The seasonal patterns of changes in the content of lipophilic antioxidants β-carotene (β-Car), zeaxanthin (Zx), α-tocopherol (α-Toc), plastoquinone (PQ)/plastoquinol (PQH₂) were studied in the assimilating shoots of evergreen shrub Ephedra monosperma J.G. Gmel ex C.A. Mey under natural conditions of Central Yakutia. The shortening of the photoperiod and the seasonal decrease in temperature induced a 1.4-fold increase in α-Toc content. The fall in the average daily temperature from 0.1 to -8.1°C in October led to a decrease in the content of β-Car as a result of the accumulation of rhodoxanthin (Rhd). In this period a sharp increase in the content of Zx retained overnight was also detected. In winter, elevated content of Zx and α-Toc persisted. During September, the content of PQH₂ increased by 2.5 times and PQ by 1.4 times (compared to July). The beginning of exposure to freezing average daily temperatures from -3 to -5°C led to the depletion of the total PQ pool by 18%. However, the content of PQ_tot in the winter months was 1.5 times higher than at the end of July. The results revealed different timing and temperature ranges of variation for individual antioxidants during the development of frost resistance in ephedra.

Two ginseng species Panax vietnamensis and Panax stipuleanatus are precious medicinal plants restricted in several Vietnam provinces. They are very limited and endangered due to degraded habitats and over-harvesting. To preserve these two species, we used eight nuclear microsatellite markers to investigate genetic variability from the nine populations with 246 individuals for these two ginseng species. Our findings showed a moderate genetic heterozygosity in two species, P. vietnamensis (H_E = 0.386) and P. stipuleanatus (H_E = 0.342). Deficiency of heterozygosity was observed in all the studied populations of P. vietnamensis and three populations of P. stipuleanatus. Some populations had high allelic richness for both species. Private alleles were determined in all the studied populations of P. vietnamensis and two P. stipuleanatus populations. Genetic differentiation was low in two ginseng species. However, habitat loss, over-utilization and over-harvesting can be the main causes of reduced genetic heterozygosity. Neighbor-joining tree and discriminant analysis of principal components detected three major genetic groups. Finally, based on our findings, we propose in situ conservation of populations with high expected heterozygosity, allelic richness, and private alleles. Seed collection should be performed for ex-situ conservation as genetic pools in the future.

The artichoke (Cynara cardunculus subsp. scolymus) is an intriguing source of indigestible sugar polymers such as inulin-type fructans. Artichoke represents an important component of a traditional Mediterranean diet and its edible parts are a good source of many high added value compounds such as inulin, a polymer showing relevant prebiotic properties. Compared to the cultivated varieties, the wild cardoon (C. cardunculus var. sylvestris) growing naturally under harsh conditions and well-adapted to many marginal areas, could have a good potential for use in sustainable production in stressed lands. Here, we evaluated by enzymatic assay, the amount of inulin-type fructans both in artichoke and wild cardoon in the two different organs, heads and rhizomes. The expression pattern of the genes encoding the two key enzymes sucrose:sucrose 1-fructosyltransferase and fructan 1-fructosyltransferase, involved in fructan biosynthesis, have been also evaluated. Our results showed that the amount of inulin-type fructans was higher in the wild cardoon than in the artichoke heads, together with a higher expression of the two key genes involved in the fructan biosynthetic pathway. A conspicuous content of inulin-type fructans was found also in the rhizome, supporting the significant role of these compounds in the storage and in protection from cold and/or winter stresses.

Dendrobium williamsonii and Dendrobium cariniferum (Orchidaceae) are endangered perennial herbs, and they are very similar in morphology. Chloroplast genome sequencing technology provides a powerful tool for molecular analysis to get more infomation for phylogenetic analysis and identification of Dendrobium species. In this study, the complete chloroplast genomes of Dendrobium williamsonii and Dendrobium cariniferum were assembled and characterized using Illumina NovaSeq 6000. The genome sizes are 159 695 and 159 479 bp, including pairs of inverted repeats (27 055 and 27 024 bp) each separated by small single-copy regions (18 451 and 18 488 bp) and large single-copy regions (87 134 and 86 943 bp). The chloroplast genome overall GC content was 37.11% and 37.13%, respectively. Each chloroplast genome encoded the same number (147) of genes, including 88 protein-coding genes, 51 tRNA genes, and 8 rRNA genes. Comparative analysis of chloroplast genomes revealed the high degree of divergence included accD-psaL and ycf4 -cemA. The phylogenetic tree showed the two Dendrobium species formed only one small clade. A pair of primers that could effectively identify the two Dendrobium species were also screened. This study will provide theoretical basis for species identification, genetic breeding, and evolution of Dendrobium.

Bacterial diseases of vegetable crops cause significant losses of yield and substantially decrease food quality. For sustainable development of agriculture, it is highly important to use the most effective strategies for the protection of vegetable crops from bacterial diseases which allows the creation of resistant cultivars and their introduction in regions with an increased risk of damage by phytopathogenic bacteria. This paper reviews the most widespread bacterial diseases of tomatoes, the mechanisms of interaction of plants with phytopathogenic bacteria, and the advantages of the biotechnological strategies over traditional and marker-associated breeding for creation of the resistant tomato cultivars. The current research progress on the use of biotechnological approaches such as cell selection, genetic engineering, genome editing, and gene silencing is summarized, with a special emphasis on the advantages and limitations of these methods.

Low temperature is one of the most severe abiotic stress factors that limit chrysanthemum growth and development. Natural temperature changes are more complex, and cold stress from a laboratory incubator cannot accurately represent the natural temperature stress. Here, nine separate high-throughput mRNA sequencing technology (RNA-Seq) libraries were generated from the RNA sample of roots from different temperatures, including chilling (Ch), freezing (Fr), and control (CK). The 7 069 and 3 952 differentially transcribed genes were identified as CK vs. Ch and CK vs. Fr, respectively. The Kyoto encyclopedia of genes and genomes pathway (KEGG) enrichment analysis showed that significantly different flavonoid biosynthesis and linolenic acid pathways commonly appeared in CK vs. Ch and CK vs. Fr. Arginine and proline metabolism, lipid metabolism, fatty acid degradation, and fructose and mannose metabolism pathways were found in CK vs. Ch, and only in the CK vs. Fr enrichment metabolic pathway included steroid biosynthesis and monoterpenoid biosynthesis. The transcription of genes on differential metabolic pathways and MYBs were successfully validated using quantitative real-time PCR. At the same time, the antioxidant activity, malondialdehyde, and proline content were analyzed under low temperature. These datasets may aid in understanding and carrying out future studies on the molecular basis of cold stress and contribute to chrysanthemum breeding.

Tomato spotted wilt virus (TSWV) has significant economic impact on horticulture worldwide. One of the five proteins encoded by TSWV genome is the multifunctional NSs protein, which is a viral suppressor of RNA silencing (VSR) besides functioning as the effector of Tsw resistance gene in resistant pepper cultivars. In this study we demonstrate the in vivo self-interaction of NSs protein using bimolecular fluorescence complementation and yeast two-hybrid assays, and propose that a highly charged alpha helix located at the second half of the protein is required for self-interaction. Furthermore, we confirmed that self-interaction is not required for its effector function on pepper. Moreover, self-interaction is dispensable for gene silencing suppressor activity, although it enhances the suppression efficiency.

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.

It is common knowledge that R2R3-MYB transcription factors play significant roles in plant biological and physiological processes, especially in the phenylpropanoid metabolism pathway. The cultivated strawberry (Fragaria × ananassa Duch.) is an octoploid (2n = 8x = 56) species from the Rosaceae family and it is also an important fruit crop species. However, the function of R2R3-MYB genes in strawberry remains largely unknown. Here, based on the genome of the cultivated strawberry cv. Reikou, 66 FanMYB genes were found and systematically analyzed. RNA-seq analysis revealed that some FanMYBs exhibited tissue-specific expressions and were methyl jasmonate (MeJA)-responsive. Phylogenetic relationships and protein-protein interaction analysis suggested that 13 FanMYBs were likely associated with phenylpropanoid metabolism. Out of these genes, FanMYB22, FanMYB36, FanMYB47, FanMYB49, and FanMYB63 were post-transcriptionally regulated by miR858 according to the degradome data analysis, suggesting the conservation and complex regulation network in F. × ananassa. Current findings provide a useful resource for future research on the function of FanMYBs and the regulatory mechanism of the phenylpropanoid pathway in strawberry.

Leaves of Lotus japonicus infected by powdery mildew accumulate isoflavonoids, especially vestitol and sativan as protective compounds, whereas their flavonol-glycosides or phenylpropanoic acids content were rather decreased. For a better understanding of the induction of phytoalexin production in L. japonicus, the influence of important signalling molecules, namely methyl jasmonate and salicylic acid, was tested by leaf application, up to 15 d. No effects after spraying the leaves with 0.5 mM salicylic acid were observed regarding the plant isoflavonoid content, whereas methyl jasmonate showed moderate effect on vestitol accumulation. Chitosan application led to a strong increase in vestitol content, sativan and vestitol derivative also increased. In a similar way to the effect of powdery mildew infection, the content of ferulic acid and kaempferol glycosides decreased, except for one compound, identified as kaempferol-6-deoxyhexose, that is the result of acetylation of kaempferol glycosides. The application of chitosan also led to an approximately 2.5- to 3.5-fold increase in hydrogen peroxide content, indicating the involvement of H₂O₂ in the chitosan signalling pathway. The activity of key enzyme of the phenolic biosynthesis, phenylalanine amonia lyase (PAL), was stimulated as well as the expression of 3 PAL-isogenes (LjPAL4, LjPAL6, and LjPAL9), whereas LjPAL8 decreased. Moreover, the expression of two key enzymes of vestitol and sativan biosythesis: pterocarpan reductase and isoflavone synthase were also strongly induced. The data suggest that chitosan acts as an elicitor of the fungal attack in Lotus japonicus that do not lead to a general stimulation of the metabolism of phenols, but rather to a specific induction of isoflavonoid-phytoalexine production, especially for production of vestitol.

Bacterial leaf blight (BLB) is a common disease that affects rice development and yield. The effects of major nutrients, especially nitrogen, on rice BLB susceptibility have been considered when devising rational fertilization strategies. However, the defense mechanism of rice against BLB under phosphate (Pi)-deficient conditions remains uncertain. Jasmonic acid (JA) is a phytohormone produced by rice plants to respond to abiotic and biotic stresses. Here, the involvement of the JA pathway in rice response to Xanthomonas oryzae pv. oryzae (Xoo) under low Pi was investigated in two contrasting rice cultivars G299 and G22. Expressions of JA-related genes under low Pi and Pi-related genes under JA treatment were assessed. The resistant capacity of G299 and G22 against Xoo infection was also investigated. In the JA-sensitive and Pi-sensitive cv. G299, JA-related genes were highly expressed under low Pi, and low Pi-responsive genes were strongly upregulated under JA treatment. Neither JA nor Pi pathways were activated in the JA-tolerant and low Pi-tolerant cv. G22. Low Pi strongly enhanced rice resistance to Xoo in cv. G299. Our study demonstrated that Pi deficiency confers rice resistance to Xoo. The JA pathway modulates the response to low Pi, depending on the cultivar. Pi-response genes are involved in Pi stress and may participate in the regulation of overall plant growth under various abiotic stresses. These findings provide new insights into the interaction between phosphate deficiency and the JA pathway and the subsequent effect on plant disease resistance.

Lycium barbarum Thunb. and Lycium ruthenicum Murray (wolfberries) have been utilized as traditional medicinal and nutritional plants in China for centuries. Much research has been focused on their high quality, yet the molecular mechanisms underlying morphological differences remain unclear. In this study, a comparative analysis of morphological and cytological characteristics indicated that significant differences existed. Meanwhile, transcriptomic analyses of the flower and fruit were performed at different developmental stages, and a total of 54 795 differentially expressed genes (DEGs) were screened. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses showed that these DEGs were significantly enriched in substance metabolism, catalytic activity, single organism process, starch and sucrose metabolism, carotenoid biosynthesis, amino sugar and nucleotide sugar metabolism, phenylpropanoid biosynthesis, and other pathways. Based on these significantly enriched pathways, the ratio between nonsynonymous and synonymous substitution rates (Ka/Ks), and numerous studies related to flower and fruit development, we preliminarily screened eight transcription factor families related to flower and fruit development and counted the number of potential transcription factor genes. These candidate genes could provide a basis for future functional verification, helping to further research on the molecular mechanism of morphological differences in the two Lycium species.

Thioredoxins (Trx) are small multifunctional redox proteins that contain thioredoxin conserved domain and active site WCXXC. The Trx family has an important role in multiple processes, including electron transport, seed germination, redox regulation, biotic and abiotic stresses resistance, etc. Although Trx genes have been extensively characterized in some plants, they have not been reported in peanut until now. The identification of AhTrx genes provides potential candidate genes for studying their effects and regulatory mechanisms in peanut (Arachis hypogaea L.) growth and development, especially under aluminium (Al) stress. It is also helpful to further analyze the Al resistance pathway in plants. Seventy AhTrx genes were identified using a genome-wide search method and conservative domain analysis. Then the basic physicochemical properties, phylogenetic relationship, gene structure, chromosomal localization, and promoter prediction were studied by the bioinformatic methods. Furthermore, the expressions of AhTrx genes under different Al treatment times in two peanut cultivars were tested using a real-time quantitative polymerase chain reaction. Seventy AhTrx genes were identified and characterized. Phylogenetic tree analysis showed that all AhTrx members could be classified into 9 groups with different conserved domains. Motif 1 was found to exist in every sequence, with an active site. Furthermore, the gene structures showed that the AhTrx family was complicated and changeable during evolution. The chromosomal localization indicated that the distribution and density of the Trx family on 20 peanut chromosomes were uneven. Predictive promoter analysis indicated that AhTrx proteins might play a role in phytohormones synthesis and stress response. Finally, the expression patterns of the AhTrx genes showed that every gene was differently expressed under Al treatment in different peanut cultivars, some were obvious, others had no significant difference, some were at a high level, while others were at a low level. This study systematically identifies the Trx gene family in peanut, providing some candidates for further study on its effects and regulatory mechanism under Al stress in peanut.

The family of pyrabactin resistance 1 (PYR1)/PYR1-like (PYL) regulatory components of ABA receptors (RCAR) play a vital role in the initial step of ABA signaling. To understand the expression mode of PYL genes in response to various abiotic stresses in Chinese cabbage (Brassica rapa ssp. pekinensis), the members of BrPYL gene family were first identified with the relevant bioinformatics software. And then, the relative expressions of identified BrPYLs after heat, cold, drought, and salt treatments for 0, 24, 48, and 72 h were determined via real-time quantitative PCR. Here, we identified 24 PYLs in the B. rapa genome. Based on the phylogenetic analysis, these BrPYL genes were divided into three classes and distributed on ten chromosomes in Chinese cabbage. Most of BrPYL genes in the same group have similar gene structures and intron numbers. There were seven genes (BrPYL5, BrPYL8, BrPYL22, BrPYL3, BrPYL18, BrPYL11, and BrPYL21) from Group A with two introns and one gene (BrPYL19) from Group D with one intron. Analysis of conserved motifs suggested that every group contained motif 2 containing the Polyketide_cyc2 domain. Subsequently, the prediction of cis-acting elements indicated that BrPYL genes had 5 stress-related elements and 5 hormone-related elements, among which the number of MYC (dehydration reaction) was the highest, suggesting that BrPYL genes could respond to hormones and abiotic stresses. Expression patterns under four abiotic stresses showed that the expressions of BrPYL4, BrPYL11, BrPYL21, and BrPYL23 responded to these stresses at different time points. To conclude, we identified the BrPYL genes and build the BrPYLs expression mode in response to various abiotic stresses. This study provides a theoretical basis for stress-resistance breeding of Chinese cabbage.

To reveal the regulation mechanism of terpenoid biosynthesis in the leaves of Eucalyptus camaldulensis, the content of volatiles in eucalyptus leaves and the transcriptome databases of young and mature leaves were analyzed. The results showed that E. camaldulensis contains 92 and 89 kinds of volatile substances in the young and mature leaves, respectively. Among them, the content of 1,8-cineole, β-pinene, and other substances was significantly different in young and mature leaves. A total of 99 802 unigenes were obtained from the transcriptome database of young and mature leaves of E. camaldulensis and 18 441 genes displayed obviously differential expressions during both developmental stages. There were 6 982 up-regulated unigenes and 11 461 down-regulated unigenes in the young leaf stage compared to the mature leaf stage. The key genes for terpenoid biosynthesis, including limonene synthase-10, limonene synthase-11, myrcene synthase-1, α- pinene synthase-2, and 1,8-cineole synthase-2, were selected for further analysis to explore the mechanism of gene regulation and genetic transformation. The expressions of key genes were validated by RT-qPCR, and their expressions were consistent with RNA-seq data. WRKY, MYB, NAC, and bHLH transcription factors (TFs) displayed important regulatory effects on the above key genes. Thus, a regulatory network model of terpenoid biosynthesis was constructed using target genes and TFs during leaf development in E. camaldulensis. These results provide theoretical evidence for understanding the terpenoid biosynthesis in plants and reference for terpenoids utilization by genetic engineering methods in E. camaldulensis.

Midvein is an important structure of the upright leaf of rice, and its normal development is essential to the formation of a common plant type of rice (Oryza sativa L.). To reveal the effect of midvein deficiency on photosynthesis-related characteristics, leaf microstructure, and vein characteristics, the photosynthetic features between the midvein-deficient mutant dl-14 and wild-type Huanghuazhan plants were analyzed. The results indicated that the midvein area of the dl-4 mutant lacked large intercellular space and instead it was filled with mesophyll cells. Moreover, the vein density of the dl-14 mutant was significantly higher than that in cv. Huanghuazhan. Chlorophyll (Chl) a, Chl b, and carotenoid content were markedly elevated in dl-14. In terms of photosynthetic characteristics, we observed that under high irradiance and high CO₂ concentration, the net photosynthetic rate of dl-14 plants was significantly higher than that of Huanghuazhan plants, but its water use efficiency was significantly lower. In addition, several major photosynthetic parameters, including characteristics of chlorophyll fluorescence (the efficiency of excitation capture of open PS II center, photochemical quenching, effective quantum yield of PS II photochemistry, and electron transfer rate) were significantly higher in dl-14 plants compared to Huanghuazhan plants, but the nonphotochemical quenching of dl-14 mutant was significantly lower than that of Huanghuazhan. These findings indicate that the dl-14 mutant has higher vein density, stronger photon conversion ability, and weaker radiation dissipation ability. This study can provide theoretical support for breeders to use the midvein-deficient mutant.

Tomato yellow leaf curl virus (TYLCV), a whitefly-transmitted single-stranded DNA (ssDNA) virus, causes the most important viral disease of tomato worldwide. TYLCV-mediated disease is mainly controlled via extensive insecticide sprays aiming at the whitefly vector. RNA-based vaccination was proven to be a non-transgenic approach leading to efficient plant virus control. In this work, double-stranded RNA (dsRNA) molecules deriving from sequences of the C4 and V2 genes of TYLCV-Mild were produced in vitro and topically applied onto tomato plants along with the virus (via agroinfiltration). DsC4 and dsV2 application reduced disease incidence to 23 and 46 %, respectively, while TYLCV positive control reached 64 %. Bioinformatics analysis of the virus-specific small interfering RNAs (vsiRNAs) from TYLCV-infected tomato revealed 'hot' and 'cold' spots in the TYLCV-Mild genome. Interestingly, the viral C-strand had twofold siRNA reads when compared to that of the V-strand. Overall, vsiRNAs of negative and positive polarity were almost equal (53.5 vs. 46.6 %); vsiRNAs of negative polarity prevailed at the V-strand. Stem-loop RT-PCR validated the presence of six vsiRNAs (hot or cold spots) in TYLCV-Mild-infected and dsRNA-treated tomato. The exogenously applied dsRNA was found to rapidly move systemically in tomato and was detected for 54 days post treatment (dpt). The applied dsRNA molecules were successfully processed by the Dicer-like proteins (DCLs) in tomato since small interfering RNAs (siRNAs) deriving from the dsRNA were detected for at least 54 dpt. This consists the first report of dsRNA-based vaccination applied against a monopartite geminivirus.

Paspalum fasciculatum Willd. ex Flüggé grows in mining soils which are Cd- and Pb-contaminated where it exhibits tolerance to Pb and the ability to extract Pb from these soils. To elucidate tolerance mechanisms to Pb-stress, liquid chromatography with tandem mass spectrometry (LC-MS/MS) was used to quantify changes in the accumulation of proteins in leaves. We identified 323 proteins involved in primary metabolism and response to biotic or abiotic stresses. Although proteins involved in the processes of photosynthesis and saccharide and energy metabolism presented the greatest amount of down-regulated proteins, the plant was able to maintain photosynthetic functions and obtain energy to sustain the vital balance. P. fasciculatum based their tolerance on increased antioxidant defenses, improving the protection and repair of proteins and transduction signals to coordinate physiological response to Pb-stress. Our results provide important information to understand the tolerance mechanisms in P. fasciculatum and could be important in future molecular studies on the resistance and accumulation of Pb in plants.

Trehalose is a nonreducing disaccharide that is involved in the regulation of plant responses to a variety of environmental stresses. Trehalose 6-phosphate synthase (TPS) and trehalose 6-phosphate phosphatase (TPP) are two key enzymes in trehalose synthesis and they are widely distributed in higher plants. At present, TPS family genes have been systematically identified and analyzed in many plant species, but the TPP family genes have been rarely studied. In this study, ten TPS and six TPP genes in cannabis (Cannabis sativa L.) were identified at the genomic level. The phylogenetic tree of TPS and TPP family members in cannabis, Arabidopsis, and rice was constructed, and all the genes were divided into three subgroups: Class I, Class II, and Class III. The number of exons and motif types among Class I members was exactly the same, as were Class II members, but the gene structure and motif types of Class III members were slightly different. There were four pairs of CsTPSs and CsTPPs that had gene duplication, indicating that gene duplication events played an important role in the amplification of TPS and TPP families in cannabis. The results of expression analysis under abiotic stresses showed that 68.75 % of CsTPS and CsTPP genes were significantly induced by at least one abiotic stress. Among these genes, the expression of CsTPS1, CsTPS9, and CsTPPA was highest under at least one abiotic stress. These three genes may play a key role in abiotic stress responses. Most of the CsTPS and CsTPP genes that are closely located in the evolutionary tree have the same or similar functions. To our knowledge, this is the first paper that systematically reports the TPS and TPP gene families in cannabis.

Drought and salinity, which can alter the water balance, disrupt the ionic equilibrium, and create reactive oxygen species (ROS), are capable of destroying plant tissues. In this study, transcriptomics, proteomics, and metabolomics have been used to elucidate various abiotic stress responses. In transcriptional signaling pathways, abscisic acid (ABA) is one of the plant phytohormones that regulate the stress response. On the other hand, several regulons and factors of transcription contributed in the reaction to osmotic stresses, as well as in ABA-dependent/independent signaling pathways. However, the findings display that intricate molecular reaction of plants under stress conditions may be controlled by complicated regulative networks of gene expression and signal transduction, as well as by the interaction between them. From the point of view of proteomics, protein modifications in response to stress can be considered as a molecular tool to improve the resistance of plants to environmental stresses. These studies have provided new information about the significance of several gene and protein networks involved in the response of plants to salinity and drought, and the induction of tolerance. Moreover, identifying the crucial pathways which are involved in salinity and drought resistance can open doors for the establishment of commercial-resistant crop cultivars, and might be very useful in the next-generation crop breeding strategies to produce plants with salinity and drought-resistant traits.

Late embryogenesis abundant (LEA) proteins are important for promoting the growth and stress tolerance of plants. They are widely involved in plant growth regulation and responses to hormones and environmental factors. However, knowledge of the functions of the LEA gene in ginseng species remains limited. In this study, a Panax ginseng LEA gene (PgLEA) expression vector was constructed, and stable transgenic Arabidopsis lines were established. The PgLEA protein was classified in the LEA-2 subgroup. Reverse-transcription quantitative PCR analysis showed that the expression of PgLEA increased under 300 mM NaCl or 10 % (m/v) polyethylene glycol treatments. Under salt and osmotic stresses, overexpression of PgLEA in transgenic Arabidopsis plants improved germination rate, root length, and survival rate compared to wild-type plants. In response to drought or salt stress, transgenic plants increased proline accumulation, decreased malonaldehyde content and ion leakage. Furthermore, the transgenic plants exhibited significantly increased activity of superoxide dismutase, peroxidase, and catalase, and reduced accumulation of hydrogen peroxide and superoxide. Moreover, overexpression of PgLEA affected the expression of genes related to salt/drought stress. Taken together, PgLEA is a positive regulator of drought and salinity stress, and positively functioned in pleiotropic effects through regulating osmotic balance, reactive oxygen species scavenging and inducing transcription of stress-related genes. PgLEA may enable ginseng plants to adapt to adverse environments. The data presented herein imply that PgLEA may be useful for breeding new stress-tolerant ginseng cultivars.

Long-term low temperatures restrict the regrowth of winter wheat (Triticum aestivum L.), thus decreasing agricultural output. Non-enzymatic expansins, which are related to plant growth, have been reported to respond to drought, salinity, and low-temperature stress. We obtained an expansin 3 gene, TaEXPA9. It is located in winter wheat cv. Dongnong with high cold hardiness. We analyzed the expression patterns of TaEXPA9-A/B/D in this cultivar and conducted a subcellular localization analysis of TaEXPA9-A/B/D in the onion epidermis. Transgenic Arabidopsis thaliana line with EXPA9-A/B/D overexpression was obtained to examine the effects of the orthologous genes of these expansins on plant growth and low-temperature stress resistance. The results showed that EXPA9-A/B/D expression significantly increased at 4 °C, it was higher in the roots than in shoots, and EXPA9-A/B/D was localized in the cell wall. The roots were well-developed in the transgenic A. thaliana, and the growth-related markers and setting rate were better than in the wild-type. Recovery was stronger in the transgenic plants after freezing stress. At low-temperature stress, the antioxidant enzyme activities and content of osmoregulatory substances in the TaEXPA9-A/B/D-overexpressing A. thaliana plants were significantly higher than in the wild-type plants, and the degree of membrane lipid peroxidation was lower. In summary, TaEXPA9 orthologous genes participate in the low-temperature stress response, and they might be of great importance in molecular breeding.

The myeloblastosis (MYB) transcription factors are essential for plant stress responses. They can enhance plant tolerance to abiotic stresses (e.g., drought, salinity, and cold) via improved physiological and biochemical responses including the accumulation of metabolites. In this study, we constructed a Panax ginseng MYB4 (PgMYB4) gene expression vector and established the stable transgenic Arabidopsis thaliana lines to study the effects of this gene on plant stress tolerance. The germination rate and seedling taproot length were greater for the PgMYB4-overexpressing plants than for the wild-type plants. Accordingly, the overexpression of PgMYB4 in Arabidopsis enhanced seedling tolerance to drought, salt, and cold conditions. Under drought stress, the relative chlorophyll content decreased less, the proline content increased more, and the water loss rate decreased more in the transgenic plants than in the wild type. The expressions of stress-related genes responsive to dehydration 19A, responsive to dehydration 22, responsive to desiccation 29A, cold-regulated 15A, cold-regulated 47, and pyrroline-5-carboxylate synthase 1 were significantly upregulated in the transgenic Arabidopsis plants. Under high salt stress, the kinesin 1 (KIN1) expression was significantly upregulated in the transgenic plants. In response to the low temperature stress, the dehydration-responsive element binding protein 2A and KIN1 expressions increased dramatically in the transgenic Arabidopsis plants. Thus, PgMYB4 positively regulated the stress tolerance gene networks, which promoted the expression of anti-stress effector genes. This gene may be useful for ginseng breeding programs aiming to develop new cultivars with enhanced stress tolerance.

Atractylodes lancea (Thunb.) DC has been used widely as a medicinal herb for centuries and is now being used to treat COVID-19 pneumonia. Terpenoids are thought to be its main pharmacologically active constituents. However, their biosynthesis remains uncharacterized in this species. In this study, the terpene synthase gene AlTPS1 was cloned and functionally characterized. We found that AlTPS1 was a bifunctional enzyme that catalyzed the conversion of farnesyl diphosphate to nerolidol and geranyl diphosphate to linalool in vitro. However, it functioned only in the nerolidol production in vivo by transient expression of the AlTPS1 gene in Nicotiana benthamiana leaves maybe due to subcellular compartmentalization of the AlTPS1 in the cytosol. Furthermore, AlTPS1 was highly expressed in leaves, considered to be the sites of nerolidol synthesis. This study is the first in which the cloning and expression of the AlTPS1 gene from A. lancea were analyzed, and it has provided new insights into terpene biosynthesis in A. lancea.

According to the survey, wild purslane (Portulaca oleracea L.) has two different ecotypes, one with the red stem living in an arid environment and one with the green stem living in a humid environment. In order to explore the physiological response strategies of plants to environmental changes, these two ecotypes of purslane were selected as experimental materials. Physiological indices were determined and transcriptome analysis was carried out to screen the differentially expressed genes (DEGs) from two ecotypes of purslane. The results showed that the content of soluble sugars, proline, anthocyanins, and chlorophylls was significantly different, and most DEGs belonged to the WRKY and NAC families. Finally, the results of transcriptome analysis were verified by real-time qPCR. Therefore, it can be inferred that the transcription factor (TF) families may play an important role in physiological response strategies by regulating the changes of anthocyanins and osmotic regulators (soluble sugars, proline, etc.) through the abscisic acid signalling pathway. This will accelerate the study of purslane at the molecular level, provide corresponding theoretical support for its artificial domestication, and drought breeding.

Agarwood, the resin part of Aquilaria spp., is valued in medicine, perfumes, and incense. The most important components of agarwood are sesquiterpenes, which are produced only when a healthy tree is wounded. Agarwood sesquiterpene synthase 1 (ASS1) is one of key enzymes responsible for the biosynthesis of sesquiterpenes in Aquilaria sinensis (Lour.) Gilg, and it is a typical wound-inducible synthase. To elucidate its regulatory mechanism at the transcriptional level, a 978-bp sequence upstream of the translation initiation codon ATG of the promoter for ASS1 was cloned. Computational analysis revealed that this promoter contained many known cis-elements including several defense related transcriptional factor-binding boxes. To functionally validate the promoter, a 5' truncated fragment fused with the β-glucuronidase (GUS) reporter gene was used for generating stable transgenic Arabidopsis plants. The spatial and temporal expression patterns of GUS in transgenic Arabidopsis showed that the promoter of ASS1 was induced by mechanical wound and mainly expressed in vascular bundles. Subcellular localization showed that ASS1 localized in the nucleus and plasma membrane. Here, identification of the ASS1 promoter not only lays a foundation for studying its transcriptional regulation, but also provides clues for studying the synthesis mechanism of agarwood sesquiterpenes.

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.

The trihelix genes encode plant-specific transcription factors, which play a vital role in plant morphological and developmental processes. However, information about the presence of trihelix genes in sunflower (Helianthus annuus L.) is scarce. Sunflower belongs to composite family and possesses strong drought and salt-alkali tolerance. In this study based on H. annuus genome data, we have identified and analyzed the trihelix genes with a complete description of their physical and chemical properties, phylogenetic relationships, motif composition, chromosome distribution, exon-intron structure, cis-acting elements, and chromosome collinearity. In H. annuus, 31 full-length trihelix genes were identified and categorized into six subgroups (SIP, GT1, SH4, Gδ, GT-γ, and GT2). Multiple Em for motif elicitation (MEME), used for conservative motif analysis, identified 10 distinct motifs unevenly distributed on 31 trihelix genes. In addition to that, chromosome localization analysis showed the number and distribution of these trihelix genes on 17 chromosomes of H. annuus. Transcriptional structure analysis revealed the structure of introns and exons of different gene members. Furthermore, cis-element analysis identified 19 different types of cis-elements mainly related to abiotic stress, hormones, and growth and development of plant. Results of this study manifested novel insights into phylogenetic relationships and possible functions of H. annuus trihelix genes. Moreover, these findings can assist in future studies regarding specific physiological effects of H. annuus trihelix transcription factors.

Nucleotides are the basic elements of the genetic material, participate in bio-energetic processes, are cofactors and components of secondary metabolites, etc. Nucleotide hydrolases (nucleotidases) are phosphatases that remove the 5'-phosphate group from the nucleotides and play a crucial role in nucleotide metabolism. In this study, genes encoding putative nucleotidases in Phaseolus vulgaris have been identified, and the effect of methyl jasmonate (MeJA) on both nucleotidase activity and gene expression has been addressed. The predicted nucleotidase peptides include the conserved domains characteristic of the haloacid dehalogenase-like hydrolase superfamily. The analysis of the expression of the 11 identified genes in radicles of common bean seedlings elicited with MeJA showed that 3 of them are highly induced by this phytohormone in a dose-dependent manner. Nucleotidase activity in radicles from MeJA treated plants was higher than in not elicited seedlings, and this induction was observed with all the nucleotides assayed (mono-, di- or triphosphate) and with purine or pyrimidine nucleotides. MeJA is involved in biotic and abiotic stress, and the induction of nucleotide metabolism in response to this treatment suggests a relevant role for nucleotides in the seedlings response to unfavourable conditions.