Little is known about the contributions of DNA methylation/demethylation to plant aging and senescence. We used Arabidopsis thaliana to study how increasing age of an annual plant species influences DNA methylation. Based on methylation-sensitive DNA fragmentation assay, it could be concluded that aging A. thaliana was accompanied by DNA demethylation. Bisulfite sequencing reveals that cytosine methylation within the Actin2 3' untranslated region and internal transcribed spacer with 5.8S rRNA (ITS1-5.8SrRNA-ITS2) DNA regions decreased with A. thaliana growth and aging. We show that transcription of methyltransferase genes, chromomethyltransferase AtCMT3 and methyltransferse AtMETI, significantly decreased during development and aging of the A. thaliana plants, whereas expression of demethylase genes - repressor of silencing AtROS1, demeter AtDME, and demeter-like AtDML2 and AtDML3 - increased at least at some stages of plant development. The data obtained in the present study suggest that plant DNA regions may undergo demethylation during plant aging via reduction of DNA methylation processes and activation of active DNA demethylation.

The cuticle is the first physical barrier between the plant and the outer environment. The cuticle is no longer viewed as a rigid "inert sealer". Components of the cuticle were found to be responsive in their function and chemical composition to environmental signals. Cuticle creation is energy-consuming and complicated. Thus, cuticle composition and renewal dynamics are precisely regulated. Activated plant immunity is also energy "expensive". We briefly summarised our knowledge of the involvement of cuticle in plant-microbe interactions. Changes in cuticle amount and composition affect plant resistance to pathogens and treatment with cutin monomers triggers plant immunity. However, our knowledge about the effects of activated plant immunity on cuticle is scarce. We hypothesise that activated immunity influences cuticle dynamics. Our in-silico gene expression analysis revealed that cuticle biosynthetic genes are modulated under conditions simulating activated immunity. The analysis indicates that the cuticle is not just a rigid component of a plant reaction to the pathogen attack. Strengthening of the cuticle could prevent pathogen penetration. However, inhibition of cuticle production could save the energy needed for plant immunity. We propose questions which should be addressed in future research. Answering them would lead to a better understanding of plant defence against pathogens.

Within the last two decades, plant viral vectors have emerged as an excellent tool for the expression of foreign peptides and proteins. Virus particles carrying foreign antigenic epitopes present some interesting advantages for vaccine design and other applications. This review covers recent advances in the use of some typical plant viruses with helical particles that present heterologous peptides with particular emphasis on particles derived from the Potato virus X (PVX) and its uses.

Background: Idesia polycarpa var. vestita Diels is an oil-bearing woody plant of significant economic value. Aims: To accelerate the propagation of its elite germplasm, this study aimed to establish an efficient and stable in vitro rapid propagation system using one-year-old stem segments from elite plants. Methods: Young stem explants were disinfected with 75% ethanol for 40 s, followed by 0.1% HgCl₂ for 6 min. MS or 1/2 MS served as basal media, and various combinations of plant growth regulators were tested for axillary bud induction, proliferation, and rooting. Results: The optimal disinfection protocol yielded a 38.10% survival rate. The best axillary bud induction medium was MS + 1.5 mg/L 6-BA + 0.05 mg/L NAA + 0.08 mg/L TDZ, achieving 100% induction. For proliferation, MS + 1.5 mg/L 6-BA + 0.06 mg/L NAA + 0.01 mg/L TDZ (proliferation coefficient 5.81) was optimal. Rooting was best with 1/2 MS + 0.3 mg/L IAA + 0.1 mg/L NAA (100% rooting, 14 roots/plant). Conclusions: This study established a reliable micropropagation system for Idesia polycarpa var. vestita, providing technical support for the efficient production of high-quality seedlings.

Flavonoids are a class of phenolic compounds that are widely distributed in nature. They have a variety of physiological and pharmacological activities. They exist in free form or in the form of glycosides. The glycosylation occurs by glycosyltransferases, which is a common modification of plant secondary metabolites and the last step of their biosynthesis. Glycosylation can increase the diversity of the structure and function of flavonoids, and is currently a research hotspot. Based on the classification of flavonoids, this paper describes and summarizes the biotransformation and characteristics of glycosylation modification of flavonoids with different structural types, and describes the effects of enzymatic glycosylation using different types of glycosyltransferases on the biological activity and function of flavonoids depending on sugar connection position, sugar quantity, and type. This paper provides a reference for the development and application of flavonoids glycosylation and glycosyltransferases and also opens up a new direction for plant breeding.

The coastal areas of western Taiwan feature acidic and saline soils with low fertility. Sodium bicarbonate (NaHCO₃), produced readily by carbon capture and storage technologies, could be suitable for the neutralization of acidic soils, but its effects on plant growth and the ability of Bacillus subtilis var. natto to confer salinity tolerance remain unclear. In this study, we examined the potential of sodium bicarbonate and B. subtilis var. natto (NTU18) to improve the growth of tobacco (Nicotiana tabacum L.) under salt stress conditions. We found that salt stress was the main factor affecting tobacco growth, resulting in shorter roots and shoots, a reduced leaf area and leaf number, and clustered dark green leaves. The addition of sodium bicarbonate exacerbated the symptoms of salinity stress. Inoculating the soil with B. subtilis did not enhance salinity tolerance, but intriguingly it increased shoot and root growth under normal conditions and in the presence of sodium bicarbonate. The mechanism of growth promotion mediated by the bacteria is unknown and should be investigated in more detail.

Tetracentron sinense Oliv, the only tall deciduous tree in the family Tetracentraceae, is listed as a national second-grade key protected plant in China. To reveal the effect of associated species, irradiance, and altitudes on photosynthetic capacity of T. sinense, photosynthetic physiological characteristics of T. sinense and its associated species Acer pictum and Pterocarya stenoptera were measured by a Li-6400 portable photosynthetic meter. The light saturation point (LSP), the maximum net photosynthetic rate of the P_N-PAR (P_Nmax), carboxylation efficiency (CE), the maximum net photosynthetic rate of the P_N-CO₂ (P^*_Nmax), carbon dioxide compensation point (CCP) and light respiration rate (R_p) of T. sinense in forest gap (FG) were higher than those in forest edge (FE) and understory (US). In FE, the net photosynthetic rate (P_N), light compensation point (LCP), LSP, P^*_Nmax of T. sinense were lower than those of Pterocarya stenoptera, while the LSP, P_Nmax, and saturation point of carbon dioxide (C_iast) of T. sinense in US were lower than those of Acer pictum and Pterocarya stenoptera. The specific leaf area (SLA) of T. sinense decreased with reduction in the irradiance. With increasing altitude, the P_Nmax, LSP, and SLA of young individuals of T. sinense (YT) increased; the LCP of YT or the LSP of mature individuals of T. sinense (MT) increased first and then decreased. The results showed that 1) the photosynthetic capacity and adaptability of T. sinense were better in FG than that in FE and US; 2) the photosynthetic capacity of T. sinense in FE and US was weaker than that of its associated species, and its ecological range of light adaptation was also narrower than that of its associated species, placing T. sinense at a competitive disadvantage, which may be one of the important reasons for its poor regeneration; and 3) the environmental conditions at higher altitude can contribute to the growth and survival of T. sinense. Therefore, active artificial intervention should be undertaken to expand area of forest gap for T. sinense and transplant its seedlings to higher altitude to promote growth and population regeneration of T. sinense.

The “Centre for Experimental Plant Biology”, a joint project of the Institute of Experimental Botany of the Czech Academy of Sciences and CEITEC (represented by Mendel and Masaryk Universities), focused on elucidating  the mechanisms of plant responses to abiotic and biotic stresses and their combinations at the cellular level, in intact plants during vegetative and reproductive stages, and fruit development. The consortium demonstrated the importance of shared research facilities, complementary approaches, and knowledge exchange, addressing demanding questions  in plant biology. The consortium made breakthrough in plant-pathogen interactions, including identification of  exocyst-syntaxin cooperation in non-host resistance. The results confirmed the fundamental role of phytohormones in stress responses, including negative correlation of leaf bioactive gibberellins with drought stress, and the role of cytokinins in ROS homeostasis, sulphur metabolism, and heat stress responses, including volatile emission. Molecular analyses revealed expansin-mediated cell wall remodelling, brassinosteroid-mediated regulation of root growth through PIN2, the role of ALBA and LARP6C proteins in pollen development under abiotic stress, and heat stress impact on fertilization rate, embryo and seed development. Gene Set Enrichment and RNA-Seq analyses allowed to identify crucial genes involved in the apple scab resistance network. The main results obtained during the five-year project are summarised here.

Garlic mustard (Alliaria petiolata) is an herbaceous biennial plant native to Europe. In Ukraine, in addition to becoming a serious invader, garlic mustard can serve as a host to several viruses, which may affect agricultural crops. In view of this, the purpose of the study was to identify the virome of garlic mustard growing in Ukraine. Plant samples collected in Kyiv regions were tested for the presence of cucumber mosaic virus (CMV), turnip mosaic virus (TuMV), turnip yellow mosaic virus (TYMV), watermelon mosaic virus II (WMV), and turnip crinkle virus (TCV) by serological and/or molecular methods. According to the results found in the present study, symptomatic A. petiolata obtained in 2021 were infected with CMV (60%), TuMV (20%), or co-infected with CMV + TuMV (20%). TYMV, WMV II, and TCV were not detected in any of the collected samples. The cDNA fragments encoded the coat protein (CP) gene of CMV and TuMV were sequenced and named as CMV-Ap and TuMV-Ap, respectively. In phylogenetic analysis, the CMV-Ap closely resembled the German isolate MW582807 (Sarracenia sp.), with 99.8% nucleotide identity and belongs to subgroup II of CMV. In the phylogenetic tree, TuMV-Ap clustered with isolates AP017803, AP017764, AP017791, and JQ073722, and represented the highest identity (98.6%) to Iranian isolate IRNTRa9 (AP017803) from Rapistrum rugosum and Turkish isolate TUR49 (AP017872) from Raphanus raphanistrum. The sequences of CMV-Ap and TuMV-Ap were deposited in the GenBank under Accession Numbers MZ540213 and OM799323, respectively. The results obtained in the study indicate the important role of infected garlic mustard as alternative host and natural reservoir of CMV and TuMV from which these economically important viruses can spread to other wild and cultivated plants. This is the first molecular evidence of TuMV infection in A. petiolata from Ukraine.

Owing to cold resistance and a lack of heat resistance in spinach (Spinacea oleracea L.), heat is the primary constraint that limits its production in summer. This study examined the auxiliary effects of spinach rhizosphere microbes on improving the heat resistance of spinach. A strain isolated from the rhizosphere soil of heat-stressed spinach was identified as Bacillus subtilis and designated B. subtilis BE-L21. It produces indoleacetic acid, amylase, and protease and solubilizes phosphorus. Further research revealed that spinach seedlings inoculated with this strain of B. subtilis had increased content of soluble protein, soluble sugar, and proline that adjusted their osmotic potential. The reducing content of malondialdehyde showed alleviated irreversible damage of spinach plants under heat stress. Also the increased activities of antioxidant enzynes peroxidase, superoxide dismutase, and catalase enhanced the heat resistance of spinach. The results indicate that B. subtilis BE-L21 can contribute to tolerance of spinach seedlings to elevated temperatures by inducing physiological and biochemical changes in the plant.

The present work aimed to evaluate the effect of heat stress on common bean (Phaseolus vulgaris L.) genotypes during the reproductive phase as a function of the inoculation of plants with Bacillus subtilis. The treatments were established by inoculating two strains of B. subtilis (AP-3 and AP-12) and a control. The plants were subjected to heat stress when they reached the reproductive stage, with an increase in temperature to 28/33°C. The duration of the stress period was ten days. Flowering, biochemical, and gene expression evaluations were performed. There was the interaction of B. subtilis AP-3 with the bean cultivar IAC-Imperador, reducing flower abortion, promoting the formation of new flower buds, and increasing the content of proline and guaiacol peroxidase activity in plant tissues. However, there was a reduction of transcription of genes encoding the 1-carboxylic acid-1aminocyclopropane oxidase and ethylene response factors and an increase of the Δ¹-pyrroline-5-carboxylate synthetase1 gene. These results suggest that B. subtilis may modulate some metabolic pathways in response to high-temperature stress during the reproductive phase of the common bean. This also confirms that Bacillus strains represent a useful option to moderate abiotic stresses.

The Czech Plant Nucleus Workshop 2021 (CPNW2021) took place during mid-September 2021 in Olomouc, Czech Republic. About 80 researchers and students working in the field of plant nuclear and chromosome biology in the Czech Republic gathered together to present and discuss their current research. The meeting revealed many plant models that are used to study plant genomes and their organization, and also a great diversity of topics including epigenetic regulation of gene expression, genome stability, telomere biology, or sex chromosomes. CPNW2021 provided a broad platform for establishing new research contacts and collaborations. Here, we summarize the main research directions and findings presented at the CPNW2021 meeting.

We compared C₃ and CAM (crassulacean acid metabolism) states in Mesembryanthemum crystallinum, a facultative CAM species, with respect to the involvement of phosphoenolpyruvate carboxylase (PEPC) and nitrogen metabolismrelated enzymes in plant response to Botrytis cinerea infection. The enzyme activities were monitored both in pathogeninoculated 2^nd leaf pair and non-inoculated 3^rd leaf pair. The control activities of most studied enzymes were dependent on the mode of photosynthesis. Compared to C₃ plants, those performing CAM exhibited higher PEPC, nitrate reductase (NR), and deaminating glutamate dehydrogenase (NAD-GDH) activities but lower glutamine synthetase (GS) and alanine aminotransferase (ALT) activities. Regardless of the mode of photosynthetic carbon assimilation, the plants responded to infection with enhancement of PEPC and inhibition of NR activities in the inoculated leaves. Whereas the activity of GS remained unaffected, those of all glutamate-yielding enzymes, namely ferredoxin-dependent glutamate synthase (Fd-GOGAT), aspartate aminotransferase (AST), ALT, and aminating glutamate dehydrogenase (NADHGDH) were altered after infection. However, the time-course and extent of the observed changes differed in C₃ and CAM plants. In general, CAM plants responded to infection with an earlier increase in PEPC and Fd-GOGAT activities as well as later inhibition of NR activity. Contrary to C₃ plants, in those performing CAM the activities of PEPC, Fd-GOGAT, NADH-GDH, and AST in the non-inoculated 3^rd leaf pair were similarly influenced by infection as in leaves directly inoculated with the pathogen. This implies that the local infection induced an alteration of carbon/nitrogen status in healthy upper leaves. This reprogramming resulting from changes in PEPC and nitrogen metabolism-related enzymes was C₃- and CAM-specific.

Background: The tomato brown rugose fruit virus (Tobamovirus fructirugosum, ToBRFV) is an emerging tobamovirus that has quickly become a significant obstacle to the production of tomatoes and peppers worldwide. It is now classified as a regulated quarantine pathogen. Effective containment requires rapid, reliable, inexpensive, and safe diagnostic protocols for routine screening in laboratories and production systems.
Aims: We aimed to thoroughly evaluate integrated molecular and serological diagnostic methods for ToBRFV and develop biosafe positive controls suitable for high-throughput and decentralized applications.
Methods: We evaluated the following methods: conventional RT-PCR, one-enzyme RTX-PCR, immunocapture RT-PCR, recombinase polymerase amplification, loop-mediated isothermal amplification with colorimetric detection, Western blotting, dot blot, and tissue blot immunoassay. The non-infectious positive control was prepared using the GoldenBraid 3.0 cloning system. We developed a single-seed assay that enables direct testing of tomato seed stocks.
Results: Among the evaluated molecular methods, RTX-PCR was particularly advantageous due to its minimal sample handling, reduced cost, and ability to bypass RNA extraction. The tissue blot immunoassay enabled high-throughput, low-cost screening of hundreds of samples per day using only basic equipment. Although ToBRFV was frequently detected in seeds harvested from infected plants, no systemic infection was observed in progeny seedlings, confirming the low rate of true vertical transmission. A non-infectious positive control was prepared and successfully employed in molecular methods.
Conclusions: Our findings provide an integrated diagnostic framework combining molecular, serological, and biosafety tools to effectively monitor and contain ToBRFV in commercial production and phytosanitary settings.

By decreasing root 1-aminocyclopropane-1-carboxylate (ACC) content and plant ethylene production, the microbial enzyme ACC deaminase is a widespread beneficial trait of plant growth-promoting rhizobacteria (PGPR), ameliorating ethylene-mediated root growth inhibition. However, relatively little is known about whether bacterial ACC deaminase modulates root architecture and root hair traits. Thus the dwarf tomato (Solanum lycopersicum) cultivar Micro-Tom was inoculated in vitro with Pseudomonas brassicacearum Am3, its ACC deaminase deficient mutant T8-1, a known PGPR strain Variovorax paradoxus 5C-2 or chemically treated with agents that promoted or inhibited ethylene production or sensitivity (Ag⁺, Co²⁺, and ACC). ACC treatment reduced both root elongation and the number of lateral roots, while ethylene inhibitors (Ag⁺, Co²⁺) and V. paradoxus 5C-2 promoted primary root elongation, but differentially affected lateral root length and number. Ag⁺ stimulated lateral root development, while Co²⁺ and V. paradoxus 5C-2 did not. Inoculation with P. brassicacearum Am3 and T8-1 inhibited elongation of the primary and lateral roots at a high inoculum concentration (10⁶ cells cm³). All bacterial strains significantly increased the length and number of root hairs, with these effects more pronounced in P. brassicacearum Am3 than in the mutant T8-1. Treatment with Ag⁺ inhibited root hair formation and elongation, while Co²⁺ had the opposite effects. ACC treatment had no effect on root hair elongation but increased root hair density. While root growth inhibition caused by P. brassicacearum Am3 was independent of ACC deaminase, the promotion of root hair elongation and density by this strain was augmented by ACC deaminase activity. Thus ACC deaminase can modulate the morphological impacts of bacteria on root hair response by affecting plant ethylene content.

Abiotic stress is one of the major challenges facing crop production globally. Abiotic stress resulting from low temperature is a major limitation to crop production, especially in the temperate regions of the world. Cold stress not only influence crop development and reduce yields, but also curtail the efficient distribution of agricultural products worldwide. An understanding of the molecular mechanisms underlying cold stress tolerance is important for the development of strategies to manage crop loss and improve yield. In this review, we explore the major molecular mechanisms involved in plant cold tolerance, including recent discoveries on interrelated gene networks and regulatory mechanisms for cold stress adaptation in crops. Further, we highlight the role of proteomics in the discovery of proteins involved in key signaling pathways, including late embryogenesis-abundant proteins, antifreeze proteins, cold-regulated proteins, heat shock proteins, and pathogenesis-related proteins. The role of these proteins, and their relative abundance in physiological-biochemical reactions, are discussed and key candidate proteins for plant genetic enhancement are suggested.

Background and aims: There appears to be a strong correlation between the rapid proliferation of shrubs in the alpine grassland of the Qinghai-Tibet Plateau and the root exudates of these plants. The dynamics of root exudates during shrub development, however, have been the subject of few investigations. Methods: This work examined Lonicera thibetica, a plant found on the eastern edge of the Qinghai-Tibet Plateau. It focused on the root systems of 5-, 10-, 15-, and 20-year-old L. thibetica plants and how their primary organic acid components changed with the seasons and other circumstances. Results: The findings revealed that the primary components of acid secretion in the roots of L. thibetica were oxalic acid, lactic acid, and tartaric acid; of these, oxalic acid made up over 50% of the total organic acid content. The levels of these organic acids often dropped as shrubs got older, and their seasonal dynamics exhibited a parabolic shift pattern, typically peaking during the robust development stage. According to regression analysis, soil moisture was the primary determinant of the concentration of organic acids produced by alpine shrub roots, suggesting that soil moisture played a crucial role in the secretion process. Conclusions: The physiological dynamics of roots and the mechanisms that regulate them throughout the expansion of alpine shrubs can be better understood thanks to this work.

Background and aims: Tire wear microplastics (TWMs) are emerging environmental contaminants, but their ecological risks to agricultural systems remain poorly understood. Methods: Rice seedlings were exposed to 0, 10, 100, and 1 000 mg L^-1 TWMs for 10 days. Growth parameters, chlorophyll fluorescence, and antioxidant enzyme activities were measured. Results: TWMs promoted growth; exposure to 1 000 mg L^-1 TWMs increased plant height and root length by 8.06% and 57.38%, respectively. Chlorophyll fluorescence analysis revealed that TWMs significantly suppressed rETR_max by 32.53 - 43.62% and altered qP and NPQ. TWMs inhibited Y(NPQ) while enhancing Y(NO) loss, indicating impaired photoprotective dissipation and aggravated photodamage. TWMs also inhibited SOD, POD, CAT, and APX activities in both leaves and roots, with root CAT and APX decreasing by up to 37.35% and 40.34%, reflecting a direct impairment of the antioxidant defense system. Conclusions: Rice seedlings achieve TWM-induced short-term growth at the expense of compromised photosynthetic efficiency and antioxidant defense, leading to an unsustainable compensatory state. This study provides physiological evidence for assessing TWMs phytotoxicity in agricultural systems.

Plant translation elongation factor 1 alpha (EF1A) is both a protein synthesis factor and an important component of plant signal transduction, immune responses, protein trafficking, and apoptosis. However, its role in plant growth and development remains unclear. Herein, a full-length EF1A gene was isolated from banana (Musa acuminata L.) fruit and termed MaEF1A. We found that MaEF1A shared a high sequence identify with respective genes in other plants and the deduced amino acid sequence contained conserved regions of GTP-EFTU, GTP-EFTU-02, and GTP-EFTU-03, as well as two tRNA binding domains and six GTP-binding sites which represent functional domains for protein biosynthesis. MaEF1A protein is mainly localized to the nucleus. MaEF1A was constitutively expressed in different banana organs including developing fruits, and the highest expression was detected in ovary 4 stage. Arabidopsis thaliana L. (ecotype Columbia) was transformed with MaEF1A and four transgenic lines were obtained. Three transgenic lines were selected for further phenotypic analyses. Our findings indicate that overexpressed MaEF1A could greatly enhance plant height, root length, and both rhachis and silique length by promoting cell expansion and elongation. These experiments suggest an important role for MaEF1A in plant growth and development.

Tamarix ramosissima is a deciduous shrub that resides in arid and semi-arid regions. Although of ecological and medicinal values, some Tamarix species are considered invasive as they have dominated the riparian zones of dryland in some parts of the world. Here, the complete chloroplast (cp) genome of T. ramosissima was sequenced and analyzed, showing a size of 156 150 bp and a GC content of 36.5 %. The plastome displayed a typical quadripartite structure, consisting of a pair of inverted repeat (IR) regions of 26 554 bp, separated by a large single copy (LSC) region of 84 795 bp, and a small single copy (SSC) region of 18 247 bp. The cp genome encoded 130 genes, including 85 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. A total of 32 repeat sequences and 64 simple sequence repeat (SSR) were identified in the plastome, and an obvious A/T bias was observed in the majority of the SSRs detected. By comparing the T. ramosissima cp genome with those of the other four Tamaricaceae species, a number of divergence hotspots were identified among these plastomes. Together with SSRs and long repeats identified, these divergence hotspots could be developed as potential molecular markers facilitating species discrimination and evolutionary studies. Using plastome sequences, we re-investigated the phylogenetic relationship among 19 species, and T. ramosissima was found to be a sister of Tamarix chinensis. Taken together, our study provides valuable genomic resources to deepen the understanding of plant photosynthetic mechanism and phylogenomics.

Heat shock and almost all types of stresses associated with oxidative stress are accompanied by heat shock protein (HSP) expression. HSPs are involved in refolding denatured proteins and directing unrepairable proteins for degradation. Thus, under stress conditions, HSPs help to restore cellular balance. However, in virus-infected plants, HSP70 can have both positive and negative effects because viruses usually recruit HSP70. HSP70 can promote the replication and translation of the viral genome, the formation of viral replication complexes, and the propagation of viral particles from cell to cell and throughout the plant. HSP gene silencing in various virus-host plants systems and the comparison of susceptible and resistant species have shown that HSPs70 accelerate the development of infection. Conversely, during the process known as thermotherapy, the temperature increase inhibits viral replication in some host and virus systems. The success of thermotherapy depends not only on the temperature and treatment period or duration but also on the plant species and viral strain. In this review, we discuss the ambiguous role that HSPs70 play during viral infections in plants towards weighing the balance between their positive and negative functions.

Tomato spotted wilt virus (TSWV; species Orthotospovirus tomatomaculae, family Tospoviridae) (Kuhn et al., 2023), is a negative strand RNA-virus containing envelope structures, which makes it unique among plant viruses (de Haan et al., 1991). TSWV ranks among the most destructive plant viruses worldwide. First described in Australia in 1919, TSWV has since attained a global distribution, infecting over 1 000 plant species across more than 85 families, including key agricultural crops such as tomato (Solanum lycopersicum), pepper (Capsicum annuum), groundnut (Arachis hypogaea), and various ornamentals (Parrella et al., 2003; Pappu et al., 2009). Infected plants typically exhibit chlorotic or necrotic spots, wilting, stunted growth, and in severe cases, complete crop failure, resulting in considerable economic losses, particularly in Solanaceous and Asteraceous crops (Roselló et al., 1996; Latham and Jones, 1998).

Small RNAs (sRNAs) are essential components of gene-regulatory networks, which guide plant development and tune it to environmental challenges. Though the past years have witnessed evidences on sRNA importance for stress response, there is scarce data on their involvement in resurrection plant survival under severe drought. Haberlea rhodopensis (hrh) is an angiosperm resurrection species, whose vegetative tissues can tolerate desiccation and recover upon rehydration. In this study, high-throughput sequencing sRNAs indicated a higher complexity of the sRNA population, especially of a 24 nt sRNA category, in the desiccated vegetative tissue of H. rhodopensis compared to unstressed tissues. The cross-species discovery was performed to predict 77 mature microRNAs (miRNAs), most of which were assigned to 23 high-confidence conserved miRNA families in the leaf tissue. Several members of the miR156/157, miR166, and miR399 families were found to be desiccation-responsive. The miR156/157 family members were found up-regulated upon dehydration and down-regulated upon rehydration, while the miR166 and miR399 family members followed an opposite trend of expression. A probable miR156/157 target, orthologous to the SQUAMOSA promoter binding protein-like, was reconstructed in H. rhodopensis based on genomic data available for this species and the closely related Boea hygrometrica. Reverse transcription quantittative PCR analysis confirmed the expression profile of hrh-miR156a-5p and hrh-miR157-5p established by sRNA sequencing and revealed an inverse expression pattern between these miRNAs and their targets in the desiccated tissue. Our study suggests that the miR156/157 and miR399 families are essential for plant survival under severe drought due to their ability to control plant development and growth by modulating transcription factor expression.

PopW, a harpin protein identified from Ralstonia solanacearum, has multiple beneficial effects in plants, promoting plant growth and development, increasing crop yield, and inducing resistance to pathogens. Tobacco plants transformed with popW, the PopW-encoding gene, exhibited a promoted growth rate and enhanced resistance to Tobacco mosaic virus (TMV). Here, it is documented that the transgenic tobacco plants overexpressing popW exhibited a higher resistance to R. solanacearum YN10 infection compared with that of the wild-type plants. In the popW-expressing tobacco lines, an enhanced H2O2 accumulation and hypersensitive reaction (HR) were activated in the inoculated site. In addition, the resistance was accompanied with increased transcripts in numbers of genes related to defense (including HR), reactive oxygen species (ROS) scavenging, and salicylic acid (SA), jasmonic acid (JA), and ethylene (ET) production. These results suggest that popW acted as positive regulator in tobacco resistance against R. solanacearum via modulation of SA-, JA-, and ET-mediated signaling pathways. We report for the first time that the expression of a harpin-encoding gene in vivo improved plant resistance to R. solanacearum.

Nitrogen is an essential nutrient for plants. Different nitrate (NO₃^-)/ammonium (NH₄⁺) ratios have different effects on plant growth. However, the underlying mechanism in Toona sinensis remains unclear. Thus, we determined the effects of five different NO₃^-/NH₄⁺ ratios (16/0, 12/4, 8/8, 4/12, and 0/16, denoted T1, T2, T3, T4, and T5, respectively) in nutrient media on T. sinensis seedling growth. When the nitrogen source was NH₄⁺ alone (T5) or NO₃^- alone (T1), the soluble protein content in the leaves was the lowest. Additionally, the activities of key nitrogen assimilation-related enzymes, such as nitrate reductase (NR), glutamate synthase (GOGAT), and glutamine synthetase (GS), were altered by the NO₃^-/NH₄⁺ ratio. Principal component analysis (PCA) revealed that the T2 treatment was optimal for T. sinensis seedling growth. The NO₃^-/NH₄⁺ ratio regulates nitrogen assimilation at the transcription level, as under high NO₃^- conditions, the expressions of NR, GS, and NADH-GOGAT were high, and nitrate transporter (NRT) family members NRT1, NRT1.1, and NRT1.7 played leading roles in nitrogen transport. However, under low NO₃^- conditions, the level of NRT2.7 increased to ensure nutrient absorption. Our results provide a theoretical basis for understanding how different NO₃^-/NH₄⁺ ratios affect T. sinensis growth.

Image-derived phenotyping at individual plant level can provide more accurate and more comprehensive information than manual measuring for quantitative traits related to canopy growth in field environment. Aims of this study were to: (i) assess smartphone image-derived canopy parameter at early stage of sunflower, and (ii) to evaluate performance of predictive models for morphological and biomass traits related to canopy growth using smartphone image-derived parameter. Original top-view image datasets taken with a smartphone camera were processed, and necessary information was extracted with image analysis software developed using fuzzy c-means clustering algorithm. Canopy cover rate per plant (CCR) was not only the relative value but also image-derived phenotyping feature. CCR were significantly and positively correlated (r ≧ 0.90; **P < 0.01) with plant height, total leaf area per plant, plant dry mass, aboveground plant dry and leaf dry mass, respectively. Ground measured and predicted values from linear regression model for plant height, total leaf area per plant, plant dry mass, aboveground total dry mass, leaf dry mass per plant with CCR showed an accurate prediction with high coefficients of determination (R ) of more than 0.8063, respectively. The present study documented the robustness of predictive models using several metrics.

This study investigated the impacts of acid rain stress on Akebia trifoliata and the mitigation effects of exogenous curcumin (CUR) using integrated physiological, anatomical, and transcriptomic analyses. Acid rain stress significantly decreased chlorophyll content (total chlorophyll by 64.8%), leaf epidermal thickness (upper and lower epidermis by 58.9 and 35.6%), and starch content (by 63.9%), while increasing oxidative stress markers (MDA by 82.6%; ROS production by 345.8%) and content of osmolytes (proline by 64.4%). A. trifoliata counteracted acid rain stress by enhancing superoxide dismutase (SOD) and catalase (CAT) activities, and by modifying leaf anatomical structure (increased mesophyll tissue thickness). CUR application, particularly at 50 μmol/L (CUR50), effectively alleviated damage by maintaining leaf structural integrity and promoting growth recovery. Transcriptomic analysis revealed 993 differentially expressed genes between CUR50-treated vs. acid rain-stressed plants, primarily enriched in the plant hormone signal transduction and phenylpropanoid biosynthesis pathways. These results demonstrate that CUR mitigates acid rain stress through coordinated physiological adaptations and transcriptional reprogramming of stress-responsive pathways. This study provides a theoretical basis for cultivating A. trifoliata and implementing phytoremediation strategies in acid rain-affected regions.

Virus-induced gene silencing (VIGS) is a technological process in which the expression of a plant target gene is down-regulated by inoculating a plant with a recombinant virus-based vector carrying part of the coding sequence of the target gene (Baulcombe, 1999a; Burch-Smith et al., 2004). VIGS uses an RNA silencing-based defence mechanism in which double-stranded RNAs (dsRNAs) of viral origin, as templates, are processed into small interfering RNAs by Dicer-like enzymes. The resulting siRNA is incorporated into an RNA-induced silencing complex, which leads to the degradation of the RNA (viral RNA, mRNA) with sequences complementary to the siRNA. Thus, VIGS utilises foreign plant genes/targets harboured by a viral vector to produce dsRNA, a source of siRNAs that triggers RNA-mediated silencing of the corresponding target gene. VIGS has proven to be a powerful and cost-effective method for functional genomics studies in plants (Rössner et al., 2022).

In natural environments, the growth and development of plants are frequently impeded by a variety of stresses. These can be categorized into biotic stresses, such as those caused by fungi and bacteria, and abiotic stresses, including factors like low temperature, drought, and salinity (Zhu, 2016). These stresses impact plant photosynthesis, osmotic adjustment, and nutrient uptake, thereby inhibiting plant growth and ultimately resulting in a reduced crop yield and quality. To adapt to the dynamic changes in the environment, plants have evolved a series of complex defense mechanisms that are precisely regulated at the molecular, cellular, biochemical, and physiological levels to respond to various stresses. Among them, transcription factors (TFs) are key regulators that control the majority of stress response genes and signal transduction pathways. They are activated by different pathways of signal transduction and can directly or indirectly combine with cis-acting elements to modulate the transcription efficiency of target genes, which play a crucial role in the regulation of plant response to biotic and abiotic stresses.