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The Chilean soapbark tree (Quillaja saponaria) produces soap-like molecules called QS saponins that are important vaccine adjuvants. These highly valuable compounds are sourced by extraction from the bark, and their biosynthetic pathway is unknown. Here, we sequenced the Q. saponaria genome. Through genome mining and combinatorial expression in tobacco, we identified 16 pathway enzymes that together enable the production of advanced QS pathway intermediates that represent a bridgehead for adjuvant bioengineering. We further identified the enzymes needed to make QS-7, a saponin with excellent therapeutic properties and low toxicity that is present in low abundance in Q. saponaria bark extract. Our results enable the production of Q. saponaria vaccine adjuvants in tobacco and open the way for new routes to access and engineer natural and new-to-nature immunostimulants.
Via Loïc Lepiniec
Plants confront multifarious environmental stresses widely divided into abiotic and biotic stresses, of which heavy metal stress represents one of the most damaging abiotic stresses. Heavy metals cause toxicity by targeting crucial molecules and vital processes in the plant cell. One of the approaches by which heavy metals act in plants is by over production of reactive oxygen species (ROS) either directly or indirectly. Plants act against such overdose of metal in the environment by boosting the defense responses like metal chelation, sequestration into vacuole, regulation of metal intake by transporters, and intensification of antioxidative mechanisms. This response shown by plants is the result of intricate signaling networks functioning in the cell in order to transmit the extracellular stimuli into an intracellular response. The crucial signaling components involved are calcium signaling, hormone signaling, and mitogen activated protein kinase (MAPK) signaling that are discussed in this review. Apart from signaling components other regulators like microRNAs and transcription factors also have a major contribution in regulating heavy metal stress. This review demonstrates the key role of MAPKs in synchronously controlling the other signaling components and regulators in metal stress. Further, attempts have been made to focus on metal transporters and chelators that are regulated by MAPK signaling.
Transcriptomic analyses with high temporal resolution provide substantial new insight into hormonal response networks. This study identified the kinetics of genome-wide transcript abundance changes in response to elevated levels of the plant hormone ethylene in roots from light-grown Arabidopsis ( Arabidopsis thaliana ) seedlings, which were overlaid on time-matched developmental changes. Functional annotation of clusters of transcripts with similar temporal patterns revealed rapidly induced clusters with known ethylene function and more slowly regulated clusters with novel predicted functions linked to root development. In contrast to studies with dark-grown seedlings, where the canonical ethylene response transcription factor, EIN3, is central to ethylene-mediated development, the roots of ein3 and eil1 single and double mutants still respond to ethylene in light-grown seedlings. Additionally, a subset of these clusters of ethylene-responsive transcripts were enriched in targets of EIN3 and ERFs. These results are consistent with EIN3-independent developmental and transcriptional changes in light-grown roots. Examination of single and multiple gain-of-function and loss-of-function receptor mutants revealed that, of the five ethylene receptors, ETR1 controls lateral root and root hair initiation and elongation and the synthesis of other receptors. These results provide new insight into the transcriptional and developmental responses to ethylene in light-grown seedlings.
Light is the energy source for plants as it drives photosynthesis to produce sugars. Given the obvious fact that light mostly occurs above ground and not in the soil, most interactions of plants with light have been studied in shoot parts of the plant. Research over more than a century has yielded tremendous insights into how light not only drives photosynthesis but also acts as an environmental cue that informs plants about their environment. Light quality and duration, for example, drive major developmental changes such as photomorphogenesis, photoperiodic induction of flowering, phototropism, and shade avoidance (see, for example, the following recent reviews: Wu, 2014; Fankhauser and Christie, 2015; Xu et al., 2015; Ballaré and Pierik, 2017). The picture that has emerged is that plants have very detailed light signaling mechanisms, with photoreceptors dedicated to different wavelengths in the light spectrum and interactions between these photoreceptors themselves and their downstream signal transduction pathways. Studies have accumulated over the past 15 years, and intensified in recent years, showing pronounced effects of light on root physiology and development. Although some effects of light availability on root growth will be the simple consequence of differential sugar availability to the roots due to photosynthesis in the shoot, there is substantial evidence for more sophisticated signaling impacts of different aspects of the light environment. In this Update, we will briefly review the core light signaling mechanisms, their impact on root development and plasticity, and the functional implications of these aboveground-belowground interactions.
Ripening is one of the key processes associated with the development of major organoleptic characteristics of the fruit. This process has been extensively characterized in climacteric fruit, in contrast with non-climacteric fruit such as grape, where the process is less understood. With the aim of studying changes in gene expression during ripening of non-climacteric fruit, an Illumina based RNA-Seq transcriptome analysis was performed on four developmental stages, between veraison and harvest, on table grapes berries cv Thompson Seedless. Functional analysis showed a transcriptional increase in genes related with degradation processes of chlorophyll, lipids, macromolecules recycling and nucleosomes organization; accompanied by a decrease in genes related with chloroplasts integrity and amino acid synthesis pathways. It was possible to identify several processes described during leaf senescence, particularly close to harvest. Before this point, the results suggest a high transcriptional activity associated with the regulation of gene expression, cytoskeletal organization and cell wall metabolism, which can be related to growth of berries and firmness loss characteristic to this stage of development. This high metabolic activity could be associated with an increase in the transcription of genes related with glycolysis and respiration, unexpected for a non-climacteric fruit ripening.
Betalains are tyrosine-derived red-violet and yellow pigments found exclusively in plants of the Caryophyllales order, which have drawn both scientific and economic interest. Nevertheless, research into betalain chemistry, biochemistry, and function has been limited as comparison with other major classes of plant pigments such as anthocyanins and carotenoids. The core biosynthetic pathway of this pigment class has only been fully elucidated in the past few years, opening up the possibility for betalain pigment engineering in plants and microbes. In this review, we discuss betalain metabolism in light of recent advances in the field, with a current survey of characterized genes and enzymes that take part in betalain biosynthesis, catabolism, and transcriptional regulation, and an outlook of what is yet to be discovered. A broad view of currently used and potential new sources for betalains, including utilization of natural sources or metabolic engineering, is provided together with a summary of potential applications of betalains in research and commercial use.
Auxin research touches on a very wide variety of processes in plant development, and correspondingly a range of systems and approaches is revealing new understanding. This special issue spans this range, from research on mosses and liverworts which is revealing evolutionary aspects to the exquisite detail of signalling processes shown in Arabidopsis and agronomic potential in crops. As well as compiling and analyzing our current knowledge on auxin action, the reviews also provide a roadmap for future research.
The development and judicious use of agricultural biotechnology offers important contributions to food security and sustainability. Key contributions include improved yield, heightened pathogen and herbivore resistance, enhanced nutrient content, improved product quality, reduced spoilage, as well as entirely new traits. While a first wave of genetically engineered (GE) crop products has been commercialized and contributed to yield, other products – some posing significant benefits to target populations in the developing world – have become mired in controversy. Public misconception about nutritional and ecological risks, fears about multinational corporate dominance, as well as regulatory inaction have delayed the approval and use of GE crops. With new GE lines ready to pass through regulatory oversight, many of which originate from developing countries, we regard this as a pivotal moment for global acceptance of agricultural biotechnology. However, we note that some countries, international regulators, and even biotechnology companies seem willing to forego useful applications of GE crops. We conclude that educating and informing the public to combat misperception, and implementing review of regulatory guidelines based on decades of experience can help to realize the benefits of GE for food security, human well-being, and ecological sustainability.
Understanding how hormones and genes interact to coordinate plant growth in a changing environment is a major challenge in plant developmental biology. Auxin, cytokinin, and ethylene are three important hormones that regulate many aspects of plant development. This review critically evaluates the crosstalk between the three hormones in Arabidopsis root development. We integrate a variety of experimental data into a crosstalk network, which reveals multiple layers of complexity in auxin, cytokinin, and ethylene crosstalk. In particular, data integration reveals an additional, largely overlooked link between the ethylene and cytokinin pathways, which acts through a phosphorelay mechanism. This proposed link addresses outstanding questions on whether ethylene application promotes or inhibits receptor kinase activity of the ethylene receptors. Elucidating the complexity in auxin, cytokinin, and ethylene crosstalk requires a combined experimental and systems modeling approach. We evaluate important modeling efforts for establishing how crosstalk between auxin, cytokinin, and ethylene regulates patterning in root development. We discuss how a novel methodology that iteratively combines experiments with systems modeling analysis is essential for elucidating the complexity in crosstalk of auxin, cytokinin, and ethylene in root development. Finally, we discuss the future challenges from a combined experimental and modeling perspective.
Nitrogen is an essential nutrient for plant growth. World-wide, large quantities of nitrogenousfertilizer are applied to ensure maximum crop productivity. However, nitrogen fertilizerapplication is expensive and negatively affects the environment, and subsequently humanhealth. A strategy to address this problem is the development of crops that are efficient inacquiring and using nitrogen and that can achieve high seed yields with reduced nitrogen input.This review integrates the current knowledge regarding inorganic and organic nitrogenmanagement at the whole-plant level, spanning from nitrogen uptake to remobilization andutilization in source and sink organs. Plant partitioning and transient storage of inorganic andorganic nitrogen forms areevaluated, as is howthey affect nitrogenavailability, metabolism andmobilization. Essential functions of nitrogen transporters in source and sink organs and theirimportance in regulating nitrogen movement in support of metabolism, and vegetative andreproductive growth are assessed. Finally, we discuss recent advances in plant engineering,demonstrating that nitrogen transporters are effective targets to improve crop productivity andnitrogen use efficiency. While inorganic and organic nitrogen transporters were examinedseparately in these studies, they provide valuable clues about how to successfully combineapproaches for future crop engineering.
Hormone transporters are crucial for plant hormone action, which is underlined by severe developmental and physiological impacts caused by their loss-of-function mutations. Here, we summarize recent knowledge on the individual roles of plant hormone transporters in local and long-distance transport. Our inventory reveals that many hormones are transported by members of distinct transporter classes, with an apparent dominance of the ATP-binding cassette (ABC) family and of the Nitrate transport1/Peptide transporter family (NPF). The current need to explore further hormone transporter regulation, their functional interaction, transport directionalities, and substrate specificities is briefly reviewed.
Sucrose is synthesized from UDP-Glc and Fru-6-phosphate via the activity of sucrose-phosphate synthase (SPS) enzymes, which produce Suc-6-phosphate. Suc-6-phosphate is rapidly dephosphorylated by phosphatases to produce Suc and inorganic phosphate. Arabidopsis has four sps genes encoding SPS enzymes. Of these enzymes, AtSPS1F and AtSPS2F have been grouped with other dicotyledonous SPS enzymes, while AtSPS3F and AtSPS4F are included in groups with both dicotyledonous and monocotyledonous SPS enzymes. In this work, we generated Arabidopsis thaliana transformants containing the promoter region of each sps gene fused to gfp::uidA reporter genes. A detailed characterization of expression conferred by the sps promoters in organs and tissues was performed. We observed expression of AtSPS1F, AtSPS2F and AtSPS3F in the columella roots of the plants that support sucrose synthesis. Hence, these findings support the idea that sucrose synthesis occurs in the columella cells, and suggests that sucrose has a role in this tissue. In addition, the expression of AtSPS4F was identified in embryos and suggests its participation in this developmental stage. Quantitative transcriptional analysis of A. thaliana plants grown in media with different osmotic potential showed that AtSPS2F and AtSPS4F respond to osmotic stress.
Do root hairs help roots take up water from the soil? Despite the well-documented role of root hairs in phosphate uptake, their role in water extraction is controversial. We grew barley (Hordeum vulgare cv Pallas) and its root-hairless mutant brb in a root pressure chamber, whereby the transpiration rate could be varied whilst monitoring the suction in the xylem. The method provides accurate measurements of the dynamic relationship between the transpiration rate and xylem suction. The relationship between the transpiration rate and xylem suction was linear in wet soils and did not differ between genotypes. When the soil dried, the xylem suction increased rapidly and non-linearly at high transpiration rates. This response was much greater with the brb mutant, implying a reduced capacity to take up water. We conclude that root hairs facilitate the uptake of water by substantially reducing the drop in matric potential at the interface between root and soil in rapidly transpiring plants. The experiments also reinforce earlier observations that there is a marked hysteresis in the suction in the xylem when the transpiration rate is rising compared with when it is falling, and possible reasons for this behavior are discussed.
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Decade-long study involving 21 million smallholders shows how evidence-based approaches could improve food security.
Via Loïc Lepiniec
A fortnight ago Virginie Tournay, of CEVIPOV, a scientific research institute at the famous Science Po [Paris Institute of Political Studies] published the following article on her Huffingtonpost blog “Reconquering scientific culture” . A week later, the Science Technologies Action group ,published an article on the website of the business newspaper Les Echos entitled : “Don’t give up on science!” Each of these two texts was signed by forty opinion leaders: scientists, heads of laboratories, academics, politicians close to the scientific community … It’s worth noting that the authors were from both public and private sectors. While the style of the two texts is very different, they both refer to the same piece of legislation “A Resolution on National Science and Progress“, which was tabled on February 21st, 2017, at the initiative of Bernard Accoyer (LR) and Jean-Yves Le Déaut (PS). To summarise the text: it starts with the principle that: “France, heir to a long scientific, rationalist and Enlightenment tradition, has always stood for progress and the ideals of science at the service of humanity” and that, as stated in a 2016 UNESCO report, “Science, technology and innovation have game-changing abilities to address virtually all of the world’s most pressing challenges.” Also, rather worryingly, “Partisan or even sectarian discourse, based on a growing mistrust of scientific expertise are mounting a serious challenge to the spirit of the Enlightenment by attacking the very rules on which the institutionalisation of science is based.” On the basis of this observation, “The National Assembly and the Senate desire that the action and decisions of Parliament should be informed by awareness of the consequences of decisions of a scientific and technological nature, set out in ten points: science is a vector of innovation; science education should be strengthened and the government should ensure that it is taught in schools; there needs to be more interaction between science and humanities courses in the school and university curricula; the section of the philosophy curriculum devoted to science should be expanded; we should take more account of the Scientific Academies, enhance the communication process in the context of debate on the subject of risk-benefit analysis; public service broadcasting should increase the amount of scientific programming; it is important to think more about the sensible use of digital technologies; lastly, it is essential to take more notice of the studies and reports from the OPECST (Parliamentary Office for the Evaluation of Scientific and Technological Choices), which is the main organisation behind this resolution.”
Via Loïc Lepiniec
The unfolded protein response (UPR) is a eukaryotic transcriptional regulatory network that is activated upon the accumulation of malformed proteins in the endoplasmic reticulum (ER). In Arabidopsis (Arabidopsis thaliana), three bZIP transcription factors modulate the UPR: bZIP17, bZIP28, and bZIP60. Although bZIP28 and bZIP60 have been relatively well studied, the physiological and transcriptional roles of bZIP17 remain largely unknown. Here, we generated a double knockout mutant of bZIP17 and bZIP28 to elucidate the function of bZIP17. The mutant plant exhibited multiple developmental defects, including markedly reduced root elongation and constantly overinduced bZIP60 activity, indicating the essential roles of bZIP17 and bZIP28 in plant development and UPR modulation. Extended analysis of the transcriptomes of three double knockout mutants of bZIP17, bZIP28, and bZIP60 revealed that bZIP28 and bZIP60 are the major activators of the canonical induced UPR. By contrast, bZIP17 functions with bZIP28 to mediate the noninducible expression of multiple genes involved in cell growth, particularly to sustain their expression under stress conditions. Our study reveals pivotal roles of bZIP17 in the plant UPR and vegetative development, with functional redundancy to bZIP28.
Facing stressful conditions imposed by their environment and affecting their growth and their development throughout their life cycle, plants must be able to perceive, to process and to translate different stimuli into adaptive responses. Understanding the organism-coordinated responses involves a fine description of the mechanisms occurring at the cellular and molecular level. A major challenge is also to understand how the large diversity of molecules identified as signals, sensors or effectors could drive a cell to the appropriate plant response and to finally cope with various environmental cues. In this Research Topic we aim to provide an overview of various signaling mechanisms or to present new molecular signals involved in stress response and to demonstrate how basic/fundamental research on cell signaling will help to understand stress responses at the whole plant level.
Global food security is increasingly challenging in light of population increase, the impact of climate change on crop production, and limited land available for agricultural expansion. Here we outline how genome editing provides excellent and timely methods to optimize crop plants, and argue the urgency for societal acceptance and support.
Root systems can display variable architectures that contribute to survival strategies of plants. The model plant Arabidopsis thaliana possesses a tap root system, in which the primary root and lateral roots (LRs) are major architectural determinants. The phytohormone auxin fulfils multiple roles throughout LR development. In this review, we summarize recent advances in our understanding of four aspects of LR formation: (i) LR positioning, which determines the spatial distribution of lateral root primordia (LRP) and LRs along primary roots; (ii) LR initiation, encompassing the activation of nuclear migration in specified lateral root founder cells (LRFCs) up to the first asymmetric cell division; (iii) LR outgrowth, the ‘primordium-intrinsic’ patterning of de novo organ tissues and a meristem; and (iv) LR emergence, an interaction between LRP and overlaying tissues to allow passage through cell layers. We discuss how auxin signaling, embedded in a changing developmental context, plays important roles in all four phases. In addition, we discuss how rapid progress in gene network identification and analysis, modeling, and four-dimensional imaging techniques have led to an increasingly detailed understanding of the dynamic regulatory networks that control LR development.
Nitric oxide (NO), a small sized, short lived, highly diffusible natured, gaseous, diatomic and bioactive molecule, has now gained an important position in plant science research, due to its multifunctional roles in physiological as well as pathological responses in plants. A detailed understanding of the molecular mechanisms of plants against various stresses revealed that production of NO and other reactive oxygen species (ROS) are known to interplay an essential role to counter those challenges. NO can directly or indirectly help in the modulation of different protein functions and the reprogramming of defense gene expression by interacting with certain targets. NO might act as a signal in activating ROS-scavenging enzyme activities under various abiotic stresses including drought, salinity, temperature, heavy metal and radiations stress. Furthermore, application of NO donor has tremendous potential to counteract damages in different segments of plants caused by various stresses. This review aims to discuss the overall role of NO in higher plants in response to abiotic stresses.
Improving the responsiveness, acclimation, and memory of plants to abiotic stress holds substantive potential for improving agriculture. An unresolved question is the involvement of chromatin marks in the memory of agriculturally relevant stresses. Such potential has spurred numerous investigations yielding both promising and conflicting results. Consequently, it remains unclear to what extent robust stress-induced DNA methylation variation can underpin stress memory. Using a slow-onset water deprivation treatment in Arabidopsis (Arabidopsis thaliana), we investigated the malleability of the DNA methylome to drought stress within a generation and under repeated drought stress over five successive generations. While drought-associated epi-alleles in the methylome were detected within a generation, they did not correlate with drought-responsive gene expression. Six traits were analyzed for transgenerational stress memory, and the descendants of drought-stressed lineages showed one case of memory in the form of increased seed dormancy, and that persisted one generation removed from stress. With respect to transgenerational drought stress, there were negligible conserved differentially methylated regions in drought-exposed lineages compared with unstressed lineages. Instead, the majority of observed variation was tied to stochastic or preexisting differences in the epigenome occurring at repetitive regions of the Arabidopsis genome. Furthermore, the experience of repeated drought stress was not observed to influence transgenerational epi-allele accumulation. Our findings demonstrate that, while transgenerational memory is observed in one of six traits examined, they are not associated with causative changes in the DNA methylome, which appears relatively impervious to drought stress.
Boron is an essential element for plants but is toxic in excess. Therefore, plants must adapt to both limiting and excess boron conditions for normal growth. Boron transport in plants is primarily based on three transport mechanisms across the plasma membrane: passive diffusion of boric acid, facilitated diffusion of boric acid via channels, and export of borate anion via transporters. Under boron -limiting conditions, boric acid channels and borate exporters function in the uptake and translocation of boron to support growth of various plant species. In Arabidopsis thaliana, NIP5;1 and BOR1 are located in the plasma membrane and polarized toward soil and stele, respectively, in various root cells, for efficient transport of boron from the soil to the stele. Importantly, sufficient levels of boron induce downregulation of NIP5;1 and BOR1 through mRNA degradation and proteolysis through endocytosis, respectively. In addition, borate exporters, such as Arabidopsis BOR4 and barley Bot1, function in boron exclusion from tissues and cells under conditions of excess boron. Thus, plants actively regulate intracellular localization and abundance of transport proteins to maintain boron homeostasis. In this review, the physiological roles and regulatory mechanisms of intracellular localization and abundance of boron transport proteins are discussed.
Salinity exerts a severe detrimental effect on crop yields globally. Growth of plants in saline soils results in physiological stress, which disrupts the essential biochemical processes of respiration, photosynthesis, and transpiration. Understanding the molecular responses of plants exposed to salinity stress can inform future strategies to reduce agricultural losses due to salinity; however, it is imperative that signalling and functional response processes are connected to tailor these strategies. Previous research has revealed the important role that plant mitochondria play in the salinity response of plants. Review of this literature shows that 2 biochemical processes required for respiratory function are affected under salinity stress: the tricarboxylic acid cycle and the transport of metabolites across the inner mitochondrial membrane. However, the mechanisms by which components of these processes are affected or react to salinity stress are still far from understood. Here, we examine recent findings on the signal transduction pathways that lead to adaptive responses of plants to salinity and discuss how they can be involved in and be affected by modulation of the machinery of energy metabolism with attention to the role of the tricarboxylic acid cycle enzymes and mitochondrial membrane transporters in this process.
Understanding how grapevines perceive and adapt to different environments will provide us with an insight into how to better manage crop quality. Mounting evidence suggests that epigenetic mechanisms are a key interface between the environment and the genotype that ultimately affect the plant’s phenotype. Moreover, it is now widely accepted that epigenetic mechanisms are a source of useful variability during crop varietal selection that could affect crop performance. While the contribution of DNA methylation to plant performance has been extensively studied in other major crops, very little work has been done in grapevine. To study the genetic and epigenetic diversity across 22 vineyards planted with the cultivar Shiraz in six wine sub-regions of the Barossa, South Australia Methylation Sensitive Amplified Polymorphisms (MSAP) were used to obtain global patterns of DNA methylation. The observed epigenetic profiles showed a high level of differentiation that grouped vineyards by their area of provenance despite the low genetic differentiation between vineyards and sub-regions. Pairwise epigenetic distances between vineyards indicate that the main contributor (23-24%) to the detected variability is associated to the distribution of the vineyards on the N-S axis. Analysis of the methylation profiles of vineyards pruned with the same system increased the positive correlation observed between geographic distance and epigenetic distance suggesting that pruning system affects inter-vineyard epigenetic differentiation. Finally, methylation sensitive Genotyping By Sequencing identified 3,598 differentially methylated genes in grapevine leaves that were assigned to 1,144 unique GO terms of which 8.6% were associated with response to environmental stimulus. Our results suggest that DNA methylation differences between vineyards and sub-regions within The Barossa are influenced both by the geographic location and, to a lesser extent, by pruning system. Finally, we discuss how epigenetic variability can be used as a tool to understand and potentially modulate terroir in grapevine.
Plants can acquire freezing tolerance in response to cold but non-freezing temperatures. To efficiently activate this cold acclimation, low temperature has to be sensed and processed swiftly, a process that is linked with a transient elimination of microtubules. Here, we address cold-induced microtubules elimination in a grapevine cell line stably expressing a green fluorescent protein fusion of Arabidopsis TuB6, which allows to follow their response in vivo and to quantify this response by quantitative image analysis. We use time-course studies with several specific pharmacological inhibitors and activators to dissect the signalling events acting upstream of microtubules elimination. We find that microtubules disappear within 30 min after the onset of cold stress. We provide evidence for roles of calcium influx, membrane rigidification, and activation of NAD(P)H oxidase as factors in signal susception and amplification. We further conclude that a G-protein in concert with a phospholipase D convey the signal towards microtubules, whereas calmodulin seems to be not involved. Moreover, activation of jasmonate pathway in response to cold is required for an efficient microtubule response. We summarize our findings in a working model on a complex signalling hub at the membrane-cytoskeleton interphase that assembles the susception, perception and early transduction of cold signals.
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Species display a range of plastic phenotypes that presumably have evolved as a result of adaptation to heterogeneous environments. We asked whether the genetic mechanisms that underlie adaptation across populations also determine the response of an individual plant to environmental cues in Arabidopsis. Using an integrative root phenotyping approach, genes that underlie natural variation in root architecture across populations were shown to control plasticity responses within an individual. Together, our results uncover a genetic mechanism underlying the phenotypic plasticity of an individual and phenotypic diversity across natural variants.
AbstractPhenotypic plasticity is presumed to be involved in adaptive change toward species diversification. We thus examined how candidate genes underlying natural variation across populations might also mediate plasticity within an individual. Our implementation of an integrative “plasticity space” approach revealed that the root plasticity of a single Arabidopsis accession exposed to distinct environments broadly recapitulates the natural variation “space.” Genome-wide association mapping identified the known gene PHOSPHATE 1(PHO1) and other genes such as Root System Architecture 1 (RSA1) associated with differences in root allometry, a highly plastic trait capturing the distribution of lateral roots along the primary axis. The response of mutants in the Columbia-0 background suggests their involvement in signaling key modulators of root development including auxin, abscisic acid, and nitrate. Moreover, genotype-by-environment interactions for the PHO1 and RSA1 genes in Columbia-0 phenocopy the root allometry of other natural variants. This finding supports a role for plasticity responses in phenotypic evolution in natural environments.
Open Access