Gibberellic Acid Treatment Research Articles

Non-Deep Simple Morphophysiological Dormancy and Germination Characteristics of Gentiana triflora var. japonica (Kusn.) H. Hara (Gentianaceae), a Rare Perennial Herb in Korea

This study investigated the kind of seed dormancy and seed germination of Gentiana triflora var. japonica (Kusn.) H. Hara for developing a seed propagation method. The seeds were collected in October 2020 from plants at Mt. Sobaeksan, Korea. In a water imbibition experiment, seed weights increased by >101.9% of their initial masses over 12 h. Effects of incubation temperature (5, 15, 20, 25, 15/6, or 25/15 °C), cold stratification period (5 °C; 0, 4, 8, or 12 weeks), and gibberellic acid (GA3; 0, 10, 100, or 1000 mg∙L−1) and potassium nitrate treatment (KNO3; 0, 1000, 2000, or 4000 mg∙L−1) on seed germination were investigated to characterize seed dormancy. These seeds exhibited underdeveloped embryos during seed dispersal. The seeds failed to reach the final germination of 15.0% after treatment at 5, 15, 20, 25, 15/6, or 25/15 °C. After cold stratification for 8 weeks, the germination increased dramatically by >90.0% compared to that at 0 weeks. After the GA3 treatment, the germination reached >80.0% within 5 days. The final germination was 90.0% in the 100 mg∙L−1 GA3 treatment group. However, the KNO3 treatment had no effect on seed germination. Therefore, the G. triflora var. japonica seeds exhibited non-deep simple morphophysiological dormancy.

Gibberellic acid maintains postharvest quality of Agaricus bisporus mushroom by enhancing antioxidative system and hydrogen sulfide synthesis.

The application of gibberellic acid (GA3 ) treatment to the postharvest quality maintenance of white button mushroom (Agaricus bisporus) was investigated. The optimum concentration of exogenous GA3 was 100mg/L. At this concentration, the color change was inhibited, the firmness was maintained, and the weight loss and respiratory rates were reduced. The GA3 group had significantly lower malonaldehyde (MDA) content and membrane permeability. Reactive oxygen species accumulation was reduced due to the regulation of polyphenol oxidase (PPO), peroxidase (POD), and superoxide dismutase (SOD) enzyme activities. Moreover, the production of endogenous gaseous signaling molecule hydrogen sulfide (H2 S) was triggered by GA3 treatment, which enhanced cystathionine γ-lyase (AbCSE) and cystathionine β-synthase (AbCBS) activities alongside the corresponding gene expressions. The preservation of button mushroom postharvest storage quality by GA3 was most likely due to the regulation of reactive oxygen species metabolism and hydrogen sulfide biosynthesis. PRACTICAL APPLICATIONS: Mushroom is rich in nutrients and functional substances. However, due to the lack of cuticle, high respiration rate, and moisture content, mushroom's postharvest quality deteriorates rapidly. A safe and effective reagent that prevents the senescence and quality deterioration of harvested mushroom is urgently needed. The effects of plant hormone GA3 on the postharvest quality of edible fungi remain unclear. The present study provided convincing evidence that 100mgL-1 of GA3 effectively maintained postharvest button mushroom quality by regulating reactive oxygen species metabolism and hydrogen sulfide biosynthesis.

Application of a process-based model to quantifying dormancy loss in seeds of Parrotia persica C.A. Meyer

Information regarding germination and dormancy of Parrotia persica seeds is limited and there is no report on cardinal temperatures and germination modeling of this tree species. Thus, the main aims of this study were to model dormancy and germination of P. persica seeds and to identify the best way(s) to overcome seed dormancy in this species. Freshly matured seeds had spatulate, fully developed embryos (FA1 type) and the seed coat was water permeable. Fresh seeds germinated less than 20% at 5–30 °C, and gibberellic acid (GA) increased germination to about 40% at 5–30 °C, peaking at 53% at at 20 °C. Population thermal parameters (Tl and Th) had changed among dormancy breaking treatments. After-ripened seeds and those treated with GA had the lowest lower limit (Tl) and the highest higher limit temperatures which were 0.0 and 37 °C, respectively. The highest Tl and the lowest Th were observed in freshly matured seeds without any treatments (Control-MT) which were 24 and 26 °C; the narrowest temperature range for germination, implying the highest seed dormancy. Base (Tb) and ceiling (Tc) temperatures for the final germination percentage of non-dormant seeds were 0, and 40°C. Cardinal temperatures for the rate (speed) of germination of non-dormant seeds were almost the same as the observed values for final germination percentage. Seeds of P. persica must have Type 3 of non-deep physiological dormancy based on the graphical method, since Tb decreased and Tc increased as dormancy breaking progresses in a population. Population thermal parameters (Tl and Th) also showed the same change in different dormancy breaking treatments in which dormant seeds had higher Tl and lower Th than non-dormant seeds (after-ripened plus GA). For commercial usage or conservation projects, it is suggested to use a period of after-ripening followed by GA treatment to break dormancy.

Sulfuric Acid and Gibberellic Acid (GA3) Treatment Combined with Exposure to Cold Temperature Modulates Seed Proteins during Breaking of Dormancy to Germination in Tilia miqueliana.

Tilia miqueliana produces woody seeds that exhibit deep dormancy. In this study, we used cell biology methods, including Paraffin section determination and Coomassie brilliant blue staining, as well as proteomics-based methods, including two-dimensional electrophoresis with matrix-assisted laser desorption/ionisation tandem time-of-flight mass spectrometry (2DE-MALDI-TOF/TOF), to examine the effects of H2SO4-GA3 and cold stratification (3°C) treatment on proteins during dormancy release and germination in T. miqueliana seeds. The results revealed that during cold stratification, the area and density of proteins in the endosperm cells of H2SO4-GA3-treated seeds were significantly altered. Total protein content was continuously consumed and utilised. Storage proteins (albumin, globulin, prolamin, and glutelin) were degraded to varying degrees. Sixteen differential proteins were identified using mass spectrometry. Kyoto encyclopedia of genes (KEGG) pathway analysis revealed that the glycolysis/gluconeogenesis, secondary metabolite biosynthesis, glyoxylate and dicarboxylate metabolism, amino acid biosynthesis, and metabolic pathways were critical during dormancy release and germination. Gene ontology analysis and KEGG pathway annotation of differential proteins in the co-expression network indicated that the differential proteins are implicated in photosynthesis, glucose metabolism, biosynthesis of plant hormones, and glycolysis/gluconeogenesis. Synergistic interactions among these proteins accelerated dormancy release and germination. Therefore, H2SO4-GA3 cold stratification treatment is the best method for achieving rapid dormancy release and increasing the germination rate of T. miqueliana seeds.

The Influence of Flower Head Order and Gibberellic Acid Treatment on the Hydroxycinnamic Acid and Luteolin Derivatives Content in Globe Artichoke Cultivars.

Flower head orders and the use of GA3 (gibberellic acid) treatment could be two influencing factors determining the bioactive compound levels in artichoke, but little to no information is available about their effects. In this study, we have therefore evaluated the influence of these factors on the hydroxycinnamic acid and luteolin derivative levels in three categories of artichoke: Seed-propagated open-pollinated cultivars; vegetatively propagated cultivars; and seed-propagated hybrids. The hydroxycinnamic acids and luteolin derivatives were quantified by RP-HPLC-DAD. The average flower head weight was the lowest in tertiary heads and GA3-treated artichokes, followed by secondary and main heads. Moreover, the hydroxycinnamic acid and luteolin derivatives levels were significantly higher in tertiary heads than in secondary or main heads. In addition, the GA3 treatment significantly reduced the hydroxycinnamic acid content and, in contrast, improved luteolin derivatives levels. These effects depended on the flower head order and cultivar. Knowledge of the effects of flower head order and GA3 treatment is therefore key in order to achieve the greatest health-benefits from artichoke consumption.

Morphological and Flowering Characteristics of Shallot (Allium cepa Var. Aggregatum) in Response to Gibberellic Acid and Vernalization

Shallot plants have variations in morphological and flowering characters. Flowering ability can be induced by the treatment of gibberellic acid (GA3) and exposing to cold temperature (vernalization). The objectives of the research were to determine the effect of GA3 and vernalization on the morphological and flowering characters of 5 shallot varieties. Field study was organized in a completely randomized block design with three replications to evaluate the responses of 5 varieties of shallots (Bauji, Bima Brebes, Super Philip, Tajuk, and Thailand) to GA3 with the concentrations ranged from zero to 150 mg L-1. Plants were maintained for 65 days until harvesting. The second study was organized in a completely randomized design with 3 replications to evaluate the responses of the five varieties of shallot to vernalization. The vernalization of shallot bulbs were done at 8 o C for 6 weeks. The results indicated that a Super Phillip variety showed the highest response to GA3 observed in the number of leaves and bulbs. At 100 mg L-1 of GA3 increased the plant height up to 45.74 cm. The results from the second study showed that vernalization was effective to increase flowering only on the Ilokos variety. But the other varieties were not sensitive to vernalization. Based on morphological and flowering characters, 5 varieties of shallots were clustered into 3 groups, namely: sensitive flowering included Bentanis, Bma Brebes and Tajuk variety, medium sensitive flowering included Ilokos variety, and non-sensitive flowering included Sumenep variety.

Pengaruh Konsentrasi dan Lama Perendaman GA3 terhadap Perkecambahan Benih dan Pertumbuhan Bibit Johar (Cassia seamea)

Johar (<em>Cassia seamea</em>) is a medicinal plant with a cassiarin A compound to combat malaria and has a low Cassiarin A is an active compound in Johar (<em>Cassia seamea</em>) medicinal plant capable of combating malaria, despite showing a low seed production rate due to dormancy. This inactivity is severed using gibberellic acid (GA<sub>3</sub>) treatments. This study aims to determine the effects of concentration and soaking period of GA<sub>3</sub> on seed germination and growth of Johar seedlings. A completely randomized design (CRD), consisting of 2 treatments was applied as the research method. The first treatment employed GA<sub>3</sub> concentrations of 0, 45, 90 and 135 ppm, while the second was based on the soaking interval at 6, 12, 18 and 24 hours. The results showed the capacity of GA<sub>3</sub> able to shatter the seed dormancy with percentage germination of 43.03% and a concentration of 50.28 ppm. Therefore, the interaction of the two treatments significantly influenced the growth of Johar seedlings. Consequently, the concentration of GA<sub>3</sub> at 79.89 ppm increased the root length to 52.19 cm, while 84.68 ppm produced a total of 20.91 roots, after a 6 hour soaking. In addition, the 96.67 ppm expanded the stem diameter by 0.93 cm.

CYTOKININ, GIBBERELLIC ACID AND DEFOLIATION ON DENSITY AND MORPHOLOGY OF TRICHOME OF Pelargonium graveolens L’Hér FOR ESSENTIAL OIL BIOSYNTHESIS

The density and morphology of glandular trichomes in rose geranium (Pelargonium graveolens L’Her.) are often correlated to the essential oil biosynthesis. However, whether the different organs in the same rose geranium plant are affected by hail damage, or if they recover similarly following hail damage is still unknown concerning the essential oil biosynthesis. The objective of this study was to evaluate the effects of split-applying cytokinin (CK), gibberellic acid (GA) and defoliation on rose geranium trichome morphology and density, and essential oil biosynthesis. The experiment was carried out in a hail-net covered tunnel structure during 2017-2018 growing season. The experimental design was a complete randomized blocks with a 3x3 factorial arrangement of treatments: three defoliation levels (0, 50, and 100%), two levels of split-application of CK and GA (0.32 mg L-1 CK + 150 mg L-1 GA; and 0.64 mg L-1 CK + 300 mg L-1 GA), and a control. The attenuate, peltate, and capitate trichome groups were identified in the leaf. Morphologically, the attenuate trichome group was less dense on both recovered and new plant leaves, despite split-applied CK and GA treatment. With the peltate group, brevicollate trichome density declined in all plant leaves treated with 0.64 mg L-1 CK + 300 mg L-1 GA on both leaf surfaces. Application of 0.64 mg L-1 CK + 300 mg L-1 GA led to high density of the elongated-capitate type on leaves recovered from 50 and 100% defoliation. The essential oil yield was not affected by density and morphological changes of the trichomes. However, the application of 0.32 mg L-1 CK + 150 mg L-1 GA increased the citronellol content where plants endured 100% defoliation. Results demonstrated that the effects of hail damage stress and subsequent split-applied CK and GA could transform the morphology of trichomes, subsequently increasing the density.

Expression dynamics indicate the role of Jasmonic acid biosynthesis pathway in regulating macronutrient (N, P and K+) deficiency tolerance in rice (Oryza sativa L.).

Expression pattern indicates that JA biosynthesis pathway via regulating JA levels might control root system architecture to improve nutrient use efficiency (NUE) and N, P, K+ deficiency tolerance in rice. Deficiencies of macronutrients (N, P and K+) and consequent excessive use of fertilizers have dramatically reduced soil fertility. It calls for development of nutrient use efficient plants. Plants combat nutrient deficiencies by altering their root system architecture (RSA) to enhance the acquisition of nutrients from the soil. Amongst various phytohormones, Jasmonic acid (JA) is known to regulate plant root growth and modulate RSA. Therefore, to understand the role of JA in macronutrient deficiency in rice, expression pattern of JA biosynthesis genes was analyzed under N, P and K+ deficiencies. Several members belonging to different families of JA biosynthesis genes (PLA1, LOX, AOS, AOC, OPR, ACX and JAR1) showed differential expression exclusively in one nutrient deficiency or in multiple nutrient deficiencies. Expression analysis during developmental stages showed that several genes expressed significantly in vegetative tissues, particularly in root. In addition, JA biosynthesis genes were found to have significant expression under the treatment of different phytohormones, including Auxin, cytokinin, gibberellic acid (GA), abscisic acid (ABA), JA and abiotic stresses, such as drought, salinity and cold. Analysis of promoters of these genes revealed various cis-regulatory elements associated with hormone response, plant development and abiotic stresses. These findings suggest that JA biosynthesis pathway by regulating the level of JA might control the RSA thus, it mayhelp rice plant incombating macronutrient deficiency.

Chlorophyll fluorescence imaging as a tool to evaluate calyx senescence during the ripening of persimmon fruit treated with gibberellic acid

The effect of gibberellic acid (GA) on retarding loss of persimmon firmness and fruit coloration has been previously reported. Nevertheless, information about the effect of this treatment on calyx senescence is lacking. In this study, chlorophyll fluorescence imaging (CFI) was used to evaluate calyx senescence in persimmon fruit treated with GA. At three harvest times, physico-chemical parameters measured on persimmon fruit and CFI parameters (Fo, Fm and Fv/Fm) on calyx sepals were evaluated on the fruit treated once or twice with GA, and also on untreated fruit (CTL). A decline in the chlorophyll fluorescence parameters correlated with calyx senescence and progressed during fruit ripening. Spatial images heterogeneity in the Fm/Fv measurements illustrates senescence and necrosis dynamics, which began in the apical area of sepals and progressed to the basal area. Besides retarding fruit ripening, GA treatments delayed the calyx senescence process, and hence improved external fruit quality maintenance. The CFI parameters measured on the calyx correlated with both external color evolution and firmness loss during fruit ripening. Consequently, these chlorophyll fluorescence parameters could act as a potential non-intrusive tool to determine persimmon harvesting time.

Characterization of BoaCRTISO Reveals Its Role in Carotenoid Biosynthesis in Chinese Kale.

Carotenoids are organic pigments that play an important role in both plant coloration and human health; they are a critical subject in molecular breeding due to growing demand for natural molecules in both food and medicine. In this study, we focus upon characterizing BoaCRTISO, the carotenoid isomerase gene before the branch of the carotenoid biosynthetic pathway, which is expressed in all organs and developmental stages of Chinese kale, and BoaCRTISO, which is located in the chloroplast. The expression of BoaCRTISO is induced by strong light, red and blue combined light, and gibberellic acid treatment, but it is suppressed by darkness and abscisic acid treatment. We obtained BoaCRTISO-silenced plants via virus-induced gene silencing technology, and the silence efficiencies ranged from 52 to 77%. The expressions of most carotenoid and chlorophyll biosynthetic genes in BoaCRTISO-silenced plants were downregulated, and the contents of carotenoids and chlorophyll were reduced. Meanwhile, BoaCRTISO-silenced plants exhibited phenotypes of yellowing leaves and inhibited growth. This functional characterization of BoaCRTISO provides insight for the biosynthesis and regulation of carotenoid in Chinese kale.

Genome-Wide Identification and Expression Analysis of MYB Transcription Factors and Their Responses to Abiotic Stresses in Woodland Strawberry (Fragaria vesca)

Woodland strawberry (Fragaria vesca) is a diploid strawberry that is widely used as a model of cultivated octoploid strawberry (Fragaria × ananassa). It has also been used as a model for Rosaceae fruits, non-climacteric fruits, and stolons. The MYB superfamily is the largest transcription factor family in plants, and its members play important roles in plant growth and development. However, the complete MYB superfamily in woodland strawberry has not been studied. In this study, a total of 217 MYB genes were identified in woodland strawberry and classified into four groups: one 4R-MYB protein, five 3R-MYB proteins, 113 2R-MYB proteins, and 98 1R-MYB proteins. The phylogenetic relationship of each MYB subgroup was consistent in terms of intron/exon structure and conserved motif composition. The MYB genes in woodland strawberry underwent loss and expansion events during evolution. The transcriptome data revealed that most FveMYB genes are expressed in several organs, whereas 15 FveMYB genes exhibit organ-specific expression, including five genes (FveMYB101, -112, -44, and -8; FveMYB1R81) in roots, two genes (FveMYB62 and -77) in stolon tips, three genes (FveMYB99 and -35; FveMYB1R96) in open flowers, and five genes (FveMYB76 and -100; FveMYB1R4, -5, and -86) in immature fruits. During fruit ripening of woodland strawberry, the expression levels of 84 FveMYB genes were decreased, of which five genes (FveMYB4, -22, -50, and -66; FveMYB1R57) decreased more than 10-fold, whereas those 18 FveMYB genes were increased, especially FveMYB10 and FveMYB74 increased more than 30-fold. In addition, the expression levels of 36, 68, 52, and 62 FveMYB genes were altered by gibberellic acid, abscisic acid, cold, and heat treatments, respectively, and among them, several genes exhibited similar expression patterns for multiple treatments, suggesting possible roles in the crosstalk of multiple signaling pathways. This study provides candidate genes for the study of stolon formation, fruit development and ripening, and abiotic stress responses.

Fine Mapping of Cla015407 Controlling Plant Height in Watermelon

The plant compact and dwarf growth habit is an important agronomic trait when breeding watermelon (Citrullus lanatus) cultivars because of their reduced vine length, high-density planting, and better land utilization; however, the genetic basis of the dwarf growth habit is not well-known. In this study, the plant population of six generations, P1, P2, F1, F2, BC1P1, and BC1P2, were studied. A genetic segregation analysis demonstrated that dwarfism is mainly controlled by a single recessive Cldw gene. Furthermore, whole-genome sequencing of two distinct watermelon cultivars, W1-1 (P1) and 812 (P2), was performed and preliminarily mapped through a bulked segregant analysis of F2 individuals that revealed the Cldw gene locus on chromosome 9. Two candidate genes, Cla015407 and Cla015408, were discovered at the delimited region of 43.2 kb by fine mapping, and gene annotation exposed that the Cla015407 gene encodes gibberellic acid 3β-hydroxylase protein. In addition, a comparative analysis of gene sequence and cultivars sequences across the reference genome of watermelon revealed the splice site mutation in the intron region of the Cldw gene in dwarf-type cultivar 812. The quantitative real-time polymerase chain reaction exhibited a significantly higher expression of the Cla015407 gene in cultivar W1-1 compared with 812. There was no significant difference in the vine length of both cultivars after gibberellic acid treatment. In brief, our fine mapping demonstrated that Cla015407 is a candidate gene controlling dwarfism of watermelon plants.

Effects of exogenous phytohormones on chlorogenic acid accumulation and pathway-associated gene expressions in sweetpotato stem tips

Sweetpotato (Ipomoea batatas [L.] Lam.) stem tips, which contain high concentrations of chlorogenic acid (CGA), are useful as a physiologically functional food to protect against some serious diseases. According to previous studies, exogenous application of phytohormones may be an effective agrotechnical measure to control CGA biosynthesis through the transcriptional regulation of pathway gene expressions. To understand the mechanism of CGA biosynthesis in sweetpotato, we investigated the effects of exogenous phytohormones on CGA metabolism in stem tips of sweetpotato. A significantly elevated CGA content was observed in salicylic acid (SA)-treated sweetpotato stem tips at 72 h, as well as in those subjected to abscisic acid (ABA) or gibberellic acid (GA) treatments. Dynamic expression change of seven enzyme genes involved in sweetpotato CGA biosynthesis were analyzed to determine correlations between transcript levels and CGA accumulation. As revealed by the differential expression of these genes under distinct phytohormone treatments, the regulation of specific pathway genes is a critical determinant of the accumulation of CGA in sweetpotato stem tips. We also found that several hormone-responsive sites, such as those for ABA, GA, SA, and jasmonic acid (JA), were present in the promoter regions of sweetpotato CGA biosynthestic pathway genes. Collectively, phytohormones can regulate the transcription of CGA synthesis-related genes and ultimately affect CGA accumulation in sweetpotato stem tips, whereas the regulatory differences are mirrored by cis-acting elements in the corresponding pathway gene promoters.

Effects of exogenous gibberellic acid on growth and cadmium accumulation in Cyphomandra betacea seedlings

AbstractThe contamination of orchards by the heavy metal cadmium (Cd) is a serious problem partly because of the toxicity of the Cd accumulated in fruits. Accordingly, developing suitable methods for minimizing the toxic effects of Cd on plants is necessary. In the current study, a pot‐based experiment was conducted to assess the effects of various concentrations (0, 100, 200, 300, and 400 mg/L) of exogenous gibberellic acid (GA) on the growth and Cd accumulation in Cyphomandra betacea seedlings. The GA treatments promoted C. betacea seedling growth and increased the biomass as well as the chlorophyll, carotenoid, and soluble sugar contents. Additionally, the application of GA, especially the 300 mg/L solution, enhanced the net photosynthetic rate, stomatal conductance, the intercellular CO2 concentration, the transpiration rate, and the peroxidase, superoxide dismutase, and catalase activities. In contrast, the Cd content of C. betacea seedlings gradually decreased in response to increasing exogenous GA concentrations. Thus, the application of a GA solution improved C. betacea seedling growth and decreased the toxicity of Cd, with 300 mg/L representing the most effective GA concentration.

Hydrogen-rich water alleviates programmed cell death induced by GA in wheat aleurone layers by modulation of reactive oxygen species metabolism

Hydrogen gas (H2) has been recently regarded as a novel gaseous signaling molecule that performs multiple functional roles in plant. Here, we demonstrate that hydrogen rich water (HRW)—an experimentally tractable reagent to assess the effects of the H2 significantly delays wheat aleurone layer programmed cell death (PCD) induced by gibberellic acid (GA). Endogenous H2 production exhibited lower level in aleurone layers under GA treatment, whereas the H2 production was apparently increased under abscisic acid (ABA) treatment. HRW not only increased H2 production but also delayed GA-induced PCD. We further observed that application of HRW substantially prevented the increases of hydrogen peroxide (H2O2) and superoxide anion radical (O2.-) triggered by GA. HRW also directly react with hydroxyl radical (·OH) to delay GA-induced PCD. Quantitative real-time PCR (qRT-PCR) and biochemical assays showed that HRW induced the transcripts and enzymatic activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT) that metabolize reactive oxygen species (ROS); these increases coincided with the observed changes in O2.-, H2O2 and ·OH accumulation upon GA treatment. Our study therefore suggests that HRW-triggered alleviation of wheat aleurone layer PCD induced by GA results from a combination of H2-mediated decreases of ROS levels, including O2.-, H2O2, and ·OH.

Catalase (CAT) Gene Family in Rapeseed (Brassica napus L.): Genome-Wide Analysis, Identification, and Expression Pattern in Response to Multiple Hormones and Abiotic Stress Conditions.

Catalase (CAT) is an antioxidant enzyme expressed by the CAT gene family and exists in almost all aerobic organisms. Environmental stresses induce the generation of reactive oxygen species (ROS) that eventually hinder plant growth and development. The CAT enzyme translates the hydrogen peroxide (H2O2) to water (H2O) and reduce the ROS levels to shelter the cells’ death. So far, the CAT gene family has not been reported in rapeseed (Brassica napus L.). Therefore, a genome-wide comprehensive analysis was conducted to classify the CAT genes in the rapeseed genome. The current study identified 14 BnCAT genes in the rapeseed genome. Based on phylogenetic and synteny analysis, the BnCATs belong to four groups (Groups I–IV). A gene structure and conserved motif analysis showed that Group I, Group II, and Group IV possess almost the same intron/exon pattern, and an equal number of motifs, while Group III contains diverse structures and contain 15 motifs. By analyzing the cis-elements in the promoters, we identified five hormone-correlated responsive elements and four stress-related responsive elements. Further, six putative bna-miRNAs were also identified, targeting three genes (BnCAT4, BnCAT6, and BnCAT8). Gene ontology (GO) enrichment analysis showed that the BnCAT genes were largely related to cellular organelles, ROS response, stimulus response, stress response, and antioxidant enzymes. Almost 10 BnCAT genes showed higher expression levels in different tissues, i.e., root, leaf, stem, and silique. The expression analysis showed that BnCAT1–BnCAT3 and BnCAT11–BnCAT13 were significantly upregulated by cold, salinity, abscisic acid (ABA), and gibberellic acid (GA) treatment, but not by drought and methyl jasmonate (MeJA). Notably, most of the genes were upregulated by waterlogging stress, except BnCAT6, BnCAT9, and BnCAT10. Our results opened new windows for future investigations and provided insights into the CAT family genes in rapeseed.

Dormancy-breaking and germination requirements of Thalictrum squarrosum Stephan ex Willd. seeds with underdeveloped embryos

The timing of seed germination has a significant effect on the life cycles and fitness of plants. Thalictrum squarrosum is a perennial herb with medical and ornamental value. However, the dormancy type and the regeneration strategy it uses to adapt to the natural habitat have yet to be investigated. The present study determined the seed germination requirements of T. squarrosum seeds and characterized the type of seed dormancy observed in this species. The results indicate that seeds of T. squarrosum had differentiated but underdeveloped embryos. After 30 days of incubation under 5/15, 10/20, 15/25, and 20/30 °C in light/dark conditions, no seed germination was observed, which indicated that the seeds had a morphophysiological type of dormancy. After 12 weeks of cold stratification, > 90 % seeds germinated at 5/15 and 10/20 °C. In addition, a gibberellic acid (GA3) treatment can substitute for the need for cold stratification and successfully broke dormancy in T. squarrosum seed. Seeds treated with 1000 mg/L GA3 had higher germination rates than those treated with 10 or 100 mg/L GA3. Embryo growth and germination began in February under natural conditions of the year following production. We conclude that T. squarrosum seed exhibits non-deep simple morphophysiological dormancy. These findings will enhance our understanding of the regeneration strategy of T. squarrosum that allows it to adapt to the environment and will offer a reference to horticulturalists and seed ecologists in understanding the germination processes of T. squarrosum.

Different Reaction of Biosynthetic System of Human Dermal Fibroblasts and Fibrosarcoma Cells to Plant Hormones

Plant hormones are signal molecules regulating plant growth and development. Some plant hormones are known as medicine, while the effect of other hormones is less known and therefore needs to be characterized. The aim of this study was to investigate the effect of 2 mM concentration of plant hormones abscisic acid (ABA) and gibberellic acid (GA) on the biosynthetic system (endoplasmic reticulum (ER), Golgi apparatus, acidic compartment vesicles) of cultured human dermal fibroblasts and HT1080 human fibrosarcoma cells. Using light and electron microscopy, we demonstrated that the components of the biosynthetic system of these cell lines reacted differently to ABA and GA. In particular, the expansion of ER cisternae was observed in dermal fibroblasts after exposure to GA, but in fibrosarcoma cells – after exposure to ABA. The redistribution of the Golgi apparatus around the nucleus occurred in dermal fibroblasts after both ABA and GA treatment, but was not observed in fibrosarcoma cells. However, the expansion of Golgi apparatus cisternae was observed in fibrosarcoma cells after ABA treatment. The changes of acidic compartment vesicles were observed in dermal fibroblasts after incubation with ABA and only on the ultrastructural level, and displayed as the appearance of numerous vesicles with multilayered content in the lumen. On the contrary, in fibrosarcoma cells the differences were revealed after both ABA and GA treatment and were detected by lysotracker staining. Thus, the response of the biosynthetic system in the connective-tissue cells to ABA and GA differs in normal and tumor cell lines, and also from the response described previously for the cells of epidermoid origin.

Cytokinin but not gibberellin application had major impact on the phenylpropanoid pathway in grape

Cytokinin and gibberellic acid (GA) are growth regulators used to increase berry size in seedless grapes and it is of interest to understand their effects on the phenylpropanoid pathway and on ripening processes. GA3 and synthetic cytokinin forchlorfenuron (N-(2-chloro-4-pyridyl)-N′-phenylurea, CPPU) and their combination were applied to 6 mm diameter fruitlets of ‘Sable Seedless’, and berries were sampled 51 and 70 days (d) following application. All treatments increased berry size and delayed sugar accumulation and acid degradation with a stronger effect of CPPU. CPPU, but not GA, reduced berry color and the levels of anthocyanins. While CPPU reduced the levels of anthocyanins by more than 50%, the combined treatment of GA+CPPU reduced the levels by about 25% at 51 d. CPPU treatment had minor effects on flavonols content but increased the levels of monomeric flavan-3-ols by more than two-fold. Phloroglucinol analysis using HPLC showed that proanthocyanidin content was significantly increased by CPPU, whereas mean degree of polymerization was reduced from 26 to 19. Volatile analysis by GC-MS showed changes in composition with CPPU or GA treatment with potential impact on flavor. RNA-seq analysis showed that GA had a minor overall effect on the transcriptome whereas CPPU had pronounced effects on gene expression at both 51 and 70 d. Comparing the control and CPPU at similar Brix of ca. 19.7°, a reduced expression of stilbene synthases (STSs) including their regulators MYB14 and MYB15, and other phenylpropanoid-related genes was observed in CPPU-treated grapes. Overall, our study shows that CPPU had a major influence on the phenylpropanoid pathway and affected multiple ripening-related processes.