Plant Arabidopsis Thaliana Research Articles

Data-driven crop growth simulation on time-varying generated images using multi-conditional generative adversarial networks

BackgroundImage-based crop growth modeling can substantially contribute to precision agriculture by revealing spatial crop development over time, which allows an early and location-specific estimation of relevant future plant traits, such as leaf area or biomass. A prerequisite for realistic and sharp crop image generation is the integration of multiple growth-influencing conditions in a model, such as an image of an initial growth stage, the associated growth time, and further information about the field treatment. While image-based models provide more flexibility for crop growth modeling than process-based models, there is still a significant research gap in the comprehensive integration of various growth-influencing conditions. Further exploration and investigation are needed to address this gap.MethodsWe present a two-stage framework consisting first of an image generation model and second of a growth estimation model, independently trained. The image generation model is a conditional Wasserstein generative adversarial network (CWGAN). In the generator of this model, conditional batch normalization (CBN) is used to integrate conditions of different types along with the input image. This allows the model to generate time-varying artificial images dependent on multiple influencing factors. These images are used by the second part of the framework for plant phenotyping by deriving plant-specific traits and comparing them with those of non-artificial (real) reference images. In addition, image quality is evaluated using multi-scale structural similarity (MS-SSIM), learned perceptual image patch similarity (LPIPS), and Fréchet inception distance (FID). During inference, the framework allows image generation for any combination of conditions used in training; we call this generation data-driven crop growth simulation.ResultsExperiments are performed on three datasets of different complexity. These datasets include the laboratory plant Arabidopsis thaliana (Arabidopsis) and crops grown under real field conditions, namely cauliflower (GrowliFlower) and crop mixtures consisting of faba bean and spring wheat (MixedCrop). In all cases, the framework allows realistic, sharp image generations with a slight loss of quality from short-term to long-term predictions. For MixedCrop grown under varying treatments (different cultivars, sowing densities), the results show that adding these treatment information increases the generation quality and phenotyping accuracy measured by the estimated biomass. Simulations of varying growth-influencing conditions performed with the trained framework provide valuable insights into how such factors relate to crop appearances, which is particularly useful in complex, less explored crop mixture systems. Further results show that adding process-based simulated biomass as a condition increases the accuracy of the derived phenotypic traits from the predicted images. This demonstrates the potential of our framework to serve as an interface between a data-driven and a process-based crop growth model.ConclusionThe realistic generation and simulation of future plant appearances is adequately feasible by multi-conditional CWGAN. The presented framework complements process-based models and overcomes their limitations, such as the reliance on assumptions and the low exact field-localization specificity, by realistic visualizations of the spatial crop development that directly lead to a high explainability of the model predictions.

Functional analysis of the key BrSWEET genes for sugar transport involved in the Brassica rapa-Plasmodiophora brassicae interaction

Plasmodiophora brassicae, the causative agent of clubroot disease, establishes a long-lasting parasitic relationship with its host by inducing the expression of sugar transporters. Previous studies have indicated that most BrSWEET genes in Chinese cabbage are up-regulated upon infection with P. brassicae. However, the key BrSWEET genes responsive to P. brassicae have not been definitively identified. In this study, we selected five BrSWEET genes and conducted a functional analysis of them. These five BrSWEET genes showed a notable up-regulation in roots after P. brassicae inoculation. Furthermore, these BrSWEET proteins were localized to the plasma membrane. Yeast functional complementation assays confirmed transport activity for glucose, fructose, or sucrose in four BrSWEETs, with the exception of BrSWEET2a. Mutants and silenced plants of BrSWEET1a, -11a, and -12a showed lower clubroot disease severity compared to wild-type plants, while gain-of-function Arabidopsis thaliana plants overexpressing these three BrSWEET genes exhibited significantly higher disease incidence and severity. Our findings suggested that BrSWEET1a, BrSWEET11a, and BrSWEET12a play pivotal roles in P. brassicae-induced gall formation, shedding light on the role of sugar transporters in host-pathogen interactions.

The effector-triggered immunity landscape of tomato against Pseudomonas syringae

Tomato (Solanum lycopersicum) is one of the world’s most important food crops, and as such, its production needs to be protected from infectious diseases that can significantly reduce yield and quality. Here, we survey the effector-triggered immunity (ETI) landscape of tomato against the bacterial pathogen Pseudomonas syringae. We perform comprehensive ETI screens in five cultivated tomato varieties and two wild relatives, as well as an immunodiversity screen on a collection of 149 tomato varieties that includes both wild and cultivated varieties. The screens reveal a tomato ETI landscape that is more limited than what was previously found in the model plant Arabidopsis thaliana. We also demonstrate that ETI eliciting effectors can protect tomato against P. syringae infection when the effector is delivered by a non-virulent strain either prior to or simultaneously with a virulent strain. Overall, our findings provide a snapshot of the ETI landscape of tomatoes and demonstrate that ETI can be used as a biocontrol treatment to protect crop plants.

Wheat MIXTA-like Transcriptional Activators Positively Regulate Cuticular Wax Accumulation.

MIXTA-like transcription factors AtMYB16 and AtMYB106 play important roles in the regulation of cuticular wax accumulation in dicot model plant Arabidopsis thaliana, but there are very few studies on the MIXTA-like transcription factors in monocot plants. Herein, wheat MIXTA-like transcription factors TaMIXTA1 and TaMIXTA2 were characterized as positive regulators of cuticular wax accumulation. The virus-induced gene silencing experiments showed that knock-down of wheat TaMIXTA1 and TaMIXTA2 expressions resulted in the decreased accumulation of leaf cuticular wax, increased leaf water loss rate, and potentiated chlorophyll leaching. Furthermore, three wheat orthologous genes of ECERIFERUM 5 (TaCER5-1A, 1B, and 1D) and their function in cuticular wax deposition were reported. The silencing of TaCER5 by BSMV-VIGS led to reduced loads of leaf cuticular wax and enhanced rates of leaf water loss and chlorophyll leaching, indicating the essential role of the TaCER5 gene in the deposition of wheat cuticular wax. In addition, we demonstrated that TaMIXTA1 and TaMIXTA2 function as transcriptional activators and could directly stimulate the transcription of wax biosynthesis gene TaKCS1 and wax deposition gene TaCER5. The above results strongly support that wheat MIXTA-Like transcriptional activators TaMIXTA1 and TaMIXTA2 positively regulate cuticular wax accumulation via activating TaKCS1 and TaCER5 gene transcription.

Revealing critical mechanisms in determining sorghum resistance to drought and salt using mRNA, small RNA and degradome sequencing

BackgroundPlant growth and development are severely threatened by drought and salt stresses. Compared with structural genes, transcription factors (TFs) play more pivotal roles in plant growth and stress adaptation. However, the underlying mechanisms of sorghum adapting to drought and salt are insufficient, and systematic analysis of TFs in response to the above stresses is lacking.ResultsIn this study, TFs were identified in sorghum and model plants (Arabidopsis thaliana and rice), and gene number and conserved domain were compared between sorghum and model plants. According to syntenic analysis, the expansion of sorghum and rice TFs may be due to whole-genome duplications. Between sorghum and model plants TFs, specific conserved domains were identified and they may be related to functional diversification of TFs. Forty-five key genes in sorghum, including four TFs, were likely responsible for drought adaption based on differently expression analysis. MiR5072 and its target gene (Sobic.001G449600) may refer to the determination of sorghum drought resistance according to small RNA and degradome analysis. Six genes were associated with drought adaptation of sorghum based on weighted gene co-expression network analysis (WGCNA). Similarly, the core genes in response to salt were also characterized using the above methods. Finally, 15 candidate genes, particularly two TFs (Sobic.004G300300, HD-ZIP; Sobic.003G244100, bZIP), involved in combined drought and salt resistance of sorghum were identified.ConclusionsIn summary, the findings in this study help clarify the molecular mechanisms of sorghum responding to drought and salt. We identified candidate genes and provide important genetic resource for potential development of drought-tolerant and salt-tolerant sorghum plants.

Malate dehydrogenase in plants: evolution, structure, and a myriad of functions.

Malate dehydrogenase (MDH) catalyzes the interconversion of oxaloacetate and malate coupled to the oxidation/reduction of coenzymes NAD(P)H/NAD(P)+. While most animals have two isoforms of MDH located in the cytosol and mitochondria, all major groups of land plants have at least six MDHs localized to the cytosol, mitochondria, plastids, and peroxisomes. This family of enzymes participates in important reactions in plant cells including photosynthesis, photorespiration, lipid metabolism, and NH4+ metabolism. MDH also helps to regulate the energy balance in the cell and may help the plant cope with various environmental stresses. Despite their functional diversity, all of the plant MDH enzymes share a similar structural fold and act as dimers. In this review, we will introduce readers to our current understanding of the plant MDHs, including their evolution, structure, and function. The focus will be on the MDH enzymes of the model plant Arabidopsis thaliana.

Evaluation of Chemical-Inducible Gene Expression Systems for Beet Cyst Nematode Infection Assays in Arabidopsis thaliana.

Cyst nematodes co-opt plant developmental programs for the establishment of a permanent feeding site called a syncytium in plant roots. In recent years, the role of plant developmental genes in syncytium formation has gained much attention. One main obstacle in studying the function of development-related genes in syncytium formation is that mutation or ectopic expression of such genes can cause pleiotropic phenotypes, making it difficult to interpret nematode-related phenotypes or, in some cases, impossible to carry out infection assays due to aberrant root development. Here, we tested three commonly used inducible gene expression systems for their application in beet cyst nematode infection assays of the model plant Arabidopsis thaliana. We found that even a low amount of ethanol diminished nematode development, deeming the ethanol-based system unsuitable for use in cyst nematode infection assays, whereas treatment with estradiol or dexamethasone did not negatively affect cyst nematode viability. Dose and time course responses showed that in both systems, a relatively low dose of inducer (1 μM) is sufficient to induce high transgene expression within 24 h of treatment. Transgene expression peaked at 3 to 5 days post-induction and began to decline thereafter, providing a perfect window for inducible transgenes to interfere with syncytium establishment while minimizing any adverse effects on root development. These results indicate that both estradiol- and dexamethasone-based inducible gene expression systems are suitable for cyst nematode infection assays. The employment of such systems provides a powerful tool to investigate the function of essential plant developmental genes in syncytium formation. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Uncovering genes involved in pollinator-driven mating system shifts and selfing syndrome evolution in Brassica rapa.

Shifts in pollinator occurrence and their pollen transport effectiveness drive the evolution of mating systems in flowering plants. Understanding the genomic basis of these changes is essential for predicting the persistence of a species under environmental changes. We investigated the genomic changes in Brassica rapa over nine generations of pollination by hoverflies associated with rapid morphological evolution toward the selfing syndrome. We combined a genotyping-by-sequencing (GBS) approach with a genome-wide association study (GWAS) to identify candidate genes, and assessed their functional role in the observed morphological changes by studying mutations of orthologous genes in the model plant Arabidopsis thaliana. We found 31 candidate genes involved in a wide range of functions from DNA/RNA binding to transport. Our functional assessment of orthologous genes in A. thaliana revealed that two of the identified genes in B. rapa are involved in regulating the size of floral organs. We found a protein kinase superfamily protein involved in petal width, an important trait in plant attractiveness to pollinators. Moreover, we found a histone lysine methyltransferase (HKMT) associated with stamen length. Altogether, our study shows that hoverfly pollination leads to rapid evolution toward the selfing syndrome mediated by polygenic changes.

A mature liquid fertilizer derived from cattle urine promotes Arabidopsis thaliana growth via hormone-like responses.

To understand the fertilization effects of liquid fertilizer (LF) produced by aerobic microbial processing of cattle urine, we investigated the influence of LF on growth and shoot genetic responses of the model plant Arabidopsis thaliana. LF significantly enhanced both shoot and root growth under aseptic conditions. Although filtrate from ultrafiltration (molecular weight cutoff: 10000) also promoted shoot growth and root elongation, the concentrate only promoted root growth. Multiple growth-promoting factors were therefore associated with the growth promotion. Transcriptome analysis of shoots following LF addition identified 353 upregulated and 512 downregulated genes. According to gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses, signal transduction of a phytohormone cytokinin was influenced by LF addition. Cytochrome P450 induction triggered the related signal transitions, and would introduce the growth promotion for shoot. Primary auxin responses and abscisic acid signaling responses were also observed in the presence of LF. Ethylene signaling seemed to be insensitive.

The role of the plant microbiome for forestry, agriculture and urban greenspace in times of environmental change.

This Lilliput article provides a literature overview on ecological effects of the plant microbiome with a focus on practical application in forestry, agriculture and urban greenspace under the spectre of climate change. After an overview of the mostly bacterial microbiome of the model plant Arabidopsis thaliana, worldwide data from forests reveal ecological differentiation with respect to major guilds of predominantly fungal plant root symbionts. The plant-microbiome association forms a new holobiont, an integrated unit for ecological adaptation and evolutionary selection. Researchers explored the impact of the microbiome on the capacity of plants to adapt to changing climate conditions. They investigated the impact of the microbiome in reforestation programs, after wildfire, drought, salination and pollution events in forestry, grasslands and agriculture. With increasing temperatures plant populations migrate to higher latitudes and higher altitudes. Ecological studies compared the dispersal capacity of plant seeds with that of soil microbes and the response of soil and root microbes to experimental heating of soils. These studies described a succession of microbiome associations and the kinetics of a release of stored soil carbon into the atmosphere enhancing global warming. Scientists explored the impact of synthetic microbial communities (SynComs) on rice productivity or tea quality; of whole soil addition in grassland restoration; or single fungal inoculation in maize fields. Meta-analyses of fungal inoculation showed overall a positive effect, but also a wide variation in effect sizes. Climate change will be particularly prominent in urban areas ("urban heat islands") where more than half of the world population is living. Urban landscape architecture will thus have an important impact on human health and studies started to explore the contribution of the microbiome from urban greenspace to ecosystem services.

Positive roles of the Ca2+ sensors GbCML45 and GbCML50 in improving cotton Verticillium wilt resistance.

As a universal second messenger, cytosolic calcium (Ca2+) functions in multifaceted intracellular processes, including growth, development and responses to biotic/abiotic stresses in plant. The plant-specific Ca2+ sensors, calmodulin and calmodulin-like (CML) proteins, function as members of the second-messenger system to transfer Ca2+ signal into downstream responses. However, the functions of CMLs in the responses of cotton (Gossypium spp.) after Verticillium dahliae infection, which causes the serious vascular disease Verticillium wilt, remain elusive. Here, we discovered that the expression level of GbCML45 was promoted after V. dahliae infection in roots of cotton, suggesting its potential role in Verticillium wilt resistance. We found that knockdown of GbCML45 in cotton plants decreased resistance while overexpression of GbCML45 in Arabidopsis thaliana plants enhanced resistance to V. dahliae infection. Furthermore, there was physiological interaction between GbCML45 and its close homologue GbCML50 by using yeast two-hybrid and bimolecular fluorescence assays, and both proteins enhanced cotton resistance to V. dahliae infection in a Ca2+-dependent way in a knockdown study. Detailed investigations indicated that several defence-related pathways, including salicylic acid, ethylene, reactive oxygen species and nitric oxide signalling pathways, as well as accumulations of lignin and callose, are responsible for GbCML45- and GbCML50-modulated V. dahliae resistance in cotton. These results collectively indicated that GbCML45 and GbCML50 act as positive regulators to improve cotton Verticillium wilt resistance, providing potential targets for exploitation of improved Verticillium wilt-tolerant cotton cultivars by genetic engineering and molecular breeding.

Exploring Potential Surrogate Systems for Studying the Early Steps of the Sporisorium scitamineum Pathogenesis.

Despite its global importance as a primary source of table sugar and bioethanol, sugarcane faces a significant threat to its production due to diseases. One of these diseases, sugarcane smut, involves the emergence of a whip-like structure from the host apical shoot. The slow onset of this pathogenesis is the most substantial challenge for researchers to investigate the molecular events leading to resistance or susceptibility. In this study, we explored the early interaction between the smut fungus Sporisorium scitamineum and foliar tissues of the model plants Arabidopsis thaliana and Nicotiana benthamiana. Upon inoculation with the fungus, A. thaliana showed a compatible reaction, producing lesions during fungus colonization, whereas N. benthamiana showed signs of nonhost resistance. In addition, we propose a sugarcane detached leaf assay using plants cultivated in vitro to reveal sugarcane smut response outcomes. We used two sugarcane genotypes with known contrasting reactions to smut in the field. Although there is no evidence of sugarcane smut fungus infecting host leaves naturally, the sugarcane detached leaf assay enabled a rapid assessment of disease outcomes. Different symptoms in the detached leaves after inoculation distinguished smut-susceptible and smut-resistant sugarcane genotypes. Microscopic observations and gene expression analysis of S. scitamineum candidate effectors confirmed the fungal growth and its restriction on the compatible and incompatible interactions, respectively. These findings offer new prospects into the disease phenotyping of S. scitamineum, which could greatly expedite the comprehension of the initial stages of the pathogenesis and predict smut resistance in sugarcane genotypes.

Nitrogen-modulated effects of the diazotrophic bacterium Cupriavidus taiwanensis on the non-nodulating plant Arabidopsis thaliana

Nitrogen-modulated effects of the diazotrophic bacterium Cupriavidus taiwanensis on the non-nodulating plant Arabidopsis thaliana

Regulation of seed dormancy by histone post-translational modifications in the model plant Arabidopsis thaliana.

Plants synchronize their growth and development with environmental changes, which is critical for their survival. Among their life cycle transitions, seed germination is key for ensuring the survival and optimal growth of the next generation. However, even under favorable conditions, often germination can be blocked by seed dormancy, a regulatory multilayered checkpoint integrating internal and external signals. Intricate genetic and epigenetic mechanisms underlie seed dormancy establishment, maintenance, and release. In this review, we focus on recent advances that shed light on the complex mechanisms associated with physiological dormancy, prevalent in seed plants, with Arabidopsis thaliana serving as a model. Here, we summarize the role of multiple epigenetic regulators, but with a focus on histone modifications such as acetylation and methylation, that finely tune dormancy responses and influence dormancy-associated gene expression. Understanding these mechanisms can lead to a better understanding of seed biology in general, as well as resulting in the identification of possible targets for breeding climate-resilient plants.

Apo-siderophores promote growth of iron-deficient Arabidopsis plants by mobilizing iron from roots to shoots and reducing oxidative stress in roots

Iron (Fe) is an essential micronutrient for most organisms that is, however, poorly bioavailable in the soil. Acquiring this element is therefore a major issue for both plants and microorganisms. Bacteria acquire Fe by secreting siderophores that chelate the ferric ion with a high affinity and that can contribute to Fe nutrition in plants, under certain conditions including stressful ones. Our previous work has shown that pyoverdine, a siderophore purified from a beneficial Pseudomonas sp., leads to plant growth stimulation when supplied in its Fe-free form (apo-pyoverdine/apopyo) to Arabidopsis thaliana plants grown hydroponically under Fe-deficient conditions. To better understand siderophore-mediated growth promotion, we studied the impact of an apo-siderophore with a different structure from pyoverdine, deferoxamine (DFO), on the same model. Here we show that growth stimulation is linked to the ability of siderophores to chelate Fe, as DFO also promotes growth after 3 to 6 days when provided at 25 µM to 4-week-old A. thaliana plants starved for Fe for 1 to 7 days. The extent to which the siderophore stimulates root and shoot growth depends on the amount of Fe stored in the roots prior to the addition of DFO, and likely involves the remobilization of Fe from the roots to the shoots. The promotion of root growth by DFO does not appear to depend on coumarin production or secretion, but is associated with an increase in the expression of genes of the HOMOLOG OF BEE2 INTERACTING WITH IBH1 (HBI1)-dependent brassinosteroid signaling pathway. DFO stimulates lateral root elongation concomitant with a significant decrease in hydrogen peroxide (H2O2) and oxidized glutathione levels and a decrease in stress-related gene expression in roots. In addition, DFO decreases the expression of the UPBEAT (UPB1) gene involved in H2O2-mediated root growth inhibition, and thus lifts the inhibition of the expression of its target genes, the class III peroxidases that stimulate root growth. Overall, this work indicates that growth promotion by apo-siderophores in an iron-poor environment is likely linked to their ability to induce a stronger response to Fe deficiency while decreasing oxidative stress in roots, thus stimulating Fe remobilization from root Fe pools to shoots and promoting secondary root growth.

Functional and regulatory diversity of homeobox-leucine zipper transcription factors BnaHB6 under dehydration and salt stress in Brassica napus L.

The plant-specific homeodomain-leucine zipper I subfamily is involved in the regulation of various biological processes, particularly growth, development and stress response. In the present study, we characterized four BnaHB6 homologues from Brassica napus. All BnaHB6 proteins have transcriptional activation activity. Structural and functional data indicate the complex role of BnaHB6 genes in regulating biological processes, with some functions conserved and others diverged. Transcriptional analyzes revealed that they are induced in a similar manner in different tissues but show different expression patterns in response to stress and circadian rhythm. Only the BnaA09HB6 and BnaC08HB6 genes are expressed under dehydration and salt stress, and in darkness. The partial transcriptional overlap of BnaHB6s with the evolutionarily related genes BnaHB5 and BnaHB16 was also observed. Transgenic Arabidopsis thaliana plants expressing a single proBnaHB6::GUS partially confirmed the expression results. Bioinformatic analysis allowed the identification of TF-binding sites in the BnaHB6 promoters that may control their expression under stress and circadian rhythm. ChIP-qPCR analysis revealed that BnaA09HB6 and BnaC08HB6 bind directly to the promoters of the target genes BnaABF4 and BnaDREB2A. Comparison of their expression patterns in the WT plants and the bnac08hb6 mutant showed that BnaC08HB6 positively regulates the expression of the BnaABF4 and BnaDREB2A genes under dehydration and salt stress. We conclude that four BnaHB6 homologues have distinct functions in response to stress despite high sequence similarity, possibly indicating different binding preferences with BnaABF4 and BnaDREB2A. We hypothesize that BnaC08HB6 and BnaA09HB6 function in a complex regulatory network under stress.

Cytokinin and MAX2 signaling pathways act antagonistically in drought adaptation of Arabidopsis thaliana

Understanding the mechanisms, especially those associated with phytohormones, of plant drought adaptation is crucial for sustaining agricultural production in the era of climate change. Arabidopsis histidine kinases (AHKs), an integral part of the cytokinin signaling pathway, and more axillary growth 2 (MAX2), a key component of the strigolactone and karrikin signaling pathways are reported to act as negative and positive regulators, respectively, in plant adaption to drought. However, the potential interaction between these singaling pathways in plant drought adaptation is not fully understood. To address this query, we assessed drought tolerance levels and associated phenotypic and physiological traits of the max2 single mutant, ahk2 ahk3 double mutant, ahk2 ahk3 max2 triple mutant, and wild-type (WT) Arabidopsis thaliana plants. Our findings revealed a distinct hierarchy in drought tolerance among these genotypes, as indicated by the differences in plant growth and stress survival rates. Specifically, the max2 mutant displayed the lowest drought tolerance level, followed by WT, ahk2 ahk3 max2, and ahk2 ahk3 plants. Additionally, the observed changes in leaf relative water content, leaf surface temperature, and cuticle formation were coherently aligned with the observed hierarchy of drought tolerance levels. Under drought conditions, the max2 mutant exhibited higher oxidative stress and membrane damage, as evidenced by increased levels of reactive oxygen species (ROS), malondialdehyde, and electrolyte leakage. In contrast, the ahk2 ahk3 and ahk2 ahk3 max2 mutants showed low and intermediate levels, respectively, for these parameters. The max2 mutant displayed reduced sensitivity, whereas ahk2 ahk3 and ahk2 ahk3 max2 mutants demonstrated high and intermediate sensitivities, respectively, to exogenous abscisic acid (ABA) treatments. Additionally, the expression analysis of several genes associated with the investigated drought tolerance-related traits showed a positive correlation between the transcript levels and corresponding trait(s) in both mutant and WT plants under drought conditions. Our results collectively indicate the presence of an antagonistic interaction between AHK and MAX2 signaling pathways in plant drought adaptation, impacting ABA responsiveness, leaf water retention, cuticle development, and ROS homestasis. The findings of this study provide a valuable foundation for developing agricultural methods to improve plant drought resilience.

Heterologous expression of the maize transcription factor ZmbHLH36 enhances abiotic stress tolerance in Arabidopsis

Basic helix-loop-helix (bHLH) transcription factors are widely distributed in eukaryotes, and in plants, they regulate many biological processes, such as cell differentiation, development, metabolism, and stress responses. Few studies have focused on the roles of bHLH transcription factors in regulating growth, development, and stress responses in maize (Zea mays), even though such information would greatly benefit maize breeding programs. In this study, we cloned the maize transcription factor gene ZmbHLH36 (Gene ID: 100193615, GRMZM2G008691). ZmbHLH36 possesses conserved domains characteristic of the bHLH family. RT-qPCR analysis revealed that ZmbHLH36 was expressed at the highest level in maize roots and exhibited different expression patterns under various abiotic stress conditions. Transgenic Arabidopsis (Arabidopsis thaliana) plants heterologously expressing ZmbHLH36 had significantly longer roots than the corresponding non-transgenic plants under 0.1 and 0.15 mol L−1 NaCl treatment as well as 0.2 mol L−1 mannitol treatment. Phenotypic analysis of soil-grown plants under stress showed that transgenic Arabidopsis plants harboring ZmbHLH36 exhibited significantly enhanced drought tolerance and salt tolerance compared to the corresponding non-transgenic plants. Malondialdehyde contents were lower and peroxidase activity was higher in ZmbHLH36-expressing Arabidopsis plants than in the corresponding non-transgenic plants. ZmbHLH36 localized to the nucleus when expressed in maize protoplasts. This study provides a systematic analysis of the effects of ZmbHLH36 on root growth, development, and stress responses in transgenic Arabidopsis, laying a foundation for further analysis of its roles and molecular mechanisms in maize.

A prion-like domain is required for phase separation and chloroplast RNA processing during cold acclimation in Arabidopsis.

Arabidopsis (Arabidopsis thaliana) plants can produce photosynthetic tissue with active chloroplasts at temperatures as low as 4°C, and this process depends on the presence of the nuclear-encoded, chloroplast-localized RNA-binding protein CP29A. In this study, we demonstrate that CP29A undergoes phase separation in vitro and in vivo in a temperature-dependent manner, which is mediated by a prion-like domain (PLD) located between the two RNA recognition motif domains of CP29A. The resulting droplets display liquid-like properties and are found near chloroplast nucleoids. The PLD is required to support chloroplast RNA splicing and translation in cold-treated tissue. Together, our findings suggest that plant chloroplast gene expression is compartmentalized by inducible condensation of CP29A at low temperatures, a mechanism that could play a crucial role in plant cold resistance.

A cyclic nucleotide-gated channel gene HcCNGC21 positively regulates salt and drought stress responses in kenaf (Hibiscus cannabinus L.)

Cyclic Nucleotide-Gated Channels (CNGCs) serve as Ca2+ permeable cation transport pathways, which are involved in the regulation of various biological functions such as plant cell ion selective permeability, growth and development, responses to biotic and abiotic stresses. At the present study, a total of 31 CNGC genes were identified and bioinformatically analyzed in kenaf. Among these genes, HcCNGC21 characterized to localize at the plasma membrane, with the highest expression levels in leaves, followed by roots. In addition, HcCNGC21 could be significantly induced under salt or drought stress. Virus-induced gene silencing (VIGS) of HcCNGC21 in kenaf caused notable growth inhibition under salt or drought stress, characterized by reductions in plant height, stem diameter, leaf area, root length, root surface area, and root tip number. Meanwhile, the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) were significantly decreased, accompanied by reduced levels of osmoregulatory substances and total chlorophyll content. However, ROS accumulation and Na+ content increased. The expression of stress-responsive genes, such as HcSOD, HcPOD, HcCAT, HcERF3, HcNAC29, HcP5CS, HcLTP, and HcNCED, was significantly downregulated in these silenced lines. However, under salt or drought stress, the physiological performance and expression of stress-related genes in transgenic Arabidopsis thaliana plants overexpressing HcCNGC21 were diametrically opposite to those of TRV2-HcCNGC21 kenaf line. Yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays revealed that HcCNGC21 interacts with HcAnnexin D1. These findings collectively underscore the positive role of HcCNGC21 in plant resistance to salt and drought stress.