Identification of a 301 bp promoter core region of the SrUGT91D2 gene from Stevia rebaudiana that contributes to hormone and abiotic stress inducibility.

BACKGROUND: The UDP-glucuronosyltransferase 91D2 (SrUGT91D2) gene is a crucial element in the biosynthetic pathway of steviol glycosides (SGs) and is responsible for creating 1,2-ß-D glucosidic bonds at the C19 and C13 positions. This process plays a vital role in the synthesis of rebaudioside M (RM) and rebaudioside D (RD). The promoter, which regulates gene expression, requires functional analysis to understand gene expression regulation. However, investigations into the function of the promoter of SrUGT91D2 (pSrUGT91D2) have not been reported. RESULTS: The pSrUGT91D2 was isolated from six S. rebaudiana lines, and subsequent multiple sequence comparisons revealed the presence of a 26 bp inDel fragment (pSrUGT91D2-B1188 type) in lines GP, GX, 110, 1114, and B1188 but not in the pSrUGT91D2 of line 023 (pSrUGT91D2-023 type). Bioinformatics analysis revealed a prevalence of significant cis-regulatory elements (CREs) within the promoter sequences, including those responsive to abscisic acid, light, anaerobic conditions, auxin, drought, low temperature, and MeJA. To verify the activity of pSrUGT91D2, the full-length promoter and a series of 5' deletion fragments (P1-P7) and a 3' deletion fragment (P8) from various lines were fused with the reporter ß-glucuronidase (GUS) gene to construct the plant expression vector, pCAMBIA1300-pro∷GUS. The transcriptional activity of these genes was examined in tobacco leaves through transient transformation. GUS tissue staining analysis and enzyme activity assays demonstrated that both the full-length promoter and truncated pSrUGT91D2 were capable of initiating GUS expression in tobacco leaves. Interestingly, P8-pSrUGT91D2-B1188 (containing the inDel segment, 301 bp) exhibited enhanced activity in driving GUS gene expression. Transient expression studies of P8-pSrUGT91D2-B1188 and P8-pSrUGT91D2-023 in response to exogenous hormones (abscisic acid and indole-3-acetic acid) and light indicated the necessity of the inDel region for P8 to exhibit transcriptional activity, as it displayed strong responsiveness to abscisic acid (ABA), indole-3-acetic acid (IAA), and light induction. CONCLUSIONS: These findings contribute to a deeper understanding of the regulatory mechanism of the upstream region of the SrUGT91D2 gene and provide a theoretical basis for future studies on the interaction between CREs of pSrUGT91D2 and related transcription factors.

Methyl jasmonate effects on Lactuca serriola L.: Antioxidant defense and bioactive compound changes.

The effect of methyl jasmonate (MeJA) foliar spray on the activity of antioxidant enzymes-Superoxide dismutase (SOD), Catalase (CAT), Ascorbate peroxidase (APX), and Guaiacol peroxidase (GPX)-along with assessments of total phenolic and flavonoid contents and antioxidant activity (IC50), was examined in Prickly lettuce (Lactuca serriola L.). The study involved treating plants with three MeJA solutions (0, 200, and 400 µM) and harvesting samples at four distinct time intervals. Varied MeJA concentrations and time intervals resulted in a substantial increase in the activity of all the antioxidant enzymes investigated in this study. Both concentration levels and time courses exhibited progressive outcomes. Moreover, MeJA treatment led to elevated levels of total phenolic and flavonoid contents, reaching peaks of 17.02 (mg GAL/g DW) and 8.3 (mg QUE/g DW), respectively, particularly in response to the 400 µM concentration. However, the total flavonoid content did not show any significant variation between the two concentrations. Based on the half-maximal inhibitory concentration (IC50) values, the antioxidant activity in MeJA-treated plants was found to be lower compared to the controls. However, our findings suggest that, under specific conditions discussed in this study, MeJA has the potential to enhance the nutritional value of L. serriola.

Unveiling the potential role of gibberellic acid, melatonin and indole acetic acid on parthenocarpy, physiological traits and phytochemical responses in Hibiscus sabdariffa L.

The economic part of the Hibiscus sabdariffa L. (Malvaceae) plant is the sepal. One of the main challenges in harvesting this product is separating its seeds, which are surrounded by sepals. If the parthenocarpy process occurs without seeds, the labor costs are reduced and the profits from the production of this plant are increased. In current study, the effect of gibberellic acid (GA3), melatonin (M), and indole acetic acid (IAA) on the induction of parthenocarpy in H. sabdariffa plants was investigated. The study was conducted as a factorial experiment in the form of randomized complete block design with three replications. Different concentrations of GA3 (0 (control), 700, 800, and 900 ppm), M (0 (control), 100, 200, and 400 ppm), and IAA (0 (control), 1000, 1200, and 1400 ppm) were foliar sprayed after the emergence of the flower bud on the 50th, 60th, and 70th days of planting, and the control plants were also sprayed with distilled water. Various measurements were taken including the number of seeds per boll, parthenocarpy percentage, capsule volume, number of bolls per plant, number of mature seeds, and phytochemical parameters such as anthocyanin, chlorophyll and carotenoid content, antioxidant value, total phenol and flavonoid content, and soluble solids. The application of GA3 at 800 and 900 ppm along with IAA at 1000 ppm and M at 100 and 200 ppm led to the production of parthenocarpy fruits and showed the best results in the induction of parthenocarpy. The control group indicated the highest number of mature seeds per boll. The highest amount of phenol and flavonoid contents were obtained in plants treated with GA3 at 800 ppm. For anthocyanin, the control group showed the highest value (1.63 mg g-1), and in the case of the antioxidant trait, plants exposed to 100 ppm M showed the highest IC50 (40.68%). Hence, the application of plant growth regulators with appropriate concentrations can be effective in inducing parthenocarpy in H. sabdariffa plants. Additionally, parthenocarpy-induced by GA3, IAA, and M had different impacts on fruit quality and quantity, suggesting that the effect depends on the type of employed hormones used and their concentrations.

Optimizing oilseed rape growth: Exploring the effect of foliar biostimulants on the interplay among metabolism, phenology, and yield.

The current agricultural system is in search of new strategies to achieve a more sustainable production while keeping or even increasing crop yield and quality. In this scenario, the application of biostimulants constitutes a potent solution. In the current study, the impact of a blue-green microalgal extract (MB) and a pig tissue hydrolysate (PTH) on rapeseed plants' development was characterized. Obtained results revealed a positive effect on yield parameters of plants treated with MB and, especially, PTH; this was associated to an improvement on the photosynthetic performance. Moreover, this study remarked the effects of biostimulants on plant phenology through their pivotal role in modulating developmental processes. More specifically, proteomic, metabolomic, and hormone content analyses revealed distinct alterations associated with the acceleration of phenology induced by biostimulant application. Additionally, some antioxidant enzymes and stress-related compounds were up-regulated upon MB and PTH treatments, indicating enhanced plant defense mechanisms in response to accelerated phenological transitions. Such findings highlight the intricate interplay between biostimulants and plant physiology, wherein biostimulants orchestrate rapid developmental changes, ultimately influencing growth dynamics. Altogether, the current study reveals that the application of both MB and PTH biostimulants promoted rapeseed plant phenology and productivity associated with an improvement in the photosynthetic machinery while boosting other physiological and molecular mechanisms.

Characterization and expression analysis of the MADS-box gene AGL8 in cotton: insights into gene function differentiation in plant growth and stress resistance.

BACKGROUND: AGAMOUS-LIKE 8 (AGL8) belongs to the MADS-box family, which plays important roles in transcriptional regulation, sequence-specific DNA binding and other biological processes and molecular functions. The genome of cotton, a representative polyploid plant, contains multiple AGL8 genes. However, their functional differentiation is still unclear. METHODS AND RESULTS: In this study, a comprehensive genomic analysis of AGL8 genes was conducted. Cotton AGL8s were subdivided into four subgroups (Groups 1, 2, 3, and 4) based on phylogenetic analysis, and different subgroups of AGL8s presented different characteristics, including different structures and conserved motifs. With respect to the promoter regions of the GhAGL8 genes, we successfully predicted cis-elements that respond to phytohormone signal transduction and the stress response of plants. Transcriptome data and real-time quantitative PCR validation indicated that three genes, namely, GH_D07G0744, GH_A03G0856 and GH_A07G0749, were highly induced by methyl jasmonate (MeJA), salicylic acid (SA), and abscisic acid (ABA), which indicated that they function in plant resistance to abiotic and biotic stresses. CONCLUSIONS: The information from the gene structure, number and types of conserved domains, tissue-specific expression levels, and expression patterns under different treatments highlights the differences in sequence and function of the cotton AGL8 genes. Different AGL8s play roles in vegetative growth, reproductive development, and plant stress resistance. These results lay a foundation for further study of GhAGL8s in cotton.

Alteration in certain growth, biochemical, and anatomical indices of grapevine (Vitis vinifera) in response to the foliar application of auxin under water deficit.

Drought-induced stress represents one of the most economically detrimental natural phenomena impacting grapevine (Vitis vinifera ) development, yield, and fruit characteristics. Also, auxin is one of the most important plant growth regulators that can reduce damage caused by stress in plants. In this study, the impact of exogenously sprayed auxin (0, 50, and 200mgL-1 ) on growth, biochemical, and anatomical parameters was investigated in two grapevine varieties (cvs. 'Rashe' and 'Fakhri') under water deficit. According to our findings, water deficit led to a notable decrease in growth, protein content, and anatomical parameters; but significantly enhanced electrolyte leakage. Grapevines exposed to water deficit exhibited substantial increases in total phenolic compounds and antioxidant activity. Applying 50mgL-1 napthalene acetic acid (NAA) reduced the effects of water deficit in both grapevine cultivars by decreasing electrolyte leakage (15% in 'Rashe' and 20% in 'Fakhri'), and accumulating protein content (22% 'Rashe' and 32% 'Fakhri'), total phenolic compounds (33%'Rashe' and 40% 'Fakhri'), and antioxidant capacity (11% 'Rashe' and 39% 'Fakhri'); anantomical parameters were also improved. However, application of 200mgL-1 NAA had adverse effects on growth and biochemical traits of grapevines, with a more pronounced impact on root growth and anatomical parameters compared to other NAA concentrations. In conclusion, the application of 50mgL-1 NAA enhanced grapevine growth, enabling them to better thrive under water deficit.

Genome-wide identification, characterization and expression pattern analysis of TIFY family members in Artemisia argyi.

BACKGROUND: Plant-specific TIFY proteins play crucial roles in regulating plant growth, development, and various stress responses. However, there is no information available about this family in Artemisia argyi, a well-known traditional medicinal plant with great economic value. RESULTS: A total of 34 AaTIFY genes were identified, including 4 TIFY, 22 JAZ, 5 PPD, and 3 ZML genes. Structural, motif scanning, and phylogenetic relationships analysis of these genes revealed that members within the same group or subgroup exhibit similar exon-intron structures and conserved motif compositions. The TIFY genes were unevenly distributed across the 15 chromosomes. Tandem duplication events and segmental duplication events have been identified in the TIFY family in A. argyi. These events have played a crucial role in the gene multiplication and compression of different subfamilies within the TIFY family. Promoter analysis revealed that most AaTIFY genes contain multiple cis-elements associated with stress response, phytohormone signal transduction, and plant growth and development. Expression analysis of roots and leaves using RNA-seq data revealed that certain AaTIFY genes showed tissue-specific expression patterns, and some AaTIFY genes, such as AaTIFY19/29, were found to be involved in regulating salt and saline-alkali stresses. In addition, RT-qPCR analysis showed that TIFY genes, especially AaTIFY19/23/27/29, respond to a variety of hormonal treatments, such as MeJA, ABA, SA, and IAA. This suggested that TIFY genes in A. argyi regulate plant growth and respond to different stresses by following different hormone signaling pathways. CONCLUSION: Taken together, our study conducted a comprehensive identification and analysis of the TIFY gene family in A. argyi. These findings suggested that TIFY might play an important role in plant development and stress responses, which laid a valuable foundation for further understanding the function of TIFY genes in multiple stress responses and phytohormone crosstalk in A. argyi.

A new Bowman-Birk type protease inhibitor regulated by MeJA pathway in maize exhibits anti-feedant activity against the Ostrinia furnacalis.

Jasmonic acid (JA), an important plant hormone, plays a crucial role in defending against herbivorous insects. In this study, we have identified a new Bowman-Birk type protease inhibitor (BBTI) protein in maize that is regulated by the JA pathway and exhibits significant antifeedant activity, which is notably induced by exogenous Methyl Jasmonate and Ostrinia furnacalis feeding treatments. Bioinformatics analysis revealed significant differences in the BBTI protein among different maize inbred lines, except for the conserved domain. Prokaryotic and eukaryotic expression systems were constructed and expressed, and combined with bioassays, it was demonstrated that the antifeedant activity of BBTI is determined by protein modifications and conserved domains. Through RT-qPCR detection of BBTI and JA regulatory pathway-related genes' temporal expression in different maize inbred lines, we identified the regulatory mechanism of BBTI synthesis under the JA pathway. This study successfully cloned and identified the MeJA-induced anti-feedant activity gene BBTI and conducted functional validation in different maize inbred lines, providing valuable insights into the response mechanism of insect resistance induced by the plant JA pathway. The increased expression of the anti-feedant activity gene BBTI through exogenous MeJA induction may offer a potential new strategy for mediating plant defense against Lepidoptan insects.

Diethyl aminoethyl hexanoate ameliorates salt tolerance associated with ion transport, osmotic adjustment, and metabolite reprograming in white clover.

BACKGROUND: Soil salinization is a serious environmental hazard, limiting plant growth and production in different agro-ecological zones worldwide. Diethyl aminoethyl hexanoate (DA-6) as an essential plant growth regulator (PGR) exhibits a beneficial role in improving crop growth and stress tolerance. However, the DA-6-regulated effect and mechanism of salt tolerance in plants are still not fully understood. The objective of current study was to disclose salt tolerance induced by DA-6 in relation to changes in water and redox balance, photosynthetic function, ionic homeostasis, and organic metabolites reprogramming in white clover (Trifolium repens). RESULTS: A prolonged duration of salt stress caused water loss, impaired photosynthetic function, and oxidative injury to plants. However, foliar application of DA-6 significantly improved osmotic adjustment (OA), photochemical efficiency, and cell membrane stability under salt stress. In addition, high salinity induced massive accumulation of sodium (Na), but decreased accumulation of potassium (K) in leaves and roots of all plants. DA-6-treated plants demonstrated significantly higher transcript levels of genes involved in uptake and transport of Na and K such as VP1, HKT8, SOS1, NHX2, NHX6, and SKOR in leaves as well as VP1, HKT1, HKT8, H+-ATPase, TPK5, SOS1, NHX2, and SKOR in roots. Metabolomics analysis further illustrated that DA-6 primarily induced the accumulation of glucuronic acid, hexanoic acid, linolenic acid, arachidonic acid, inosose, erythrulose, galactopyranose, talopyranose, urea, 1-monopalmitin, glycerol monostearate, campesterol, stigmasterol, and alanine. CONCLUSIONS: The DA-6 significantly up-regulated transcript levels of multiple genes associated with increased Na+ compartmentalization in vacuoles and Na+ sequestration in roots to reduce Na+ transport to photosynthetic organs, thereby maintaining Na+ homeostasis under salt stress. The accumulation of many organic metabolites induced by the DA-6 could be attributed to enhanced cell wall and membrane structural stability and functionality, OA, antioxidant defense, and downstream signal transduction in leaves under salt stress. The present study provides a deep insight about the synergistic role of DA-6 in salt tolerance of white clover.

Exogenous melatonin promoted seed hypocotyl germination of Paeonia ostia 'Fengdan' characterized by regulating hormones and starches.

Background: Seed hypocotyl germination signifies the initiation of the life cycle for plants and represents a critical stage that heavily influences subsequent plant growth and development. While previous studies have established the melatonin (MEL; N-acetyl-5-methoxytrytamine) effect to stimulate seed germination of some plants, its specific role in peony germination and underlying physiological mechanism have yet to be determined. This study aims to evaluate the MEL effect for the hypocotyl germination of peony seeds, further ascertain its physiological regulation factors. Methods: In this work, seeds of Paeonia ostia 'Fengdan' were soaked into MEL solution at concentrations of 50, 100, 200, and 400 µM for 48 h and then germinated in darkness in incubators. Seeds immersed in distilled water without MEL for the same time were served as the control group. Results: At concentrations of 100 and 200 µM, MEL treatments improved the rooting rate of peony seeds, while 400 µM inhibited the process. During seed germination, the 100 and 200 µM MEL treatments significantly reduced the starch concentration, and α-amylase was the primary amylase involved in the action of melatonin. Additionally, compared to the control group, 100 µM MEL treatment significantly increased the GA3 concentration and radicle thickness of seeds, but decreased ABA concentration. The promotion effect of 200 µM MEL pretreatment on GA1 and GA7 was the most pronounced, while GA4 concentration was most significantly impacted by 50 µM and 100 µM MEL. Conclusion: Correlation analysis established that 100 µM MEL pretreatment most effectively improved the rooting rate characterized by increasing α-amylase activity to facilitate starch decomposition, boosting GA3 levels, inhibiting ABA production to increase the relative ratio of GA3 to ABA. Moreover, MEL increased radicle thickness of peony seeds correlating with promoting starch decomposition and enhancing the synthesis of GA1 and GA7.

Exogenous strigolactones alleviate low-temperature stress in peppers seedlings by reducing the degree of photoinhibition.

BACKGROUND: The growth and yield of pepper, a typical temperature-loving vegetable, are limited by low-temperature environments. Using low-temperature sensitive 'Hangjiao No. 4' (Capsicum annuum L.) as experimental material, this study analyzed the changes in plant growth and photosynthesis under different treatments: normal control (NT), low-temperature stress alone (LT), low-temperature stress in strigolactone pretreated plants (SL_LT), and low-temperature stress in strigolactone biosynthesis inhibitor pretreated plants (Tis_LT). RESULTS: SL pretreatment increased the net photosynthetic rate (Pn) and PSII actual photochemical efficiency (φPSII), reducing the inhibition of LT on the growth of pepper by 17.44% (dry weight of shoot). Due to promoting the accumulation of carotenoids, such as lutein, and the de-epoxidation of the xanthophyll cycle [(Z + A)/(Z + A + V)] by strigolactone after long-term low-temperature stress (120 h), non-photochemical quenching (NPQ) of pepper was increased to reduce the excess excitation energy [(1-qP)/NPQ] and the photoinhibition degree (Fv/Fm) of pepper seedlings under long-term low-temperature stress was alleviated. Twelve cDNA libraries were constructed from pepper leaves by transcriptome sequencing. There were 8776 differentially expressed genes (DEGs), including 4473 (51.0%) upregulated and 4303 (49.0%) downregulated genes. Gene ontology pathway annotation showed that based on LT, the DEGs of SL_LT and Tis_LT were significantly enriched in the cellular component, which is mainly related to the photosystem and thylakoids. Further analysis of the porphyrin and chlorophyll biosynthesis, carotenoid biosynthesis, photosynthesis-antenna protein, and photosynthetic metabolic pathways and the Calvin cycle under low-temperature stress highlighted 18, 15, 21, 29, and 31 DEGs for further study, which were almost all highly expressed under SL_LT treatment and moderately expressed under LT treatment, whereas Tis_LT showed low expression. CONCLUSION: The positive regulatory effect of SLs on the low-temperature tolerance of pepper seedlings was confirmed. This study provided new insights for the development of temperature-tolerant pepper lines through breeding programs.

Regulation of seed soaking with indole-3-butyric acid potassium salt (IBA-K) on rapeseed (Brassica napus L.) seedlings under NaCl stress.

The growth and yield of rapeseed are significantly hampered by salt stress. Indole-3-butyric Acid Potassium Salt (IBA-K) has been found to alleviate the impact of salt stress on plant growth. However, the regulatory effect of IBA-K dipping on salt-stressed rapeseed remains unclear. To explore the implications of IBA-K on the growth and development of rapeseed during the seedling stage, we conducted potting experiments using the Huayouza 62 variety. Five different concentrations of IBA-K for seed soaking (0, 10, 20, 40, 80 mg·L- 1) were tested. The promotional impact of IBA-K on rapeseed demonstrated an initial increase followed by a decline, reaching a peak at 20 mg·L- 1. Therefore, 20 mg·L- 1 was determined as the optimal concentration for subsequent experiments. To further understand the mechanism of IBA-K's action on salt-stressed rapeseed seedlings, we utilized the moderately salt-resistant cabbage rapeseed variety Huayouza 158R and the highly salt-resistant Huayouza 62 as specimens. The investigation focused on their response and repair mechanisms under 150 mmol·L- 1 NaCl stress. The findings demonstrated that compared with the sole NaCl stress, the 20 mg·L- 1 IBA-K seed soaking treatment under salt stress significantly enhanced the plant height, stem diameter, and leaf area of both rapeseed varieties. It also led to greater biomass accumulation, increased chlorophyll content, and improved photosynthetic efficiency in rapeseed. Furthermore, this treatment bolstered the activity of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), while significantly reducing the levels of electrolyte leakage (EL) and malondialdehyde (MDA). Consequently, it alleviated the membrane lipid peroxidation damage induced by NaCl stress, enhanced the accumulation of soluble proteins, maintained cellular osmotic pressure, and effectively mitigated the adverse effects of NaCl stress on rapeseed.

Responses to exogenous elicitor treatment in lead-stressed Oryza sativa L.

Heavy metal toxicity adversely affects plants by changing physiological, biochemical, and molecular mechanisms. Lead (Pb) is one of the most common heavy metal pollutants. Hence this study investigated changes caused by exogenous methyl jasmonate (MeJA; 20 and 100 µM) and salicylic acid (SA; 2 and 20 mM) elicitors in local Karacadag rice exposed to Pb stress (0, 100, and 400 ppm). The effects of elicitors on photosynthetic pigment content (chlorophyll a, chlorophyll b, and total carotenoid), proline, malondialdehyde (MDA), total phenolic and flavonoid, Pb, and total protein contents in stressed plants were evaluated. All parameters studied increased and decreased at varying rates in the treatment groups compared to the Pb-free group (control), indicating that rice plants were affected by Pb stress. The elicitors (MeJA, SA, and MeJA + SA) were applied by foliar spraying. The elicitor treatments increased photosynthetic pigment content, total protein, proline, total flavonoid, and phenolic contents depending on the elicitor type and concentration. MDA and Pb contents, increasing with Pb toxicity, decreased with elicitor treatments, and the stress degree was reduced. When the elicitors were compared, SA was more effective than MeJA in total flavonoid content at 400 ppm Pb toxicity. However, MeJA was more effective in photosynthetic pigment contents, MDA, total protein, Pb, total phenolic, and proline contents. The best results for all parameters examined in rice plants exposed to Pb toxicity were obtained from the 400 ppm Pb + 2 mM SA + 20 µM MeJA treatment group. In conclusion, this study showed that the combined application of MeJA + SA alleviated the harmful effects of Pb by reducing MDA and increasing photosynthetic pigments, total protein, proline, and secondary metabolites, especially at high Pb concentrations. Consequently, this study demonstrated that the combined use of MeJA and SA in rice plants eliminated the negative effects of stress quite effectively, even at high Pb concentrations. Therefore, future studies should focus on the synergistic application of different elicitors to better understand the effects of heavy metal toxicity on plant growth and development.

Genome-wide identification, expression pattern and interacting protein analysis of INDETERMINATE DOMAIN (IDD) gene family in Phalaenopsis equestris.

The plant-specific INDETERMINATE DOMAIN (IDD) gene family is important for plant growth and development. However, a comprehensive analysis of the IDD family in orchids is limited. Based on the genome data of Phalaenopsis equestris, the IDD gene family was identified and analyzed by bioinformatics methods in this study. Ten putative P. equestris IDD genes (PeIDDs) were characterized and phylogenetically classified into two groups according to their full amino acid sequences. Protein motifs analysis revealed that overall structures of PeIDDs in the same group were relatively conserved. Its promoter regions harbored a large number of responsive elements, including light responsive, abiotic stress responsive elements, and plant hormone cis-acting elements. The transcript level of PeIDD genes under cold and drought conditions, and by exogenous auxin (NAA) and abscisic acid (ABA) treatments further confirmed that most PeIDDs responded to various conditions and might play essential roles under abiotic stresses and hormone responses. In addition, distinct expression profiles in different tissues/organs suggested that PeIDDs might be involved in various development processes. Furthermore, the prediction of protein-protein interactions (PPIs) revealed some PeIDDs (PeIDD3 or PeIDD5) might function via cooperating with chromatin remodeling factors. The results of this study provided a reference for further understanding the function of PeIDDs.

Impact of salt strength on in vitro propagation and rebaudioside A content in Stevia rebaudiana under semi-solid and liquid MS media.

Stevia rebaudiana (Bertoni), commonly known as stevia, is a sought-after natural sweetener, but its conventional propagation methods are slow and inefficient. This study aims to enhance the in vitro culture for stevia by investigating the impact of different Murashige and Skoog (MS) medium salt strengths and plant growth hormones on growth and rebaudioside A content. Apical bud-containing shoot segments were used as explants and cultured on various semi-solid and liquid MS media formulations, incorporating cytokinins (BAP and Kin), auxins (NAA and IAA), and different MS major salt concentrations (MS full, ½ MS, and » MS). Assessments of shoot growth parameters, root formation, and HPLC analysis for rebaudioside A content were conducted. The optimal conditions for in vitro growth was found to be in the » MS + Kin 3 mg/L + NAA 0.1 mg/L (semi-solid) medium, resulting in significantly improved shoot growth and enhanced 30.04% rebaudioside A content. Genetic fidelity of regenerated plants was confirmed using RAPD and ISSR markers. These findings offer valuable insights for optimizing in vitro propagation of stevia and potentially enhancing rebaudioside A content.

Suprathreshold Water Spray Stimulus Enhances Plant Defenses against Biotic Stresses in Tomato.

Mechanical stimuli can affect plant growth, development, and defenses. The role of water spray stimulation, as a prevalent mechanical stimulus in the environment, in crop growth and defense cannot be overlooked. In this study, the effects of water spray on tomato plant growth and defense against the chewing herbivore Helicoverpa armigera and necrotrophic fungus Botrytis cinerea were investigated. Suprathreshold water spray stimulus (LS) was found to enhance tomato plant defenses against pests and pathogens while concurrently modifying plant architecture. The results of the phytohormone and chemical metabolite analysis revealed that LS improved the plant defense response via jasmonic acid (JA) signaling. LS significantly elevated the level of a pivotal defensive metabolite, chlorogenic acid, and reduced the emissions of volatile organic compounds (VOCs) from tomato plants, thereby defending against pest and pathogen attacks. The most obvious finding to emerge from this study is that LS enhances tomato plant defenses against biotic stresses, which will pave the way for further work on the application of mechanical stimuli for pest management.

Analysis of auxin responses in the fern Ceratopteris richardii identifies the developmental phase as a major determinant for response properties.

The auxin signaling molecule regulates a range of plant growth and developmental processes. The core transcriptional machinery responsible for auxin-mediated responses is conserved across all land plants. Genetic, physiological and molecular exploration in bryophyte and angiosperm model species have shown both qualitative and quantitative differences in auxin responses. Given the highly divergent ontogeny of the dominant gametophyte (bryophytes) and sporophyte (angiosperms) generations, however, it is unclear whether such differences derive from distinct phylogeny or ontogeny. Here, we address this question by comparing a range of physiological, developmental and molecular responses to auxin in both generations of the model fern Ceratopteris richardii. We find that auxin response in Ceratopteris gametophytes closely resembles that of a thalloid bryophyte, whereas the sporophyte mimics auxin response in flowering plants. This resemblance manifests both at the phenotypic and transcriptional levels. Furthermore, we show that disrupting auxin transport can lead to ectopic sporophyte induction on the gametophyte, suggesting a role for auxin in the alternation of generations. Our study thus identifies developmental phase, rather than phylogeny, as a major determinant of auxin response properties in land plants.

Multiomics Combined with Expression Pattern Analysis Reveals the Regulatory Response of Key Genes in Potato Jasmonic Acid Signaling Pathways to Cadmium Stress.

Jasmonic acid (JA) is an endogenous phytohormone that regulates plant physiological metabolism and stress response processes, either independently or through hormone crosstalk. Our phytohormone assay and transcriptome-metabolome analysis revealed the key genes and metabolites involved in the JA pathway in response to 0-250 µM cadmium (Cd) in potato seedlings. Transcriptome gene set enrichment and gene ontology analysis indicated that JA-related genes were significantly enriched. Specifically, members from the StOPR and StJAZ gene families showed pronounced responses to Cd stress and methyl jasmonate treatment. As a negative regulatory transcription factor of the JA signaling pathway, StJAZ14 exhibited a decreasing trend under Cd stress. Yeast two-hybrid assay identified an interaction between StJAZ14 and StBZR1, which is located on the brassinolide pathway. In addition to unveiling the critical role of the JA pathway in regulating potato response to Cd stress, the functional mechanism was preliminarily explored.

Genome-Wide Identification and Characterization of RopGEF Gene Family in C4 Crops.

In plants, RopGEF-mediated ROP signaling is pivotal in cellular signaling pathways, including apical growth, pollen germination and perception, intercellular recognition, as well as in responses to biotic and abiotic stresses. In this study, we retrieved a total of 37 RopGEF members from three C4 Crops, of which 11 are from millet, 11 from sorghum, and 15 from maize. Based on their phylogenetic relationships and structural characteristics, all RopGEF members are classified into four subfamilies. The qRT-PCR technique was utilized to evaluate the expression profiles of 11 SiRopGEFs across different tissues in foxtail millet. The findings indicated that the majority of the SiRopGEFs exhibited higher expression levels in leaves as opposed to roots and stems. The levels of expression of SiRopGEF genes were examined in response to abiotic stress and plant hormones. SiRopGEF1, SiRopGEF5, SiRopGEF6, and SiRopGEF8 showed significant induction under abiotic stresses such as salt, cold, and heat. On the other hand, SiRopGEF1, SiRopGEF2, and SiRopGEF7 were consistently upregulated, while SiRopGEF3, SiRopGEF4, SiRopGEF6, SiRopGEF9, and SiRopGEF10 were downregulated upon exposure to abscisic acid (ABA), ethylene (ET), salicylic acid (SA), and gibberellic acid (GA3) hormones. The alterations in the expression patterns of RopGEF members imply their potential functions in plant growth and development, abiotic stress response, and hormone signal transduction. These discoveries suggest that the RopGEF genes may function as a potential genetic marker to facilitate future studies in elucidating the functional characteristics of RopGEFs.

Choosing an appropriate somatic embryogenesis medium of carrot (Daucus carota L.) by data mining technology.

INTRODUCTION: Developing somatic embryogenesis is one of the main steps in successful in vitro propagation and gene transformation in the carrot. However, somatic embryogenesis is influenced by different intrinsic (genetics, genotype, and explant) and extrinsic (e.g., plant growth regulators (PGRs), medium composition, and gelling agent) factors which cause challenges in developing the somatic embryogenesis protocol. Therefore, optimizing somatic embryogenesis is a tedious, time-consuming, and costly process. Novel data mining approaches through a hybrid of artificial neural networks (ANNs) and optimization algorithms can facilitate modeling and optimizing in vitro culture processes and thereby reduce large experimental treatments and combinations. Carrot is a model plant in genetic engineering works and recombinant drugs, and therefore it is an important plant in research works. Also, in this research, for the first time, embryogenesis in carrot (Daucus carota L.) using Genetic algorithm (GA) and data mining technology has been reviewed and analyzed. MATERIALS AND METHODS: In the current study, data mining approach through multilayer perceptron (MLP) and radial basis function (RBF) as two well-known ANNs were employed to model and predict embryogenic callus production in carrot based on eight input variables including carrot cultivars, agar, magnesium sulfate (MgSO4), calcium dichloride (CaCl2), manganese (II) sulfate (MnSO4), 2,4-dichlorophenoxyacetic acid (2,4-D), 6-benzylaminopurine (BAP), and kinetin (KIN). To confirm the reliability and accuracy of the developed model, the result obtained from RBF-GA model were tested in the laboratory. RESULTS: The results showed that RBF had better prediction efficiency than MLP. Then, the developed model was linked to a genetic algorithm (GA) to optimize the system. To confirm the reliability and accuracy of the developed model, the result of RBF-GA was experimentally tested in the lab as a validation experiment. The result showed that there was no significant difference between the predicted optimized result and the experimental result. CONCLUTIONS: Generally, the results of this study suggest that data mining through RBF-GA can be considered as a robust approach, besides experimental methods, to model and optimize in vitro culture systems. According to the RBF-GA result, the highest somatic embryogenesis rate (62.5%) can be obtained from Nantes improved cultivar cultured on medium containing 195.23 mg/l MgSO4, 330.07 mg/l CaCl2, 18.3 mg/l MnSO4, 0.46 mg/l 2,4- D, 0.03 mg/l BAP, and 0.88 mg/l KIN. These results were also confirmed in the laboratory.