Gene duplication is a powerful source of biological innovation giving rise to paralogous genes that undergo diverse fates. Redundancy between paralogous genes is an intriguing outcome of duplicate gene evolution, and its maintenance over evolutionary time has long been considered a paradox. Redundancy can also be dubbed ‘a geneticist's nightmare’: It hinders the predictability of genome editing outcomes

Nitrogen (N) and phosphorus (P) are the most important macronutrients required for plant growth and development. To cope with the limited and uneven distribution of N and P in complicated soil environments, plants have evolved intricate molecular strategies to improve nutrient acquisition that involve adaptive root development, production of root exudates, and the assistance of microbes. Recently,

Leaves are the main photosynthetic organs in plants, and their anatomy is optimized for light interception and gas exchange. Although each species has a characteristic leaf anatomy, which depends on the genotype, leaves also show a large degree of developmental plasticity. Light and temperature regulate leaf development from primordia differentiation to late stages of blade expansion. While the molecular

Introduction Nitrogen (N) is a fundamental nutrient for all living organisms and can limit plant productivity and impact food security around the globe (Elser et al., 2007; Gruber & Galloway, 2008). At the same time, excess N inputs into the biosphere through anthropogenic activities lead to environmental problems including the eutrophication of drinking water and the emission of greenhouse gases (Schlesinger

Introduction The flux of water from the terrestrial landscape to the atmosphere fundamentally influences the Earth's energy budget and hydrological cycle and is mediated by its pathway through vegetation. Over short timescales, vegetation controls water vapour fluxes by varying stomatal conductance, but over greater temporal and spatial scales, fluxes are determined by vegetation community composition

Introduction Trait-based plant ecology assumes that plant attributes, that is, functional traits, mediate community assembly and ecosystem processes (Violle et al., 2007; Shipley et al., 2016). Traditionally, this discipline focused on mean differences between species' traits (i.e. interspecific trait variation) to address ecological questions related, for example, to plant coexistence or niche differentiation

There is mounting evidence that organismal eco-evolutionary responses to climate change will meaningfully impact ecosystem structure and function (Rietl et al., 2021; Rastetter et al., 2022). One research gap that limits our ability to incorporate these processes into ecosystem projections is the uncertain role of phenotypic plasticity in evolutionary change. Although this research gap was identified

Introduction Forests are large and persistent sinks for atmospheric carbon dioxide (CO2; Pan et al., 2011) and large-scale afforestation and reforestation have been suggested as methods for mitigating climate change through carbon sequestration (Law et al., 2018; Nave et al., 2018; Bastin et al., 2019; Pugh et al., 2019; Domke et al., 2020). However, intensification of forestry (Kastner et al., 2021)

Introduction It is well known that large vessels in xylem are more efficient for conducting xylem sap than narrow ones considering the Hagen–Poiseuille equation (Sperry et al., 2005). Yet, there is no clear evidence whether large vessels consistently embolize before the narrow ones (Isasa et al., 2023). Intervessel pits, which interconnect the walls of adjacent vessels (also called ‘end walls’), have

Introduction Bread wheat (Triticum aestivum) is one of our major food commodities, with a global production rate close to 1 billion tonnes per year and a world trade greater than any other crops (FAOSTAT, http://www.fao.org/faostat). The high yield performance of today's wheats greatly relies on their semidwarf stature, whereby the reduced stem elongation is associated with an improved resistance to

Ectomycorrhizal symbiosis between roots and fungi is founded on the movement of carbon from plants to fungi, and of soil resources from fungi to plants. Framing this movement as a trade can facilitate an understanding of how this mutualism has developed over evolutionary time, but fails to explain experimental observations of carbon and nutrient movement. Here, I propose that source–sink dynamics are

Introduction The ‘fast – slow axis’ of the leaf economics spectrum is a major structuring principle in ecology (Wardle, 2004; Reich, 2014). Plant species on the ‘fast’ side of the gradient are characterized by high relative growth rates, high specific leaf area, high relative nitrogen content and photosynthesis rate, whereas resource-conservative ‘slow’ plant species show opposite patterns (Wright

Introduction The potential for hydrogen (H) and oxygen (O) isotope analysis of plant cellulose to yield inferences about past climates and physiological processes has long been recognised (Schiegl & Vogel, 1970; Epstein et al., 1976; Gray & Thompson, 1976; Libby et al., 1976). However, despite its research history, substantial uncertainty remains around the exact biological and environmental information

Introduction Plants have a lifelong interaction with a complex and diverse microbial community that inhabits both their underground and aboveground organs, which is collectively called the plant microbiota. Plant-associated microbial communities can support the growth of their host by supplying nutrients, increasing tolerance to both biotic and abiotic stresses (Hiruma et al., 2016; Almario et al.

Introduction Pollen and tracheophyte spores are ubiquitous in the environment and present in air, soil and sediments. Accurate classification and quantification of pollen grains is critical for a range of palynological applications (Edwards et al., 2017) including the forecasting of aeroallergens, melissopalynology and forensics. Fossil pollen preserved in sedimentary archives is a powerful proxy used

Introduction Biological soil crusts (biocrusts) are photoautotroph-dominated soil surface communities dwelling in many low-productivity ecosystems such as drylands and cover c. 12% of the terrestrial surface (Rodriguez-Caballero et al., 2018). These surface communities provide multiple critical ecosystem functions such as stabilizing the surface of bare soil, retaining soil moisture, and capturing

Although intrinsic postzygotic reproductive barriers can play a fundamental role in speciation, their underlying evolutionary causes are widely debated. One hypothesis is that incompatibilities result from genomic conflicts. Here, I synthesize the evidence that conflict generates incompatibilities in plants, thus playing a creative role in plant biodiversity. While much evidence supports a role for

Introduction Pseudomonads are ubiquitous bacteria of the phyllosphere, the aboveground portion of plants whose main component is the leaves (Vorholt, 2012; Almario et al., 2022). There, Pseudomonas can play a wide range of roles, from serious pathogens to biocontrol agents (Hirano & Upper, 2000; Legein et al., 2020). Pseudomonas viridiflava is a widespread opportunistic pathogen of plants (Wilkie et al

The formation of inflorescences and flowers is essential for the successful reproduction of angiosperms. In the past few decades, genetic studies have identified the LEAFY transcription factor and the UNUSUAL FLORAL ORGANS (UFO) F-box protein as two major regulators of flower development in a broad range of angiosperm species. Recent research has revealed that UFO acts as a transcriptional cofactor

Corrigendum to New Phytologist 234 (2022), 1394–1410, doi: 10.1111/nph.18064. Since its publication, the authors of Sonawane et al. (2022) have identified an error in the author affiliations listed in the article. The author Ashok P. Giri was listed in the original article as being associated with affiliations 2 and 3 noted above. This correction serves to amend this to the following affiliations (correct

Plant evolution has been characterised by a series of major novelties in their vegetative and reproductive traits that have led to greater complexity. Underpinning this diversification has been the evolution of the genome. When viewed at the scale of the plant kingdom, plant genome evolution has been punctuated by conspicuous instances of gene and whole-genome duplication, horizontal gene transfer

Introduction Drylands cover c. 40% of the Earth's terrestrial surface and support the livelihoods of c. 40% of the world's human population (Millennium Ecosystem Assessment, 2005). However, c. 20% of global drylands have experienced some form of severe land degradation, which directly/indirectly poses threats to millions of people (Reynolds et al., 2007). A widely observed form of ecosystem degradation

Introduction Soybean, like other legumes, can establish symbiosis with soil-borne rhizobia (Bergersen & Turner, 1967). Soybean nodulation begins with isoflavone secretion from the root hair to attract rhizobia to the root (Redmond et al., 1986; Caetano-Anollés et al., 1991; Ferguson et al., 2019) and activates the biosynthesis of nod factors (NFs) in rhizobia (Schultze & Kondorosi, 1998). NFs are perceived

Introduction All animals and plants are colonized by microorganisms (Gilbert & Neufeld, 2014). As one of the most common types of biotic interactions, plant–microbial symbioses are essential for plant fitness, ecosystem functioning and biogeochemical cycling (Berendsen et al., 2012; Liu et al., 2020). However, our knowledge about plant–microbial symbioses is highly variable among symbiosis types, with

Rhodophyta (or red algae) are a diverse and species-rich group that forms one of three major lineages in the Archaeplastida, a eukaryotic supergroup whose plastids arose from a single primary endosymbiosis. Red algae are united by several features, such as relatively small intron-poor genomes and a lack of cytoskeletal structures associated with motility like flagella and centrioles, as well as a highly

Introduction The colonisation of land by plants is one of the most important events in the history of our planet. These plants and their descendants shaped all subsequent land ecosystems, forming the basis for terrestrial primary productivity (Kenrick et al., 2012) and likely altering global sedimentation patterns, biogeochemical cycling and perhaps oxygenation levels (Algeo & Scheckler, 1998; Gibling

Introduction Nitrogen (N) is often limiting for crop growth since it is a key component of proteins, nucleic acids, chlorophylls, and many other molecules of primary and secondary metabolism (Hodges, 2002). Globally, agriculture uses 111 Tg N fertilizer yearly to support crop production and food security (FAO, 2019). Over application of N fertilizer results in N leaching into water bodies, and production

Introduction Mountain regions cover only a quarter of the Earth's land surface but harbour a considerable proportion of its terrestrial biodiversity across different taxa (Körner, 2000; Rahbek et al., 2019b). Different biogeographic principles have been proposed to explain the high biodiversity within mountains (Spehn & Körner, 2005), with habitat heterogeneity being one of the most prominent drivers

Stomatal pores in leaves control CO2 entry for photosynthesis and water loss via transpiration. Stomata open in response to light, low CO2 levels and high air humidity, and close in response to darkness, elevated CO2 concentration, low air and soil humidity. Stomatal closure responses are largely mediated by the stress hormone abscisic acid (ABA) which is produced in response to drought and reduced

Plants must contend with a diversity of antagonistic organisms that continuously threaten their survival. These complex interactions have led to a variety of direct and indirect plant defense strategies that protect plant tissues from consumption by insects and pathogens (Whitehill et al., 2023). Since Gottifred Fraenkel catalyzed interest in plant chemical defenses in 1959 with the publication ‘The

Introduction Water availability controls evapotranspiration (ET) over most of the vegetated land surface (Beer et al., 2010; Schwalm et al., 2010; Seneviratne et al., 2010; Ahlström et al., 2015). As droughts may become more severe and frequent in the future (Seneviratne et al., 2021), it is crucial to understand how plant function links ecosystem ET and water limitation. Quantifying water limitation

This article is a Commentary on Blume-Werry et al. (2023), 240: 502–514.

Introduction DNA sequence polymorphism is the ultimate source of variation in evolution. Variation in the processes underlying divergent levels of sequence polymorphism (selection, mutation rate) between genes also plays a central role in the evolutionary dynamics of gene duplicates (Panchy et al., 2016). Following gene duplication, relaxed or positive selection on one or both paralogs promotes mutation

The functional link between cell-surface receptors and intracellular NLR immune receptors is a critical aspect of plant immunity. To establish disease, successful pathogens have evolved mechanisms to suppress cell-surface immune signalling. In response, plants have adapted by evolving NLRs that recognize pathogen effectors involved in this suppression, thereby counteracting their immune-suppressing

Chromosome number is a definitive eukaryotic trait, the evolution of which reflects fundamental changes to an organism's genomic architecture. Chromosome number varies nearly 3000-fold among green plant species, frequently evolving through whole-genome duplication (WGD), aneuploidy following the loss or duplication of individual chromosomes, and dysploidy following chromosome fission or fusion. Accordingly

Introduction Lowland tropical rainforests make up the most productive terrestrial biome and cover nearly 10% of Earth's land surface (Saatchi et al., 2011). As such, they represent a key component of the models predicting Earth's capacity to combat increasing levels of CO2 (Bonan & Levis, 2010; Huntingford et al., 2013). Yet the nature and extent to which climate and nutrient availability influence

Introduction A germinating seed buried under soil displays skotomorphogenic growth characterized by fast growing hypocotyls, closed cotyledons, and a protective apical hook until light is reached. Upon exposure to light, the seedling initiates photomorphogenic development by hypocotyl elongation inhibition, cotyledon expansion, and development of functional chloroplasts in order to start performing

Introduction Sudden cell rupture when the primary vasculature is severed by feeding herbivores triggers the production of electrical signals called slow-wave potentials (SWPs; Stahlberg et al., 2006; Kurenda et al., 2019). In Arabidopsis, these signals are propagated from leaf to leaf at apparent velocities of c. 8 centimetres per minute to initiate the synthesis of jasmonates (Mousavi et al., 2013)

Introduction Alternative splicing (AS) is a mechanism by which cells generate abundant protein diversity from a limited number of genes (Baralle & Giudice, 2017). AS plays a crucial role in regulating various life activities such as growth, development, and aging in plants (Zhu et al., 2017; Godoy Herz & Kornblihtt, 2019; Jabre et al., 2019; Chen et al., 2020; Reddy et al., 2020; Zhang et al., 2020)

Plant species new to science are described at a rate of c. 2000 per year (Cheek et al., 2020). This rate has remained constant for decades, suggesting that there are still tens of thousands of species currently unknown to science – some estimates suggest that over 20% of plant species (up to 100 000) are yet to be discovered (Pimm & Joppa, 2015; Corlett, 2016; Heywood, 2017). Recently described plants

Introduction Temperate and boreal forests play important roles in regulating global carbon cycle dynamics due to their large spatial coverage (Bradshaw & Warkentin, 2015), their exposure to amplified rates of global warming (Holland & Bitz, 2003; Rantanen et al., 2022), and the large magnitude of the carbon stocks in northern ecosystems (Thurner et al., 2014; Yang et al., 2020). Rapidly increasing

Introduction The origin of land plants with the adaptation of a charophyte algal ancestor to a terrestrial habitat was a major event in the history of the Earth, enabling subsequent terrestrialisation events in the animal lineage and the establishment of complex ecosystems on land (Bowman, 2022). Fossil evidence around this event is sparse (reviewed in Bowman, 2022); so much is unknown about the early

This article is a Commentary on Yang et al. (2023), 240: 694–709.

Introduction The accumulation of knowledge on biodiversity is fundamental to document, classify, and ultimately understand its patterns and processes across space and through time (Soberón & Peterson, 2004). In recent years, digital accessible knowledge (Sousa-Baena et al., 2014; Miller et al., 2020) has stood at the forefront of biodiversity research, providing a multifaceted array of easily accessible

Introduction Plants have complex immune systems to fend off pathogen infections (Jones & Dangl, 2006). Membrane-localized pattern recognition receptors (PRRs) recognize diverse molecular patterns generated from microbial activities to elicit pattern-triggered immunity (PTI; Monaghan & Zipfel, 2012; Bigeard et al., 2015). By comparison, effector-triggered immunity (ETI) is mediated by the intracellular

Introduction Phenotypic plasticity, and its inverse – robustness – are attributes of development in all organisms. When plasticity or robustness in a given trait is most beneficial for fitness depends on the degree of environmental variability, reliability in environmental cues and the costs associated with phenotypic adjustment (Fischer et al., 2014). Although there are many examples of adaptive plasticity

Introduction Plants regulate germination and development at various stages to ensure the best success under challenging conditions (Nicotra et al., 2010; Lee et al., 2012; Kaiserli et al., 2018). When young seedlings perceive abiotic stress such as drought or salinity, they halt the extension of radicles and the development of cotyledons (Jakab et al., 2005; Cutler et al., 2010; Daszkowska-Golec, 2011)

This article is a Commentary on Stephens et al. (2023), 240: 880–891.

The development of insecticidal chemicals (commonly termed pesticides) has revolutionized the process of cultivation in agriculture, yet similarly to the development of antimicrobial resistance in pathogens, insects can rapidly develop resistance to these chemicals (Alyokhin & Chen, 2017). Pesticides can also negatively affect beneficial insects such as pollinators and natural enemies of herbivorous

In addition to promoting host plant mineral nutrition, arbuscular mycorrhizal fungi (AMF) improve tolerance to multiple abiotic stresses (Lenoir et al., 2016). Among stresses that impact ecosystem stability and agricultural production, resistance and recovery from drought are challenges that plants in changing climates will increasingly face. Drought stress also causes nutritional stress since soluble

Introduction Viable pollen is critical for successful fertilization in the plant. The tapetum is the innermost layer of the anther wall, which directly communicates with developing pollen grains, and finally degenerates at the mature pollen grain stage. It is involved in the production of the enzymes for releasing microspores from the tetrads and providing essential nutrients for pollen wall and coat

Introduction Sterols and steroids, which are produced in most organisms, are important for controlling membrane fluidity. Chemically, steroids are tetracyclic triterpenoids with a sterane skeleton (Fig. 1a, e.g. dehydroepiandrosterone, DHEA, in Fig. 1b). Fig. 1 Open in figure viewerPowerPoint Structure and numbering of carbon atoms in the sterane skeleton of steroids. The figure depicts the sterane

Introduction Reactive oxygen species (ROS) and major redox buffers, namely ascorbate (ASC), glutathione (GSH) and pyridine nucleotides (NAD(H) and NADP(H)) are key partners in orchestrating the redox poise in developing cells (Considine & Foyer, 2021). The ascorbate–glutathione (ASC–GSH) cycle links those redox buffers together in a ménage-à-trois allowing rapid ROS processing while controlling the

Introduction Many marine microorganisms are capable of adhering to surfaces underwater where they form taxonomically diverse, often photosynthetically active biofilm communities embedded in a three-dimensional (3D) matrix of self-produced extracellular polymeric substances (EPS). In fact biofilms are the most abundant microbial lifestyle on the planet, accounting for c. 80% of all bacterial cells (Flemming

Introduction In sexual organisms, meiosis and gametic union typically pattern life cycles into alternating diploid and haploid phases (Bowman et al., 2016; Pandey et al., 2022). In green algae and land plants, they consist in the sporophytic and gametophytic generations, each operating specific programs for establishing the reproductive lineages. During sporogenesis, diploid sporophytic cells are specified

Introduction Phosphorous (P), a component of nucleic acids, phospholipids and numerous intermediary metabolites, is essential for growth and development. Plants preferentially acquire P in the form of inorganic phosphate (Pi, mainly orthophosphate) from the rhizosphere, where Pi is often fixed in the soil and becomes unavailable (Raghothama, 1999). To cope with Pi limitation, plants have evolved intricate

Introduction Cytoplasmic male sterility and Restorer-of-fertility genes Cytoplasmic male sterility (CMS), a mitochondrially encoded trait that leads to a failure of the plant to produce fertile pollen, can spontaneously arise in natural plant populations or be generated artificially through interspecific crosses or protoplast fusions (Kaul, 1988; Chase, 2007). As CMS requires the affected plant to

This article is a Commentary on Li et al. (2023), 240: 285–301.