examined the function and interactions of DELLA proteins in the moss Physcomitrium (Physcomitrella) patens, in the sister group of vascular plants (Bryophytes).PpDELLAs do not undergo the same regulation as flowering plant DELLAs. PpDELLAs are not degraded by diterpenes, do not interact with GID1 gibberellin receptor proteins and do not participate in responses to abiotic stress. PpDELLAs do share a function with vascular plant DELLAs during reproductive development. PpDELLAs also regulate spore germination. PpDELLAs interact with moss‐specific photoreceptors although a function for PpDELLAs in light responses was not detected. PpDELLAs likely act as 'hubs' for transcriptional regulation similarly to their homologues across the plant kingdom.Taken together, these data demonstrate that PpDELLA proteins share some biological functions with DELLAs in flowering plants, but other DELLA functions and regulation evolved independently in both plant lineages. [ABSTRACT FROM AUTHOR]

Summary: The phytohormones abscisic acid (ABA) and gibberellic acid (GA) antagonistically control the shift between seed dormancy and its alleviation. DELAY OF GERMINATION1 (DOG1) is a critical regulator that determines the intensity of primary seed dormancy, but its underlying regulatory mechanism is unclear.In this study, we combined physiological, biochemical, and genetic approaches to reveal that a bHLH transcriptional factor WRKY36 progressively silenced DOG1 expression to break seed dormancy through ABI5‐BINDING PROTEIN 2 (AFP2) as the negative regulator of ABA signal.AFP2 interacted with WRKY36, which recognizes the W‐BOX in the DOG1 promoter to suppress its expression; Overexpressing WRKY36 broke primary seed dormancy, whereas wrky36 mutants showed strong primary seed dormancy. In addition, AFP2 recruited the transcriptional corepressor TOPLESS‐RELATED PROTEIN2 (TPR2) to reduce histone acetylation at the DOG1 locus, ultimately mediating WRKY36‐dependent inhibition of DOG1 expression to break primary seed dormancy.Our result proposes that the WRKY36‐AFP2‐TPR2 module progressively silences DOG1 expression epigenetically, thereby fine‐tuning primary seed dormancy. [ABSTRACT FROM AUTHOR]

Summary: Phytochrome B (phyB) expressed in the epidermis is sufficient to promote red light responses, including the inhibition of hypocotyl elongation and hypocotyl negative gravitropism. Nonetheless, the downstream mechanism of epidermal phyB in promoting light responses had been elusive.Here, we mutagenized the epidermis‐specific phyB‐expressing line (MLB) using ethyl methanesulfonate (EMS) and characterized a novel mutant allele of RRC1 (rrc1‐689), which causes reduced epidermal phyB‐mediated red light responses.The rrc1‐689 mutation increases the alternative splicing of major clock gene transcripts, including PRR7 and TOC1, disrupting the rhythmic expression of the entire clock and clock‐controlled genes. Combined with the result that MLB/prr7 exhibits the same red‐hyposensitive phenotypes as MLB/rrc1‐689, our data support that the circadian clock is required for the ability of epidermal phyB to promote light responses. We also found that, unlike phyB, RRC1 preferentially acts in the endodermis to maintain the circadian rhythm by suppressing the alternative splicing of core clock genes.Together, our results suggest that epidermal phyB requires RRC1 to promote light responses by activating the circadian rhythm in Arabidopsis thaliana. [ABSTRACT FROM AUTHOR]

Summary: Metabolites including antibiotics, enzymes, and volatiles produced by plant‐associated bacteria are key factors in plant–microbiota interaction that regulates various plant biological processes. There should be crucial mediators responsible for their entry into host plants. However, less is known about the identities of these plant transporters.We report that the Arabidopsis Nitrate Transporter1 (NRT1)/NPF protein NPF2.13 functions in plant uptake of tunicamycin (TM), a natural antibiotic produced by several Streptomyces spp., which inhibits protein N‐glycosylation. Loss of NPF2.13 function resulted in enhanced TM tolerance, whereas NPF2.13 overexpression led to TM hypersensitivity. Transport assays confirmed that NPF2.13 is a H+/TM symporter and the transport is not affected by other substrates like nitrate. NPF2.13 exclusively showed TM transport activity among tested NPFs.Tunicamycin uptake from TM‐producing Streptomyces upregulated the expression of nitrate‐related genes including NPF2.13. Moreover, nitrate allocation to younger leaves was promoted by TM in host plants. Tunicamycin could also benefit plant defense against the pathogen. Notably, the TM effects were significantly repressed in npf2.13 mutant.Overall, this study identifies NPF2.13 protein as an important TM transporter in plant–microbe interaction and provides insights into multiple facets of NPF proteins in modulating plant nutrition and defense by transporting exterior bacterial metabolites. [ABSTRACT FROM AUTHOR]

Summary: Ubiquitin‐like domain‐containing proteins (UDPs) are involved in the ubiquitin‐proteasome system because of their ability to interact with the 26S proteasome. Here, we identified potato StUDP as a target of the Phytophthora infestans RXLR effector Pi06432 (PITG_06432), which supresses the salicylic acid (SA)‐related immune pathway.By overexpressing and silencing of StUDP in potato, we show that StUDP negatively regulates plant immunity against P. infestans. StUDP interacts with, and destabilizes, the 26S proteasome subunit that is referred to as REGULATORY PARTICLE TRIPLE‐A ATP‐ASE (RPT) subunit StRPT3b. This destabilization represses the proteasome activity. Proteomic analysis and Western blotting show that StUDP decreases the stability of the master transcription factor SYSTEMIC ACQUIRED RESISTANCE DEFICIENT 1 (SARD1) in SA biosynthesis.StUDP negatively regulates the SA signalling pathway by repressing the proteasome activity and destabilizing StSARD1, leading to a decreased expression of the SARD1‐targeted gene ISOCHORISMATE SYNTHASE 1 and thereby a decrease in SA content. Pi06432 stabilizes StUDP, and it depends on StUDP to destabilize StRPT3b and thereby supress the proteasome activity.Our study reveals that the P. infestans effector Pi06432 targets StUDP to hamper the homeostasis of the proteasome by the degradation of the proteasome subunit StRPT3b and thereby suppresses SA‐related immunity. [ABSTRACT FROM AUTHOR]

Summary: Flavonoids are important plant pigments and defense compounds; understanding the transcriptional regulation of flavonoid biosynthesis may enable engineering crops with improved nutrition and stress tolerance. Here, we characterize R2R3‐MYB domain subgroup 7 transcription factor CaMYB39, which regulates flavonol biosynthesis primarily in chickpea trichomes.CaMYB39 overexpression in chickpea was accompanied by a change in flux availability for the phenylpropanoid pathway, particularly flavonol biosynthesis. Lines overexpressing CaMYB39 showed higher isoflavonoid levels, suggesting its role in regulating isoflavonoid pathway. CaMYB39 transactivates the transcription of early flavonoid biosynthetic genes (EBG). FLAVONOL SYNTHASE2, an EBG, encodes an enzyme with higher substrate specificity for dihydrokaempferol than other dihydroflavonols explaining the preferential accumulation of kaempferol derivatives as prominent flavonols in chickpea.Interestingly, CaMYB39 overexpression increased trichome density and enhanced the accumulation of diverse flavonol derivatives in trichome‐rich tissues. Moreover, CaMYB39 overexpression reduced reactive oxygen species levels and induced defense gene expression which aids in partially blocking the penetration efficiency of the fungal pathogen, Ascochyta rabiei, resulting in lesser symptoms, thus establishing its role against deadly Ascochyta blight (AB) disease.Overall, our study reports an instance where R2R3‐MYB‐SG7 member, CaMYB39, besides regulating flavonol biosynthesis, modulates diverse pathways like general phenylpropanoid, isoflavonoid, trichome density, and defense against necrotrophic fungal infection in chickpea. [ABSTRACT FROM AUTHOR]

Summary: SUMOylation as one of the protein post‐translational modifications plays crucial roles in multiple biological processes of eukaryotic organisms. Botrytis cinerea is a devastating fungal pathogen and capable of infecting plant hosts at low temperature. However, the molecular mechanisms of low‐temperature adaptation are largely unknown in fungi.Combining with biochemical methods and biological analyses, we report that SUMOylation regulates pathogen survival at low temperature and oxidative DNA damage response during infection in B. cinerea. The heat shock protein (Hsp70) BcSsb and E3 ubiquitin ligase BcRad18 were identified as substrates of SUMOylation; moreover, their SUMOylation both requires a single unique SUMO‐interacting motif (SIM).SUMOylated BcSsb regulates β‐tubulin accumulation, thereby affecting the stability of microtubules and consequently mycelial growth at low temperature. On the contrary, SUMOylated BcRad18 modulates mono‐ubiquitination of the sliding clamp protein proliferating cell nuclear antigen (PCNA), which is involved in response to oxidative DNA damage during infection.Our study uncovers the molecular mechanisms of SUMOylation‐mediated low‐temperature survival and oxidative DNA damage tolerance during infection in a devastating fungal pathogen, which provides novel insights into low‐temperature adaptation and pathogenesis for postharvest pathogens as well as new targets for inhibitor invention in disease control. [ABSTRACT FROM AUTHOR]

Summary: Ectomycorrhizal (EcM) fungi play a crucial role in the mineral nitrogen (N) nutrition of their host trees. While it has been proposed that several EcM species also mobilize organic N, studies reporting the EcM ability to degrade N‐containing polymers, such as chitin, remain scarce.Here, we assessed the capacity of a representative collection of 16 EcM species to acquire 15N from 15N‐chitin. In addition, we combined genomics and transcriptomics to identify pathways involved in exogenous chitin degradation between these fungal strains.Boletus edulis, Imleria badia, Suillus luteus, and Hebeloma cylindrosporum efficiently mobilized N from exogenous chitin. EcM genomes primarily contained genes encoding for the direct hydrolysis of chitin. Further, we found a significant relationship between the capacity of EcM fungi to assimilate organic N from chitin and their genomic and transcriptomic potentials for chitin degradation.These findings demonstrate that certain EcM fungal species depolymerize chitin using hydrolytic mechanisms and that endochitinases, but not exochitinases, represent the enzymatic bottleneck of chitin degradation. Finally, this study shows that the degradation of exogenous chitin by EcM fungi might be a key functional trait of nutrient cycling in forests dominated by EcM fungi. [ABSTRACT FROM AUTHOR]

Summary: Genetic divergence between species depends on reproductive isolation (RI) due to traits that reduce interspecific mating (prezygotic isolation) or are due to reduced hybrid fitness (postzygotic isolation). Previous research found that prezygotic barriers tend to be stronger than postzygotic barriers, but most studies are based on the evaluation of F1 hybrid fitness in early life cycle stages.We combined field and experimental data to determine the strength of 17 prezygotic and postzygotic reproductive barriers between two Lysimachia species that often co‐occur and share pollinators. We assessed postzygotic barriers up to F2 hybrids and backcrosses.The two species showed near complete RI due to the cumulative effect of multiple barriers, with an uneven and asymmetric contribution to isolation. In allopatry, prezygotic barriers contributed more to reduce gene flow than postzygotic barriers, but their contributions were more similar in sympatry.The strength of postzygotic RI was up to three times lower for F1 progeny than for F2 or backcrossed progenies, and RI was only complete when late F1 stages and either F2 or backcrosses were accounted for. Our results thus suggest that the relative strength of postzygotic RI may be underestimated when its effects on late stages of the life cycle are disregarded. [ABSTRACT FROM AUTHOR]

This article is a Commentary on Shao et al. (2023), 238: 80–95. [ABSTRACT FROM AUTHOR]

This article is a Commentary on Debra‐Maceluch et al. (2023), 238: 297–312. [ABSTRACT FROM AUTHOR]

Summary: Although leaves are considered the main site for photosynthesis, other green nonfoliar tissues can carry out considerable amounts of photosynthetic carbon assimilation. With photosynthesis, a potential target for improving crop productivity, physiology and contribution of nonfoliar tissues to overall plant carbon acquisition is gaining increasing attention. This review will provide an overview of nonfoliar photosynthesis, the role of stomata in these tissues and methodologies for quantification and the contribution to overall carbon gain. [ABSTRACT FROM AUTHOR]

Summary: Root lodging poses a major threat to maize production, resulting in reduced grain yield and quality, and increased harvest costs.Here, we combined expressional, genetic, and cytological studies to demonstrate a role of ZmYUC2 and ZmYUC4 in regulating gravitropic response of the brace root and lodging resistance in maize.We show that both ZmYUC2 and ZmYUC4 are preferentially expressed in root tips with partially overlapping expression patterns, and the protein products of ZmYUC2 and ZmYUC4 are localized in the cytoplasm and endoplasmic reticulum, respectively. The Zmyuc4 single mutant and Zmyuc2/4 double mutant exhibit enlarged brace root angle compared with the wild‐type plants, with larger brace root angle being observed in the Zmyuc2/4 double mutant. Consistently, the brace root tips of the Zmyuc4 single mutant and Zmyuc2/4 double mutant accumulate less auxin and are defective in proper reallocation of auxin in response to gravi‐stimuli. Furthermore, we show that the Zmyuc4 single mutant and the Zmyuc2/4 double mutant display obviously enhanced root lodging resistance.Our combined results demonstrate that ZmYUC2‐ and ZmYUC4‐mediated local auxin biosynthesis is required for normal gravity response of the brace roots and provide effective targets for breeding root lodging resistant maize cultivars. [ABSTRACT FROM AUTHOR]

Summary: Root hairs (RH) are excellent model systems for studying cell size and polarity since they elongate several hundred‐fold their original size. Their tip growth is determined both by intrinsic and environmental signals. Although nutrient availability and temperature are key factors for a sustained plant growth, the molecular mechanisms underlying their sensing and downstream signaling pathways remain unclear.We use genetics to address the roles of the cell surface receptor kinase FERONIA (FER) and the nutrient sensing TOR Complex 1 (TORC) in RH growth.We identified that low temperature (10°C) triggers a strong RH elongation response in Arabidopsis thaliana involving FER and TORC. We found that FER is required to perceive limited nutrient availability caused by low temperature. FERONIA interacts with and activates TORC‐downstream components to trigger RH growth. In addition, the small GTPase Rho of plants 2 (ROP2) is also involved in this RH growth response linking FER and TOR. We also found that limited nitrogen nutrient availability can mimic the RH growth response at 10°C in a NRT1.1‐dependent manner.These results uncover a molecular mechanism by which a central hub composed by FER‐ROP2‐TORC is involved in the control of RH elongation under low temperature and nitrogen deficiency. [ABSTRACT FROM AUTHOR]

Summary: As the seed precursor, the ovule produces the female gametophyte (or embryo sac), and the subsequent double fertilization occurs in it. The integuments emerge sequentially from the integument primordia at the early stages of ovule development and finally enwrap the embryo sac gradually during gametogenesis, protecting and nursing the embryo sac. However, the mechanisms regulating integument development are still obscure.In this study, we show that SOMATIC EMBRYOGENESIS RECEPTOR‐LIKE KINASES (SERKs) play essential roles during integument development in Arabidopsis thaliana. The serk1/2/3 triple mutant shows arrested integuments and abnormal embryo sacs, similar defects also found in the triple loss‐of‐function mutants of ERECTA family (ERf) genes. Ovules of serk1/2/3 er erl1/2 show defects similar to er erl1/2 and serk1/2/3.Results of yeast two‐hybrid analyses, bimolecular fluorescence complementation (BiFC) analyses, and co‐immunoprecipitation assays demonstrated that SERKs interact with ERf, which depends on EPIDERMAL PATTERNING FACTOR‐LIKE (EPFL) family small peptides. The sextuple mutant epfl1/2/3/4/5/6 shows integument defects similar to both of er erl1/2 and serk1/2/3.Our results demonstrate that ERf–SERK‐mediated EPFL signaling orchestrates the development of the female gametophyte and the surrounding sporophytic integuments. [ABSTRACT FROM AUTHOR]

Summary: Arginine decarboxylase (ADC)‐mediated putrescine (Put) biosynthesis plays an important role in plant abiotic stress response. SNF1‐related protein kinases 2s (SnRK2s) and abscisic acid (ABA)‐response element (ABRE)‐binding factors (ABFs), are core components of the ABA signaling pathway involved in drought stress response. We previously reported that ADC of Poncirus trifoliata (PtrADC) functions in drought tolerance. However, whether and how SnRK2 and ABF regulate PtrADC to modulate putrescine accumulation under drought stress remains largely unclear.Herein, we employed a set of physiological, biochemical, and molecular approaches to reveal that a protein complex composed of PtrSnRK2.4 and PtrABF2 modulates putrescine biosynthesis and drought tolerance by directly regulating PtrADC.PtrABF2 was upregulated by dehydration in an ABA‐dependent manner. PtrABF2 activated PtrADC expression by directly and specifically binding to the ABRE core sequence within its promoter and positively regulated drought tolerance via modulating putrescine accumulation. PtrSnRK2.4 interacts with and phosphorylates PtrABF2 at Ser93. PtrSnRK2.4‐mediated PtrABF2 phosphorylation is essential for the transcriptional regulation of PtrADC. Besides, PtrSnRK2.4 was shown to play a positive role in drought tolerance by facilitating putrescine synthesis.Taken together, this study sheds new light on the regulatory module SnRK2.4‐ABF2‐ADC responsible for fine‐tuning putrescine accumulation under drought stress, which advances our understanding on transcriptional regulation of putrescine synthesis. [ABSTRACT FROM AUTHOR]

Summary: Although xylem embolism is a key process during drought‐induced tree mortality, its relationship to wood anatomy remains debated. While the functional link between bordered pits and embolism resistance is known, there is no direct, mechanistic explanation for the traditional assumption that wider vessels are more vulnerable than narrow ones.We used data from 20 temperate broad‐leaved tree species to study the inter‐ and intraspecific relationship of water potential at 50% loss of conductivity (P50) with hydraulically weighted vessel diameter (Dh) and tested its link to pit membrane thickness (TPM) and specific conductivity (Ks) on species level.Embolism‐resistant species had thick pit membranes and narrow vessels. While Dh was weakly associated with TPM, the P50–Dh relationship remained highly significant after accounting for TPM. The interspecific pattern between P50 and Dh was mirrored by a link between P50 and Ks, but there was no evidence for an intraspecific relationship.Our results provide robust evidence for an interspecific P50–Dh relationship across our species. As a potential cause for the inconsistencies in published P50–Dh relationships, our analysis suggests differences in the range of trait values covered, and the level of data aggregation (species, tree or sample level) studied. [ABSTRACT FROM AUTHOR]