A quantitative gibberellin signaling biosensor reveals a role for gibberellins in internode specification at the shoot apical meristem.

Growth at the shoot apical meristem (SAM) is essential for shoot architecture construction. The phytohormones gibberellins (GA) play a pivotal role in coordinating plant growth, but their role in the SAM remains mostly unknown. Here, we developed a ratiometric GA signaling biosensor by engineering one of the DELLA proteins, to suppress its master regulatory function in GA transcriptional responses while preserving its degradation upon GA sensing. We demonstrate that this degradation-based biosensor accurately reports on cellular changes in GA levels and perception during development. We used this biosensor to map GA signaling activity in the SAM. We show that high GA signaling is found primarily in cells located between organ primordia that are the precursors of internodes. By gain- and loss-of-function approaches, we further demonstrate that GAs regulate cell division plane orientation to establish the typical cellular organization of internodes, thus contributing to internode specification in the SAM.

The translocation of a chloride channel from the Golgi to the plasma membrane helps plants adapt to salt stress.

A key mechanism employed by plants to adapt to salinity stress involves maintaining ion homeostasis via the actions of ion transporters. While the function of cation transporters in maintaining ion homeostasis in plants has been extensively studied, little is known about the roles of their anion counterparts in this process. Here, we describe a mechanism of salt adaptation in plants. We characterized the chloride channel (CLC) gene AtCLCf, whose expression is regulated by WRKY transcription factor under salt stress in Arabidopsis thaliana. Loss-of-function atclcf seedlings show increased sensitivity to salt, whereas AtCLCf overexpression confers enhanced resistance to salt stress. Salt stress induces the translocation of GFP-AtCLCf fusion protein to the plasma membrane (PM). Blocking AtCLCf translocation using the exocytosis inhibitor brefeldin-A or mutating the small GTPase gene AtRABA1b/BEX5 (RAS GENES FROM RAT BRAINA1b homolog) increases salt sensitivity in plants. Electrophysiology and liposome-based assays confirm the Cl-/H+ antiport function of AtCLCf. Therefore, we have uncovered a mechanism of plant adaptation to salt stress involving the NaCl-induced translocation of AtCLCf to the PM, thus facilitating Cl- removal at the roots, and increasing the plant's salinity tolerance.

Identification and expression analysis of the Xyloglucan transglycosylase/hydrolase (XTH) gene family under abiotic stress in oilseed (Brassica napus L.).

XTH genes are key genes that regulate the hydrolysis and recombination of XG components and plays role in the structure and composition of plant cell walls. Therefore, clarifying the changes that occur in XTHs during plant defense against abiotic stresses is informative for the study of the plant stress regulatory mechanism mediated by plant cell wall signals. XTH proteins in Arabidopsis thaliana was selected as the seed sequences in combination with its protein structural domains, 80 members of the BnXTH gene family were jointly identified from the whole genome of the Brassica napus ZS11, and analyzed for their encoded protein physicochemical properties, phylogenetic relationships, covariance relationships, and interoperating miRNAs. Based on the transcriptome data, the expression patterns of BnXTHs were analyzed in response to different abiotic stress treatments. The relative expression levels of some BnXTH genes under Al, alkali, salt, and drought treatments after 0, 6, 12 and 24 h were analyzed by using qRT-PCR to explore their roles in abiotic stress tolerance in B. napus. BnXTHs showed different expression patterns in response to different abiotic stress signals, indicating that the response mechanisms of oilseed rape against different abiotic stresses are also different. This paper provides a theoretical basis for clarifying the function and molecular genetic mechanism of the BnXTH gene family in abiotic stress tolerance in rapeseed.

A high-affinity potassium transporter (MeHKT1) from cassava (Manihot esculenta) negatively regulates the response of transgenic Arabidopsis to salt stress.

BACKGROUND: High-affinity potassium transporters (HKTs) are crucial in facilitating potassium uptake by plants. Many types of HKTs confer salt tolerance to plants through regulating K+ and Na+ homeostasis under salinity stress. However, their specific functions in cassava (Manihot esculenta) remain unclear. RESULTS: Herein, an HKT gene (MeHKT1) was cloned from cassava, and its expression is triggered by exposure to salt stress. The expression of a plasma membrane-bound protein functions as transporter to rescue a low potassium (K+) sensitivity of yeast mutant strain, but the complementation of MeHKT1 is inhibited by NaCl treatment. Under low K+ stress, transgenic Arabidopsis with MeHKT1 exhibits improved growth due to increasing shoot K+ content. In contrast, transgenic Arabidopsis accumulates more Na+ under salt stress than wild-type (WT) plants. Nevertheless, the differences in K+ content between transgenic and WT plants are not significant. Additionally, Arabidopsis expressing MeHKT1 displayed a stronger salt-sensitive phenotype. CONCLUSION: These results suggest that under low K+ condition, MeHKT1 functions as a potassium transporter. In contrast, MeHKT1 mainly transports Na+ into cells under salt stress condition and negatively regulates the response of transgenic Arabidopsis to salt stress. Our results provide a reference for further research on the function of MeHKT1, and provide a basis for further application of MeHKT1 in cassava by molecular biological means.

Characterisation of the Arabidopsis thaliana telomerase TERT-TR complex.

Most eukaryotic organisms employ a telomerase complex for the maintenance of chromosome ends. The core of this complex is composed of telomerase reverse transcriptase (TERT) and telomerase RNA (TR) subunits. The TERT reverse transcriptase (RT) domain synthesises telomeric DNA using the TR template sequence. The other TERT domains contribute to this process in different ways. In particular, the TERT RNA-binding domain (TRBD) interacts with specific TR motif(s). Using a yeast 3-hybrid system, we show the critical role of Arabidopsis thaliana (At) TRBD and embryophyta-conserved KRxR motif in the unstructured linker preceding the TRBD domain for binding to the recently identified AtTR subunit. We also show the essential role of the predicted P4 stem and pseudoknot AtTR structures and provide evidence for the binding of AtTRBD to pseudoknot and KRxR motif stabilising interaction with the P4 stem structure. Our results thus provide the first insight into the core part of the plant telomerase complex.

Molecular cloning and characterization of a salt overly sensitive3 (SOS3) gene from the halophyte Pongamia.

A high concentration of sodium (Na+) is the primary stressor for plants in high salinity environments. The Salt Overly Sensitive (SOS) pathway is one of the best-studied signal transduction pathways, which confers plants the ability to export too much Na+ out of the cells or translocate the cytoplasmic Na+ into the vacuole. In this study, the Salt Overly Sensitive3 (MpSOS3) gene from Pongamia (Millettia pinnata Syn. Pongamia pinnata), a semi-mangrove, was isolated and characterized. The MpSOS3 protein has canonical EF-hand motifs conserved in other calcium-binding proteins and an N-myristoylation signature sequence. The MpSOS3 gene was significantly induced by salt stress, especially in Pongamia roots. Expression of the wild-type MpSOS3 but not the mutated nonmyristoylated MpSOS3-G2A could rescue the salt-hypersensitive phenotype of the Arabidopsis sos3-1 mutant, which suggested the N-myristoylation signature sequence of MpSOS3 was required for MpSOS3 function in plant salt tolerance. Heterologous expression of MpSOS3 in Arabidopsis accumulated less H2O2, superoxide anion radical (O2-), and malondialdehyde (MDA) than wild-type plants, which enhanced the salt tolerance of transgenic Arabidopsis plants. Under salt stress, MpSOS3 transgenic plants accumulated a lower content of Na+ and a higher content of K+ than wild-type plants, which maintained a better K+/Na+ ratio in transgenic plants. Moreover, no development and growth discrepancies were observed in the MpSOS3 heterologous overexpression plants compared to wild-type plants. Our results demonstrated that the MpSOS3 pathway confers a conservative salt-tolerant role and provided a foundation for further study of the SOS pathway in Pongamia.

Cloning and functional validation of DsWRKY6 gene from Desmodium styracifolium.

The purpose of this study was to analyze the role of transcription factor in Desmodium styracifolium, proving that the DsWRKY6 transcription factor was related to the plant phenotypes of Desmodium styracifolium - cv. 'GuangYaoDa1' and it could be used in molecular-assisted breeding. 'GuangYaoDa1' was used as the material and its DNA was the template to clone DsWRKY6, the transgenic Arabidopsis thaliana line was constructed by agrobacterium tumefaciens­mediated transformation. Transgenic Arabidopsis thaliana was cultivated to study phenotype and physiological and biochemical indexes. Phenotypic observation showed that DsWRKY6 transgenic Arabidopsis thaliana had a faster growth rate while compared with the control group, they had longer lengths of main stem, lateral branches of cauline leaves, and root, but a lower number of cauline leaves and lateral branches of cauline leaves. And it also showed that their flowering and fruiting periods were advanced. The results of physiological and biochemical indexes showed that the relative expressions of DsWRKY6 increased and the abscisic acid content significantly increased in DsWRKY6 transgenic Arabidopsis thaliana compared with the control group. According to the above results, DsWRKY6 could regulate the advancing of flowering and fruiting periods caused by the improvement of abscisic acid content, and expression of the DsWRKY6 transcription factor might be the cause of the upright growth of 'GuangYaoDa1'.

Control of Sclerotinia sclerotiorum via an RNA interference (RNAi)-mediated targeting of SsPac1 and SsSmk1.

MAIN CONCLUSION: The study evaluates the potential of Spray-Induced Gene Silencing and Host-Induced Gene Silencing for sustainable crop protection against the broad-spectrum necrotrophic fungus Sclerotinia sclerotiorum. Sclerotinia sclerotiorum (Lib.) de Bary, an aggressive ascomycete fungus causes white rot or cottony rot on a broad range of crops including Brassica juncea. The lack of sustainable control measures has necessitated biotechnological interventions such as RNA interference (RNAi) for effective pathogen control. Here we adopted two RNAi-based strategies-Spray-Induced Gene Silencing (SIGS) and Host-Induced Gene Silencing (HIGS) to control S. sclerotiorum. SIGS was successful in controlling white rot on Nicotiana benthamiana and B. juncea by targeting SsPac1, a pH-responsive transcription factor and SsSmk1, a MAP kinase involved in fungal development and pathogenesis. Topical application of dsRNA targeting SsPac1 and SsSmk1 delayed infection initiation and progression on B. juncea. Further, altered hyphal morphology and reduced radial growth were also observed following dsRNA application. We also explored the impact of stable dsRNA expression in A. thaliana against S. sclerotiorum. In this report, we highlight the utility of RNAi as a biofungicide and a tool for preliminary functional genomics.

A network-based modeling framework reveals the core signal transduction network underlying high carbon dioxide-induced stomatal closure in guard cells.

Stomata are pores on plant aerial surfaces, each bordered by a pair of guard cells. They control gas exchange vital for plant survival. Understanding how guard cells respond to environmental signals such as atmospheric carbon dioxide (CO2) levels is not only insightful to fundamental biology but also relevant to real-world issues of crop productivity under global climate change. In the past decade, multiple important signaling elements for stomatal closure induced by elevated CO2 have been identified. Yet, there is no comprehensive understanding of high CO2-induced stomatal closure. In this work, we assemble a cellular signaling network underlying high CO2-induced stomatal closure by integrating evidence from a comprehensive literature analysis. We further construct a Boolean dynamic model of the network, which allows in silico simulation of the stomatal closure response to high CO2 in wild-type Arabidopsis thaliana plants and in cases of pharmacological or genetic manipulation of network nodes. Our model has a 91% accuracy in capturing known experimental observations. We perform network-based logical analysis and reveal a feedback core of the network, which dictates cellular decisions in closure response to high CO2. Based on these analyses, we predict and experimentally confirm that applying nitric oxide (NO) induces stomatal closure in ambient CO2 and causes hypersensitivity to elevated CO2. Moreover, we predict a negative regulatory relationship between NO and the protein phosphatase ABI2 and find experimentally that NO inhibits ABI2 phosphatase activity. The experimental validation of these model predictions demonstrates the effectiveness of network-based modeling and highlights the decision-making role of the feedback core of the network in signal transduction. We further explore the model's potential in predicting targets of signaling elements not yet connected to the CO2 network. Our combination of network science, in silico model simulation, and experimental assays demonstrates an effective interdisciplinary approach to understanding system-level biology.

Comprehensive identification of maize ZmE2F transcription factors and the positive role of ZmE2F6 in response to drought stress.

BACKGROUND: The early 2 factor (E2F) family is characterized as a kind of transcription factor that plays an important role in cell division, DNA damage repair, and cell size regulation. However, its stress response has not been well revealed. RESULTS: In this study, ZmE2F members were comprehensively identified in the maize genome, and 21 ZmE2F genes were identified, including eight E2F subclade members, seven DEL subfamily genes, and six DP genes. All ZmE2F proteins possessed the DNA-binding domain (DBD) characterized by conserved motif 1 with the RRIYD sequence. The ZmE2F genes were unevenly distributed on eight maize chromosomes, showed diversity in gene structure, expanded by gene duplication, and contained abundant stress-responsive elements in their promoter regions. Subsequently, the ZmE2F6 gene was cloned and functionally verified in drought response. The results showed that the ZmE2F6 protein interacted with ZmPP2C26, localized in the nucleus, and responded to drought treatment. The overexpression of ZmE2F6 enhanced drought tolerance in transgenic Arabidopsis with longer root length, higher survival rate, and biomass by upregulating stress-related gene transcription. CONCLUSIONS: This study provides novel insights into a greater understanding and functional study of the E2F family in the stress response.

Expressing banana transcription factor MaERFVII3 in Arabidopsis confers enhanced waterlogging tolerance and root growth.

Background: Waterlogging poses a significant threat to plant growth and yield worldwide. Identifying the genes responsible for mitigating waterlogging stress is crucial. Ethylene-responsive factors (ERFs) are transcriptional regulators that respond to various biotic and abiotic stresses in plants. However, their roles and involvement in responding to waterlogging stress remain largely unexplored. Hence, this study aimed to elucidate the role of ERFs in enhancing banana plant resilience to waterlogging. Methods: We hypothesized that introducing a group VII ERF transcription factor in Arabidopsis could enhance waterlogging stress tolerance. To test this hypothesis, we isolated MaERFVII3 from banana roots, where it exhibited a significant induction in response to waterlogging stress. The isolated MaERFVII3 was introduced into Arabidopsis plants for functional gene studies. Results: Compared with wild-type plants, the MaERFVII3-expressing Arabidopsis showed increased survival and biomass under waterlogging stress. Furthermore, the abundance of transcripts related to waterlogging and hypoxia response showed an elevation in transgenic plants but a decrease in wild-type and empty vector plants when exposed to waterlogging stress. Our results demonstrate the significant contribution of MaERFVII3 to waterlogging tolerance in Arabidopsis, providing baseline data for further exploration and potentially contributing to crop improvement programs.

Transcriptome analysis and functional validation reveal the novel role of LhCYCL in axillary bud development in hybrid Liriodendron.

Shoot branching significantly influences yield and timber quality in woody plants, with hybrid Liriodendron being particularly valuable due to its rapid growth. However, understanding of the mechanisms governing shoot branching in hybrid Liriodendron remains limited. In this study, we systematically examined axillary bud development using morphological and anatomical approaches and selected four distinct developmental stages for an extensive transcriptome analysis. A total of 9,449 differentially expressed genes have been identified, many of which are involved in plant hormone signal transduction pathways. Additionally, we identified several transcription factors downregulated during early axillary bud development, including a noteworthy gene annotated as CYC-like from the TCP TF family, which emerged as a strong candidate for modulating axillary bud development. Quantitative real-time polymerase chain reaction results confirmed the highest expression levels of LhCYCL in hybrid Liriodendron axillary buds, while histochemical ß-glucuronidase staining suggested its potential role in Arabidopsis thaliana leaf axil development. Ectopic expression of LhCYCL in A. thaliana led to an increase of branches and a decrease of plant height, accompanied by altered expression of genes involved in the plant hormone signaling pathways. This indicates the involvement of LhCYCL in regulating shoot branching through plant hormone signaling pathways. In summary, our results emphasize the pivotal role played by LhCYCL in shoot branching, offering insights into the function of the CYC-like gene and establishing a robust foundation for further investigations into the molecular mechanisms governing axillary bud development in hybrid Liriodendron.

Crucial role of SWL1 in chloroplast biogenesis and development in Arabidopsis thaliana.

KEY MESSAGE: The disruption of the SWL1 gene leads to a significant down regulation of chloroplast and secondary metabolites gene expression in Arabidopsis thaliana. And finally results in a dysfunction of chloroplast and plant growth. Although the development of the chloroplast has been a consistent focus of research, the corresponding regulatory mechanisms remain unidentified. In this study, the CRISPR/Cas9 system was used to mutate the SWL1 gene, resulting in albino cotyledons and variegated true leaf phenotype. Confocal microscopy and western blot of chloroplast protein fractions revealed that SWL1 localized in the chloroplast stroma. Electron microscopy indicated chloroplasts in the cotyledons of swl1 lack well-defined grana and internal membrane structures, and similar structures have been detected in the albino region of variegated true leaves. Transcriptome analysis revealed that down regulation of chloroplast and nuclear gene expression related to chloroplast, including light harvesting complexes, porphyrin, chlorophyll metabolism and carbon metabolism in the swl1 compared to wild-type plant. In addition, proteomic analysis combined with western blot analysis, showed that a significant decrease in chloroplast proteins of swl1. Furthermore, the expression of genes associated with secondary metabolites and growth hormones was also reduced, which may be attributed to SWL1 associated with absorption and fixation of inorganic carbon during chloroplast development. Together, the above findings provide valuable information to elucidate the exact function of SWL1 in chloroplast biogenesis and development.

ACRE, a class of AP2/ERF transcription factors, activates the expression of sweet potato ß-amylase and sporamin genes through the sugar-responsible element CMSRE-1.

Sugars, synthesized by photosynthesis in source organs, are loaded and utilized as an energy source and carbon skeleton in sink organs, and also known to be important signal molecules regulating gene expression in higher plants. The expression of genes coding for sporamin and ß-amylase, the two most abundant proteins in storage roots of sweet potato, is coordinately induced by sugars. We previously reported on the identification of the carbohydrate metabolic signal-responsible element-1 (CMSRE-1) essential for the sugar-responsible expression of two genes. However, transcription factors that bind to this sequence have not been identified. In this study, we performed yeast one-hybrid screening using the sugar-responsible minimal promoter region of the ß-amylase gene as bait and a library composed only transcription factor cDNAs of Arabidopsis. Two clones, named Activator protein binding to CMSRE-1 (ACRE), encoding AP2/ERF transcription factors were isolated. ACRE showed transactivation activity of the sugar-responsible minimal promoter in a CMSRE-1-dependent manner in Arabidopsis protoplasts. Electric mobility shift assay (EMSA) using recombinant proteins and transient co-expression assay in Arabidopsis protoplasts revealed that ACRE could actually act to the CMSRE-1. Among the DEHYDRATION -RESPONSIVE ELEMENT BINDING FACTOR (DREB) subfamily, almost all homologs including ACRE, could act on the DRE, while only three ACREs could act to the CMSRE-1. Moreover, ACRE-homologs of Japanese morning glory also have the same property of DNA-binding preference and transactivation activity through the CMSRE-1. These findings suggested that ACRE plays an important role in the mechanism regulating the sugar-responsible gene expression through the CMSRE-1 conserved across plant species.

Arabidopsis α-Aurora kinase plays a role in cytokinesis through regulating MAP65-3 association with microtubules at phragmoplast midzone.

The α-Aurora kinase is a crucial regulator of spindle microtubule organization during mitosis in plants. Here, we report a post-mitotic role for α-Aurora in reorganizing the phragmoplast microtubule array. In Arabidopsis thaliana, α-Aurora relocated from spindle poles to the phragmoplast midzone, where it interacted with the microtubule cross-linker MAP65-3. In a hypomorphic α-Aurora mutant, MAP65-3 was detected on spindle microtubules, followed by a diffuse association pattern across the phragmoplast midzone. Simultaneously, phragmoplast microtubules remained belatedly in a solid disk array before transitioning to a ring shape. Microtubules at the leading edge of the matured phragmoplast were often disengaged, accompanied by conspicuous retentions of MAP65-3 at the phragmoplast interior edge. Specifically, α-Aurora phosphorylated two residues towards the C-terminus of MAP65-3. Mutation of these residues to alanines resulted in an increased association of MAP65-3 with microtubules within the phragmoplast. Consequently, the expansion of the phragmoplast was notably slower compared to wild-type cells or cells expressing a phospho-mimetic variant of MAP65-3. Moreover, mimicking phosphorylation reinstated disrupted MAP65-3 behaviors in plants with compromised α-Aurora function. Overall, our findings reveal a mechanism in which α-Aurora facilitates cytokinesis progression through phosphorylation-dependent restriction of MAP65-3 associating with microtubules at the phragmoplast midzone.

H2S is involved in drought-mediated stomatal closure through PLDα1 in Arabidopsis.

MAIN CONCLUSION: PLDα1 promoted H2S production by positively regulating the expression of LCD. Stomatal closure promoted by PLDα1 required the accumulation of H2S under drought stress. Phospholipase Dα1 (PLDα1) acting as one of the signal enzymes can respond to drought stress. It is well known that hydrogen sulfide (H2S) plays an important role in plant responding to biotic or abiotic stress. In this study, the functions and relationship between PLDα1 and H2S in drought stress resistance in Arabidopsis were explored. Our results indicated that drought stress promotes PLDα1 and H2S production by inducing the expression of PLDα1 and LCD genes. PLDα1 and LCD enhanced plant tolerance to drought by regulating membrane lipid peroxidation, proline accumulation, H2O2 content and stomatal closure. Under drought stress, the H2O2 content of PLDα1-deficient mutant (pldα1), L-cysteine desulfhydrase (LCD)-deficient mutant (lcd) was higher than that of ecotype (WT), the stomatal aperture of pldα1 and lcd was larger than that of WT. The transcriptional and translational levels of LCD were lower in pldα1 than that in WT. Exogenous application of the H2S donor NaHS or GYY reduced the stomatal aperture of WT, pldα1, PLDα1-CO, and PLDα1-OE lines, while exogenous application of the H2S scavenger hypotaurine (HT) increased the stomatal aperture. qRT-PCR analysis of stomatal movement-related genes showed that the expression of CAX1, ABCG5, SCAB1, and SLAC1 genes in pldα1 and lcd were down-regulated, while ACA1 and OST1 gene expression was significantly up-regulated. Thus, PLDα1 and LCD are required for stomatal closure to improve drought stress tolerance.

Investigating the mechanism of chloroplast singlet oxygen signaling in the Arabidopsis thaliana accelerated cell death 2 mutant.

As sessile organisms, plants have evolved complex signaling mechanisms to sense stress and acclimate. This includes the use of reactive oxygen species (ROS) generated during dysfunctional photosynthesis to initiate signaling. One such ROS, singlet oxygen (1O2), can trigger retrograde signaling, chloroplast degradation, and programmed cell death. However, the signaling mechanisms are largely unknown. Several proteins (e.g. PUB4, OXI1, EX1) are proposed to play signaling roles across three Arabidopsis thaliana mutants that conditionally accumulate chloroplast 1O2 (fluorescent in blue light (flu), chlorina 1 (ch1), and plastid ferrochelatase 2 (fc2)). We previously demonstrated that these mutants reveal at least two chloroplast 1O2 signaling pathways (represented by flu and fc2/ch1). Here, we test if the 1O2-accumulating lesion mimic mutant, accelerated cell death 2 (acd2), also utilizes these pathways. The pub4-6 allele delayed lesion formation in acd2 and restored photosynthetic efficiency and biomass. Conversely, an oxi1 mutation had no measurable effect on these phenotypes. acd2 mutants were not sensitive to excess light (EL) stress, yet pub4-6 and oxi1 both conferred EL tolerance within the acd2 background, suggesting that EL-induced 1O2 signaling pathways are independent from spontaneous lesion formation. Thus, 1O2 signaling in acd2 may represent a third (partially overlapping) pathway to control cellular degradation.

Investigation of Arabidopsis root skototropism with different distance settings.

Plants can activate protective and defense mechanisms under biotic and abiotic stresses. Their roots naturally grow in the soil, but when they encounter sunlight in the top-soil layers, they may move away from the light source to seek darkness. Here we investigate the skototropic behavior of roots, which promotes their fitness and survival. Glutamate-like receptors (GLRs) of plants play roles in sensing and responding to signals, but their role in root skototropism is not yet understood. Light-induced tropisms are known to be affected by auxin distribution, mainly determined by auxin efflux proteins (PIN proteins) at the root tip. However, the role of PIN proteins in root skototropism has not been investigated yet. To better understand root skototropism and its connection to the distance between roots and light, we established five distance settings between seedlings and darkness to investigate the variations in root bending tendencies. We compared differences in root skototropic behavior across different expression lines of Arabidopsis thaliana seedlings (atglr3.7 ko, AtGLR3.7 OE, and pin2 knockout) to comprehend their functions. Our research shows that as the distance between roots and darkness increases, the root's positive skototropism noticeably weakens. Our findings highlight the involvement of GLR3.7 and PIN2 in root skototropism.

Variation and plasticity in life-history traits and fitness of wild Arabidopsis thaliana populations are not related to their genotypic and ecological diversity.

BACKGROUND: Despite its implications for population dynamics and evolution, the relationship between genetic and phenotypic variation in wild populations remains unclear. Here, we estimated variation and plasticity in life-history traits and fitness of the annual plant Arabidopsis thaliana in two common garden experiments that differed in environmental conditions. We used up to 306 maternal inbred lines from six Iberian populations characterized by low and high genotypic (based on whole-genome sequences) and ecological (vegetation type) diversity. RESULTS: Low and high genotypic and ecological diversity was found in edge and core Iberian environments, respectively. Given that selection is expected to be stronger in edge environments and that ecological diversity may enhance both phenotypic variation and plasticity, we expected genotypic diversity to be positively associated with phenotypic variation and plasticity. However, maternal lines, irrespective of the genotypic and ecological diversity of their population of origin, exhibited a substantial amount of phenotypic variation and plasticity for all traits. Furthermore, all populations harbored maternal lines with canalization (robustness) or sensitivity in response to harsher environmental conditions in one of the two experiments. CONCLUSIONS: Overall, we conclude that the environmental attributes of each population probably determine their genotypic diversity, but all populations maintain substantial phenotypic variation and plasticity for all traits, which represents an asset to endure in changing environments.