Abstract Background Eucalyptus, a widely cultivated woody plant, is susceptible to a diverse array of pests and diseases, leading to reduced yields and economic losses. Traditional breeding methods are very time-consuming; therefore, plant genetic engineering has emerged as a promising approach for plant pathogen management. However, the genetic transformation system of eucalyptus is still in its early stages of development, while studies on transgenic eucalyptus and its disease resistance genes are limited. The SWAP70 gene has been shown to play a crucial role in the defense response of Arabidopsis thaliana and rice. In this study, the model plant A. thaliana was selected for genetic transformation. The aim was to enhance the expression of the EuSWAP70 gene derived from Eucalyptus grandis, and other disease resistance genes by utilizing an artificial GWSF promoter. Results The results showed that the EuSWAP70 gene was successfully transformed into A. thaliana, and the PCR assay confirmed the presence of the EuSWAP70 gene in transgenic Arabidopsis plants. The gray mold resistance of the EuSWAP70 transgenic Arabidopsis plants under GWSF and CaMV35S promoters was evaluated against Botrytis cinerea infection. After gray mold infection, Arabidopsis plants were ranked by leaf pore area percentage: wildtype > CaMV35S-EuSWAP70 > GWSF-EuSWAP70. The transgenic plants showed stronger gray mold resistance, and the GWSF-EuSWAP70 transgenic plants were stronger than the CaMV35S-EuSWAP70 transgenic plants.

Abstract The ability to acclimate to changing environmental conditions is essential for the fitness and survival of plants. Not only are seasonal differences challenging for plants growing in different habitats but, facing climate change, the likelihood of encountering extreme weather events increases. Previous studies of acclimation processes of Arabidopsis thaliana to changes in temperature and light conditions have revealed a multigenic trait comprising and affecting multiple layers of molecular organization. Here, a combination of experimental and computational methods was applied to study the effects of changing light intensities during cold acclimation on the central carbohydrate metabolism of Arabidopsis thaliana leaf tissue. Mathematical modeling, simulation and sensitivity analysis suggested an important role of hexose phosphate balance for stabilization of photosynthetic CO2 fixation. Experimental validation revealed a profound effect of temperature on the sensitivity of carbohydrate metabolism.

Abstract Background The major floral scent compounds of Arabidopsis thaliana flowers are terpenes. Although A. thaliana is generally considered to be a self-pollinating plant, there are natural variation in terpene volatile emission from flowers. However, the genetic mechanisms underlying the natural variation in Arabidopsis floral scents remain limited. Results Here, we screened 116 natural accessions of A. thaliana and observed a substantial variability in the levels of terpene emission across these accessions. A genome-wide association study (GWAS) uncovered a genomic region associated with the observed variability in myrcene, one of monoterpene compounds. We then performed high-throughput genetic mapping using two representative accessions: Col-0 and Fr-2, which emit low and large amounts of floral terpenes, respectively. Next-generation mapping and RNA sequencing analyses revealed that the natural premature stop codon of CYP706A3 of Fr-2, located at the 98th codon, confers high emission of sesquiterpene from flowers. We also found an independent mutation of CYP706A3 of Np-0 in different position, leading to increased sesquiterpene emission. Interestingly, the expression levels of defense-related genes in Fr-2 were lower than those in Col-0 flowers, which suggests that terpene volatiles are potentially linked to floral defense. Conclusions The natural variation in Arabidopsis floral scent emission was partially explained by one natural allele of CYP706A3. Since some natural accessions harboring a functional allele of CYP706A3 still emit the large amount of floral sesquiterpene, it is possible that rare variants located on other loci increase scent emission.

There is an increasing need to find sustainable alternatives to conventional agrochemicals to reduce biotic stress in crops. One possible strategy is based on promoting the innate defences of plants by stimulating their immune system. The plant immune system relies on the perception of molecules, which trigger a cascade of biochemical responses known as pattern-triggered immunity (PTI). This study investigated the potential of marine macroalgal cell wall components to be perceived by plants, act as elicitors of plant immune responses and induce disease resistance.Cell walls of green, red, and brown algae species were chemically fractionated, and the research focused on testing their ability to induce immune responses in Arabidopsis thaliana. Different PTI hallmarks were tested, including H2O2 production, mitogen-activated protein kinases (MAPKs) phosphorylation, and defence gene expression analysis. The results showed that the CaCl2-extracted fraction was particularly efficacious in inducing H2O2 production. As the CaCl2 fraction of all phylogenetic groups also triggered additional immune responses, its ability to protect Arabidopsis against the bacterial pathogen Pseudomonas syringae was evaluated, confirming that certain CaCl2 fractions successfully provided resistance to the pathogen. The monosaccharide and glycosidic linkage analysis of these fractions pointed to some specific algal cell wall glycans (e.g. porphyrans and fucoidans) that could contribute to the immunostimulatory capacity, thereby paving the way for the identification of distinct structures with potential agrobiological applications.

Abstract A strain of Rhodococcus ruber was isolated from the rhizosphere of Spartina alterniflora. The VOCs released by this strain effectively promote the growth of Arabidopsis thaliana and inhibit several plant pathogenic fungi, including Bipolaris sorokiniana, Cryphonectria parasitica, Fusarium oxysporum, Fusarium pseudograminearum, and Plectosphaerella cucumerina. SPME/GC–MS analysis revealed that the strain produces dimethyl disulfide (DMDS) and dimethyl trisulfide (DMTS), with DMDS being the predominant component of the volatile organic compounds (VOCs). It was observed that the growth of A. thaliana was enhanced under fumigation with DMDS and DMTS. Furthermore, these compounds effectively inhibited the aforementioned plant pathogenic fungi, with DMTS demonstrating a lethal effect on plant pathogenic fungi. Previous studies have confirmed that DMDS and DMTS promote the growth of A. thaliana. In this study, we found that DMTS could significantly enhance plant growth and inhibit plant pathogenic fungi even at low dosages. Transcriptome analysis indicated that the growth-related genes of A. thaliana were significantly upregulated in response to treatment with VOCs from R. ruber. Additionally, VOCs induced changes in multiple plant defense response genes and promoted the C4 pathway.

Abstract Histone acetylation is a key epigenetic modification involved in plant development. Although histone deacetylase inhibitors (HDACi) are commonly studied in human diseases, their role in regulating histone deacetylation in plants remains unclear. This study explores the function of Citronellol, a volatile small molecule, as a plant-derived HDACi using Arabidopsis thaliana (L.) Heynh (A. thaliana) as a model. Citronellol at concentrations of 3 and 6 mM enhanced both root development and aboveground growth. Enzyme activity assays, molecular docking, and molecular dynamics simulations showed that Citronellol binds to specific residues (PHE:64, ARG:65, MET:1, and ILE:214) of the histone deacetylase AtSRT1 in Arabidopsis, inhibiting its activity and elevating H3K9ac levels. Integrated RNA-seq and ChIP-seq analyses revealed that Citronellol increased the expression of genes linked to growth and development, including ATCTH, CPL3, IBR5, TCP4, and KUA1, through enhanced histone acetylation and activation of plant hormone signaling pathways. These findings provide new insights into the epigenetic regulation of plant growth by Citronellol, identifying it as a novel HDACi. Citronellol could serve as an effective plant growth regulator, offering valuable applications for agricultural development.  Graphical Abstract

<i>Albugo</i> spp. are biotrophic parasites that cause white rust in Brassicaceae species, with significant crop losses. The generalist <i>A. candida</i> and the specialist <i>A. laibachii</i> infect <i>Arabidopsis thaliana</i>, and the pathosystem Albugo–Arabidopsis is a model for research in molecular genetics of plant–pathogen interactions. The occurrence of infection by Albugo in wild populations of Arabidopsis and data on the genetics of resistance-susceptibility are compatible with a hypothesis of host–pathogen coevolution. However, the negative impact of Albugo infection on Arabidopsis—a requirement for coevolution—has not been shown under field conditions. To address this question, we analysed the demography and the dynamics of Albugo infection in a wild Arabidopsis population in central Spain and measured plant fitness-related traits. Infection increased mortality by 50%, although lifespan, the fraction of plants that reproduced and seed production were reduced only in plants from the spring cohorts. Despite these negative effects, simulations of demographic dynamics showed that the population growth rate remained unaffected even at unrealistically high infection incidences. The lack of negative effects in autumn–winter cohorts suggests compensatory mechanisms in longer-lived plants. Results support the hypothesis of Albugo–Arabidopsis coevolution.

Abstract Background Chromatin higher-order structure plays an important role in genome stability maintenance and gene transcriptional regulation; however, the dynamics of the three-dimensional (3D) chromatin in male gametophytes during the two rounds of mitosis remains elusive. Results Here, we use the optimized single-nucleus and low-input Hi-C methods to investigate changes in 3D chromatin structure in four types of male gametophyte nucleus at different stages. The reconstructed genome structures show that microspore nuclei develop towards two different directions. Although the 3D chromatin organization in generative nuclei is similar to that in microspore nuclei, vegetative nuclei lose chromosome territories, display dispersed centromeres, and switched A/B compartments, which are associated with vegetative specific gene expression. Additionally, we find that there is an active transcriptional center in sperm nuclei, emphasizing the transcription in Arabidopsis sperm is not completely inhibited despite the chromosomes being condensed. Conclusions Our data suggest that the special 3D structures of vegetative and sperm nuclei contribute to cell type-specific expression patterns.

peer reviewed | The increasing use of synthetic chemical herbicides has resulted in environmental, human and animal health issues. This has also led to the development of herbicide resistance in weed populations. The use of essential oils (EOs) can contribute to the development of effective, eco-friendly and nature-based alternatives to these chemical products due to their phytotoxicity and multisite action. Our study aimed to evaluate the proteomic response of Arabidopsis thaliana (A. thaliana) leaves to the application of a cinnamon essential oil (CEO) emulsion. The results showed that the application of CEO emulsion at a concentration of 6% severely impacted the proteomic profile of A. thaliana, especially for membrane proteins and those involved in the photosynthesis process. Interestingly, 40 proteins were identified and listed as the most differentially accumulated proteins in the leaves of A. thaliana. CEO decreased the expression of all the proteins associated with catabolism and anabolism processes while simultaneously increasing the expression levels of proteins involved in the response to oxidative stress. Overall, these findings allowed us to obtain a global view of the proteome response to CEO, opening promising perspectives for the development of natural herbicides, especially given the low probability of developing resistant weed populations.

Background: Arabidopsis thaliana is the most widely used plant organism as a study model, due to its short life cycle and small genome. Among the most used accessions, the Columbia (Col-0) ecotype is widely used for molecular and genetic research, however the physiological response of this model plant to abiotic factors is relatively unknown. Objective: Given its relevance in studying gene functionality, it is essential to understand its physiology and morphology under individual stress conditions: water deficit stress (WDS), thermal shock (50 °C for 2 hours), and under the combined effect of both stress types (WDS + 50 °C for 2 hours). Methodology: 75-day-old A. thaliana Col-0 plants were used for the 3 stress treatments: 14d of WDS, 50 °C/2 h, and 14d WDS + 50 °C/2 h. The survival percentage, water potential, electrolyte leakage, PSII status, and gas exchange were evaluated. Results: A. thaliana plants exhibited susceptibility to prolonged levels of stress, demonstrating different physiological mechanisms to cope with individual and combined stresses. The analysis of the photochemical state of PSII indicated that Arabidopsis is more vulnerable to the 50 °C/2 h stress and to the combined WDS + 50 °C/2 h stress, than to water deficit stress. The WDS + 50 °C/2 h treatment caused greater membrane damage, more negative water potential, and lower gas exchange compared to the individual stress. Implications: This system is proposed for future molecular analyses involving the overexpression of cloned transcription factor genes from tolerant species, with the aim of extrapolating these findings to commercially relevant crops. Conclusion: The differential response observed under different types of stress in this model plant, may facilitate the elucidation of underlying molecular mechanisms, which should be a central focus in future research aiming to increase resilience to climate change factors in commercially important agricultural crops.