Zeatin Riboside Research Articles

Comparing Rooting Ability and Physiological Changes of Two Eucommia ulmoides Improved Varieties

Eucommia ulmoides (E. ulmoides) is a significant national strategic resource in China. It is a natural high quality rubber resource, with great development potential. We found large differences in rooting ability during adventitious root (AR) formation in two E. ulmoides improved varieties. Therefore, we used two improved varieties of E. ulmoides, ‘Huazhong 6’ (H6, with rooting rate 85.3%) and ‘Huazhong 8’ (H8, with rooting rate 22.5%) to explore the cutting rooting mechanism. In this study, we mainly determined the morphological development process of E. ulmoides cutting rooting, and compared the rooting-related indexes of the two improved varieties, and the changes in physiological indexes closely related to rooting, which include endogenous hormones, oxidases and nutrients in the phloem of the basal stem. The results showed that indole–3–acetic acid (IAA), zeatin riboside (ZR), IAA/ZR and indoleacetic acid oxidase (IAAO) were the key factors that caused big differences in rooting ability between the two E. ulmoides improved varieties. The increase in endogenous hormone IAA content and IAA/ZR value were necessary for the formation of AR. The increase in IAA content was beneficial to AR formation. The activity of IAAO was significantly negatively correlated with the rooting ability of the E. ulmoides cuttings. The high IAAO activity of the H8 cuttings led to the consumption of IAA. Although the content of IAA increased, the rooting conditions were not reached. The accumulation of nutrients before rooting also has an important effect on rooting; it is easy for cuttings to root when the carbon–nitrogen ratio (C/N) value is high. This research provides an improved understanding of the cellular and physiological underpinnings of the AR process in woody plants. In addition, it provides a theoretical basis and foundation for subsequent research on E. ulmoides cuttage technology.

Uncovering the mechanism preliminarily of formation and development of taro corm in vitro by morphological physiology and transcriptomic analysis

In vitro virus-free corms as propagules provide a feasible alternative to the convenient transport and the high survival rate of transplant for typical asexual crop of taro (Colocasia esculenta (L.) Schott). However, the mechanism of formation and expansion of in vitro corm remains unclear. In this study, in vitro corms were obtained from virus-free test-tube plantlet of taro in optimized induced medium (Murashige-Skoog medium + 2 mg L−1 6-Benzylaminopurine + 0.5 mg L−1 1-naphthalene acetic acid + 3% sucrose) (OIM), and then inoculated into the medium with Murashige-Skoog medium + 8% sucrose (MS8) for corm expansion. During this process, morphological observations by paraffin section, plant growth regulators (PGRs) content determination by enzyme-linked immunosorbent assay, and transcriptome assay by Illumina platform were carried out at days 0 (T0), 45 (T1), 90 (T2), and 135 (T3) under different corm expansion stages. The results showed that parenchymal cells enlarge continuously, accompanied with starch particles increase during corm expansion. Besides, three PGRs of indoleacetic acid (IAA), zeatin-riboside (ZR), and abscisic acid (ABA) were positively correlated with corm expansion, the contents of IAA and ABA remained at a high level. Moreover, the transcriptome results showed that plant hormone signal transduction and the starch and sucrose metabolism pathways are enriched significantly based on Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. The genes (SBE2.2, GBSS, SUS4), related to starch biosynthesis were up-regulated, meanwhile, three genes of AMYs involved in starch metabolism were down-regulated, which probably promote starch accumulation and corms expansion. Eight genes from plant hormone signal transduction and the starch and sucrose metabolism pathway were selected randomly to validate the result of RNA-seq, and the RT-qPCR results were consistent with the RNA-seq data. These results will provide valuable information for uncovering the mechanism of in vitro corm expansion.

Effects of Endogenous Hormones and Sugars on Fruit Size Driven by Cell Division between Korla Fragrant Pear and Its Bud Mutation

Large-fruit bud mutations are important factors in fruit tree breeding. However, little is known about the differences between varieties and bud mutations. The ploidy identification of Korla fragrant pear (Pyrus sinkiangensis Yu) and its large bud mutation Zaomeixiang pear showed that the large-fruit characteristic was not caused by chromosome doubling. By counting mesocarp cells at different stages, we found that the number of cells increased continuously after pollination, and the difference was the greatest at 28 days after full bloom (DAFB), and was about 9.4 × 106. After 28 days, the difference in cell volume became bigger and bigger, so both the cell volume and cell number caused the difference in fruit size between Korla fragrant pear and Zaomeixiang pear. To obtain more insights into the differences in fruit size driven by cell division, we analyzed the endogenous hormones [indole ascetic acid (IAA), zeatin riboside (ZR), gibberellic acid (GA), and abscisic acid (ABA)], and the main sugars (glucose, fructose, sucrose, and sorbitol). The ZR content of Zaomeixiang pear was always greater than that of Korla fragrant pear at all stages. The ABA content was the opposite except for at 7 DAFB during cell division; the greatest difference was 30.87 ng/g, which appeared at 28 DAFB. ABA and ZR correlated negatively with cell number. After 7 DAFB, the ratio of IAA/ABA, ZR/ABA, and GA/ABA in Zaomeixiang pear was always greater than that for Korla fragrant pear at 28 DAFB. The difference in glucose content at 21 DAFB was the greatest, at 4.80 ng/g. Large amounts of sorbitol accumulated during whole-cell division. Glucose and sorbitol correlated positively with cell numbers. In summary, the data suggest that the different contents of glucose, sorbitol, ZR, and ABA, and the ratio of endogenous hormones might be related to cell division in Korla fragrant pear and Zaomeixiang pear. The result provides a theoretical basis for the large-size fruit’s high-quality production and genetic breeding of Korla fragrant pear and its bud mutation.

Physiological and biochemical changes during graft union formation in Carya illinoinensis

To reveal the physiological and biochemical mechanism underlying graft union formation in pecan (Carya illinoinensis), dynamic changes in content of nutrients, tannin, and phytohormones together with key enzyme activities were investigated 0, 3, 5, 7, 10, 14, 18, 22, 31, and 40 d after grafting (DAG), in homograft unions. During graft union formation, peroxidase (POD) activity increased at 7 - 10 DAG compared with that at 0 DAG. Polyphenol oxidase (PPO) activity was higher in grafted than ungrafted pecan seedlings (control) at 22 DAG, which was similar to POD activity. The tannin content exhibited a decreasing trend with grafting relative to the control. Indole-3-acetic acid (IAA) and zeatin riboside (ZR) content increased from 7 - 10 DAG, with higher average content than in the control at 14 - 31 DAG. Abscisic acid (ABA), soluble sugar, starch, and soluble protein content was generally lower in grafted plants than in the control. Combined with our previous anatomical observations, these results suggested that, during graft development, some enzymes and growth promoting hormones might be required for callus proliferation at early stage and for vascular reconnection at the later stage. Nutrients provided energy for the whole graft development process. In contrast, some polyphenols and growth inhibiting hormones seemed to have negative effects on this process.

Characterization of microRNAs involved in asymbiotic germination of Bletilla striata (Orchidaceae) seeds

Orchids are distributed worldwide, and some species have considerable economic value. Orchid seeds are minute in size, simple in structure, and deficient in nutrient reserves. Asymbiotic seed germination is an important propagation strategy for orchids. MicroRNAs (miRNAs) play an essential role in seed germination. However, few studies have examined miRNAs involved in seed germination in orchids. Here, we conducted comparative small RNA sequencing at five stages to characterize the miRNAs involved in asymbiotic seed germination in Bletilla striata. A total of 253 known and 125 novel miRNAs were identified. Of them, 71 known and 29 novel miRNAs showed distinct expression among the five stages. Quantitative PCR revealed negative correlations of expression between differentially expressed miRNAs (DE miRNAs) and their targets. Function annotation and enrichment analyses of the targets of DE miRNAs between adjacent stages indicate that miRNA-target regulations are involved in many important processes during germination, such as signaling, biosynthesis, and transport of plant hormones. Twenty-two miRNAs were inferred to participate in plant hormone-related processes. The contents of abscisic acid, gibberellin A3, indole-3-acetic acid, jasmonic acid, trans zeatin riboside, and N6-(Δ2-isopentenyl) adenine varied significantly among the five stages. Nine tested plant hormone-related miRNAs and their targets exhibited significant correlations with at least one plant hormone. 5′-RLM-RACE validated that a transcript encoding auxin response factor was cleaved by Bst-miR160e as predicted. For the first time, we characterized miRNAs associated with the asymbiotic seed germination of an orchid species, which will help understand the miRNA-mediated regulatory mechanism of seed germination in orchids.

Effects of exogenous methyl-jasmonate on the morphology, hormone status, and gene expression of developing lateral roots in Malus hupehensis

Malus hupehensis is regarded as a superior rootstock in China. In this study, in order to investigate the mechanism by which MeJA promotes and affects lateral root (LR) development, M. hupehensis seedlings were treated with exogenous applications of 1 μM methyl-jasmonate (MeJA). Results indicated that MeJA treatment promoted LR development, but inhibited shoot development. MeJA treatment increased the levels of both endogenous auxin (IAA) and zeatin-riboside (ZR), and reduced gibberellin (GA1+3). Additionally, a significant upregulation in the expression of MdCOI1, MdMYC2 and MdJDL1 were also observed in response to the MeJA treatment. Although transcript levels of key IAA synthesis related genes increased, but those genes related to IAA transport were declined, which corresponded with higher IAA levels in the MeJA-treated samples. The expression of MdIAA5, which is a negative regulator of MdARF7, was dramatically downregulated in MeJA-treated apple seedlings, resulted in elevated expression of MdLBD16 and MdLBD29. Additionally, the expression of MdCYCD3;1 and MdCYCP4;1 were induced, which in turn increased LR development. Collectively, MeJA treatment increased the number of LRs and other growth characteristics.

Protocol development for somatic embryogenesis, SSR markers and genetic modification of Stipagrostis pennata (Trin.) De Winter

BackgroundStipagrostis pennata (Trin.) De Winter is an important species for fixing sand in shifting and semi-fixed sandy lands, for grazing, and potentially as a source of lignocellulose fibres for pulp and paper industry. The seeds have low viability, which limits uses for revegetation. Somatic embryogenesis offers an alternative method for obtaining large numbers of plants from limited seed sources.ResultsA protocol for plant regeneration from somatic embryos of S. pennata was developed. Somatic embryogenesis was induced on Murashige & Skoog (MS) medium supplemented with 3 mg·L–1 2,4-D subsequently shoots were induced on MS medium and supplemented with 5 mg·L–1 zeatin riboside. The highest shoots induction was obtained when embryogenic callus derived from mature embryos (96%) in combination with MS filter-sterilized medium was used from Khuzestan location. The genetic stability of regenerated plants was analysed using ten simple sequence repeats (SSR) markers from S. pennata which showed no somaclonal variation in regenerated plants from somatic embryos of S. pennata. The regenerated plants of S. pennata showed genetic stability without any somaclonal variation for the four pairs of primers that gave the expected amplicon sizes. This data seems very reliable as three of the PCR products belonged to the coding region of the genome.Furthermore, stable expression of GUS was obtained after Agrobacterium-mediated transformation using a super binary vector carried by a bacterial strain LBA4404.ConclusionTo our knowledge, the current work is the first attempt to develop an in vitro protocol for somatic embryogenesis including the SSR marker analyses of regenerated plants, and Agrobacterium-mediated transformation of S. pennata that can be used for its large-scale production for commercial purposes.

Absorption of Carbon-13 Labelled Fullerene (C60) on Rice Seedlings and Effect of Phytohormones on Growth

This study explores the effects of nanomaterials in rice seedlings using carbon 13 (13C)-labelled fullerene (C60). The experiment consisted of three groups, one CK and two nano particle groups with C60: 100 mg L-1 and 20 mg L-1. Mass spectrometry indicated higher 13C abundances in the nano particle groups compared with the CK. The 13C abundances of the 20 mg L-1 group, 100 mg L-1 group and CK were 1.0718%, 1.0715% and 1.0704%, respectively. We analyzed phytohormone concentrations in the rice at harvest time. Decreases in the concentrations of dihydrozeatin riboside (23% and 18% for the 20 mg L-1 and 100 mg L-1 group, respectively), zeatin riboside (23% and 18%, respectively), abscisic acid (11.1% and 12.7%, respectively), brassinolide (12.9% and 13.1%, respectively) and gibberellic acid 4 (12.9% and 13.1%, respectively) were observed compared with the CK. The gibberellic acid 3 concentrations in the 20 mg L-1 and 100 mg L-1 group increased by 12% and 7% compared with the CK, respectively. The methyl jasmonate concentration in the 100 mg L-1 group increased by 19.4% compared with the CK. The concentration of indole-3-acetic acid in the 100 mg L-1 group decreased by 13.5% compared with the CK. There was no change on isopentenyl adenosine concentration. This study indicates that C60 can be absorbed by rice and its effect on the growth of rice via phytohormones, including ABA, IAA, IPA, BR, GA₃, GA₄, DHZR, ZR and JA-ME. The results showed that, under the treatments of C60 NMs, the contents of some phytohormone in rice were decreased in comparison with CK.

Different Plant Growth Regulators on Improvement of Potato (Solanum tuberosum L.)

The study compared the effects of MS medium containing 0.1 mg L-1 gibberellic acid (GA3) and α-naphthaleneacetic acid (NAA) in combination with 2.0 mg L-1 of kinetin (KIN), 2.0 mg L-1 of benzyl aminopurine (BAP), 1.0 mg L-1 of zeatine riboside (ZR), and 0.5 mg L-1 of jasmonic acid (JA) for the micropropagation development of three potato (Solanum tuberosum L.) cultivars namely Caspar, Granola and Pasinler-92 using binodal stem explants. The results of this research clearly indicated that inclusion of JA among the other plant growth regulators significantly increased shoot regeneration and other characteristics of all potato cultivars used in the study. The minimum days to shoot proliferation on three cultivars ranged 4.0–5.5 d (best result on cv. Pasinler-92) on MS medium containing 0.5 mg L-1 JA. The minimum time to root initiation (11.0 d) was observed on cv. Pasinler-92 on the same medium. The maximum number of axillary shoots (15.25) and nodes (19.0), maximum shoot length (17.25 cm), leaves (19.0) and roots (25.25) were noted on cv. Caspar. The longest roots (18.45 cm) on cv. Pasinler-92, and the maximum fresh weight (404.87 mg) and dry weight (61.85 mg) of plantlets from cv. Granola were also recorded on MS medium fortified with 0.1 mg L-1 GA3+0.1 mg L-1 NAA+0.5 mg L-1 JA.

Endophytic Strain Bacillus subtilis 26D Increases Levels of Phytohormones and Repairs Growth of Potato Plants after Colorado Potato Beetle Damage.

Plant damage caused by defoliating insects has a long-term negative effect on plant growth and productivity. Consequently, the restoration of plant growth after exposure to pathogens or pests is the main indicator of the effectiveness of the implemented defense reactions. A short-term Leptinotarsa decemlineata Say attack on potato tube-grown plantlets (Solanum tuberosum L.) led to a reduction of both the length and mass of the shoots in 9 days. The decrease of the content of phytohormones—indole-3-acetic acid (IAA), abscisic acid (ABA), zeatin and zeatin–riboside—in shoots of damaged potato plants was found. Endophytic strain Bacillus subtilis 26D (Cohn) is capable of secreting up to 83.6 ng/mL IAA and up to 150 ng/mL cytokinins into the culture medium. Inoculation of potato plants with cells of the B. subtilis 26D increases zeatin–riboside content in shoots and the mass of roots of undamaged plants, but does not influence content of IAA and ABA and growth of shoots. The presence of B. subtilis 26D in plant tissues promoted a rapid recovery of the growth rates of shoots, as well as the wet and dry mass of roots of plants after the pest attack, which we associate with the maintenance of a high level of IAA, ABA and cytokinins in their tissues.

Dynamic Changes in Endogenous Hormones in Terminal Buds from Different Crown Positions in Sequoia sempervirens (Lamb.) Endl

Endogenous hormones can improve plant resistance and regulate growth and development. To obtain the basis of chemical control technology for improving Sequoia sempervirens resistance in Xuzhou, China, the current study probed the dynamic changes of endogenous hormones in terminal buds from different crown positions in S. sempervirens. Enzyme-linked immunosorbent assay (ELISA) was used to measure changes in the contents of endogenous hormones in terminal buds from the upper, middle, and lower lateral branches. The results were as follows: Indole acetic acid (IAA) in all terminal positions had a similar change trend of “rise–drop–rise.” Gibberellic acid (GA) in the upper and middle terminal buds showed similar trends of “drop–rise,” but GA in the lower lateral branches presented a “rise–drop” trend. Zeatin–riboside (ZR) in all terminal positions had similar change trends of “drop–rise.” Abscisic acid (ABA) in all terminal positions had similar change trends of “drop–rise–drop.” the trend of (IAA + GA + ZR)/ABA in all terminal positions was the same as that of IAA. Our results confirmed that, in autumn, the high content and ratio of stimulatory endogenous hormones in the terminal bud of S. sempervirens induced the terminal bud cells to continue to divide and grow, and the new branches could not be fully lignified and deeply dormant before the onset of low temperatures in winter, which led to a decrease in cold resistance and even the death of the terminal buds.

Peroxidase Enzyme Fractions as Markers of Somatic Embryogenesis Capacities in Olive (Olea europaea L.).

As part of the search for biochemical markers of somatic embryogenesis in tissue cultures of olive (Olea europaea L.), peroxidases (POXs) in both the soluble and ionically wall-bound fractions were studied in two reputed olive cultivars (cvs.): “Picholine Marocaine” and “Dahbia”. In order to carry out embryogenesis induction, proximal cotyledons were cultured in modified olive medium (OMc) supplemented with 25 μM indole-3-butylic acid (IBA) and 2.5 μM 2-isopentenyladenine (2iP), while distal leaf fragments (somatic explants) were cultured in OMc supplemented with 4.56 µM zeatin riboside (ZR) and 10.25 µM 1-naphthaleneacetic acid (NAA). Regarding embryogenic potentials, the zygotic explants (cv. Picholine Marocaine: 43.39%; cv. Dahbia: 53.41%) were more regenerative than the somatic explants (cv. Picholine Marocaine: 13.05%; cv. Dahbia: 19.51%). The enzyme assay showed a higher POX activity in embryogenic calluses (ECs) than in nonembryogenic calluses (NECs) for the zygotic explants in both studied cultivars. When expressed as units per milligram of proteins (U mg−1 proteins), the highest total POXs activities (soluble POXs + ionically wall-bound POXs) were found in the ECs derived from the zygotic explants; for cv. Dahbia, 65% of the enzyme activities came from the ionically wall-bound fractions. Polyacrylamide gel electrophoresis showed that the ECs of the highly active cv. Dahbia were characterized by highly active isoperoxidases that were revealed in four migration zones, particularly a doublet in the A4 zone (Rf 0.70–0.73) present in the ionically wall-bound POXs. The fast-moving anodic POXs of the ionically wall-bound fractions could be adopted as an early electrophoretic test to determine the embryogenesis capacities in olive tissue culture materials. As biochemical markers, the POX enzyme and its profile in fractions, i.e., as soluble POXs and ionically wall-bound POXs, can offer a valuable tool for improving the tissue culture of olive via somatic embryogenesis.

Effects of NPK and ALA on endogenous hormones of Leymus chinensis (Trin.) Tzvel under drought stress

An experiment was conducted to elucidate the negative impacts of drought on growth and hormones of Leymus chinensis. Results showed that plant height, dry weight and zeatin riboside contents declined under drought condition over the control. Whereas indole acetic acid, gibberellic acid and abscisic acid contents were augmented under stress environment over the normal conditions. Exogenous application of NPK and/or 5-aminolevulinic acid (ALA) depicted more pronouncing response to alleviate adversities of drought. Conclusively, foliar application of 'Urea (1%) + KH2PO4 (1%) + ALA (50 mg/l)' produced better results under drought stress on the evaluated parameters.

Growth and physiological responses of cotton plants to salt stress

AbstractThe objective of this study was to investigate the growth and physiological responses cotton plants to salt stress. At seven leaf stage, cotton plants were subjected to two treatments; 0 mM NaCl as the control and 150 mM NaCl as the salt stress treatment, respectively. The effect of salt stress on leaf gas exchange rates, leaf nitrogen concentration, chlorophyll content, leaf K+ and Na+ concentrations, plant water status, endogenous phytohormone concentrations, dry matter accumulation and partitioning in plant organs was evaluated. The results showed that salt stress significantly decreased plant growth, water consumption, leaf water relations characteristics and leaf gas exchange rates as compared to the control. Under salt, photosynthetic rate was reduced to less extend than did stomatal conductance (gs) and transpiration rate, resulting in greater intrinsic and instantaneous water use efficiencies compared to the control plants. gs decreased linearly with decreasing leaf water potential and leaf hydraulic conductance under salt. Salt‐stressed plants possessed a significant higher concentration of abscisic acid ([ABA]leaf), while a significantly lower concentrations of gibberellic acid ([GA3]leaf) and zeatin riboside ([ZR]leaf) in leaf than those grown under control. Negative linear relationships were found between gs and [ABA]leaf, ratio of [ABA]leaf to [GA3]leaf, ratio of [ABA]leaf to ([GA3]leaf+[ZR]leaf), respectively. Salt stress significantly decreased leaf K+ concentration, the ratio of K+/Na+ in leaf, shoot growth and biomass partitioning into leaf and stem, whereas increased leaf chlorophyll content, leaf nitrogen concentration and biomass partitioning into boll. Although the water use efficiency of plant biomass was unaffected, the water use efficiency of boll biomass was significantly enhanced by salt stress. Collectively, salt‐induced changes in both hydraulic and chemical properties were involved in mediating the leaf gas exchange response to salt stress, and the enhanced leaf nitrogen concentration and biomass partitioning into boll may lead to a sustained yield with less water consumption in cotton plants grown under moderate salinity stress.

Alternative fertilizer and irrigation practices improve rice yield and resource use efficiency by regulating source-sink relationships

Abstract Understanding the inherent characteristics based on leaf and root source and grain sink under an improved cultivation practice is important to achieve both high grain yield and resource use efficiency in paddy rice. A field experiment to investigate the characteristics was conducted across two years using Wuyunjing24 with five cultivation practices including no nitrogen (N) application (0 N), local farmers' practice (LFP), and three improved cultivation practices (ICPs) consisting of improved fertilizer N practice and higher plant density (ICP1), the same practices as ICP1 but with alternate wetting and moderate drying (AWMD) rather than with the continuous flooding (CF) irrigation (ICP2), and the same practices as ICP2 but plus organic fertilizer application (ICP3). The results showed that all three ICPs could synchronously increase grain yield and resource use efficiency, and the increase was the most for ICP3 and followed by ICP2, when compared with LFP. The total number of spikelets, shoot and root biomasses, total leaf area index (LAI), effective LAI, grain weight-leaf ratio, specific leaf N content, and leaf photosynthetic rate, zeatin and zeatin riboside contents in panicles, leaves and roots, and the activities root of spikelets (the ratio of root activity to spikelet number) during grain filling were significantly increased with the improvement in cultivation practices. The results suggest that the improved cultivation practices are useful to achieve high yield and high resource use efficiency through improving source and sink characteristics and coordinating their relationships.

Humic acids‐based biostimulants impact on root viability and hormone metabolism in creeping bentgrass putting greens

AbstractCreeping bentgrass putting greens experience quality decline during summer due to heat and drought stress in U.S. transition zone and other areas with similar climate. Plant biostimulants have been used to improve turfgrass tolerance to abiotic stress. This study was designed to investigate the effect and modes of action of humic acid (HA) based biostimulants on turf quality, root viability, and hormone metabolism of creeping bentgrass during summer stress. The two humic acid formulations – solid powder and liquid, were characterized and applied at two rates of each formulation to a creeping bentgrass putting green from May through August in this study. Auxin indole‐3‐butyric acid (IBA) served as the positive control. Foliar application of either solid or liquid HA at 0.2% and 0.3% biweekly improved turf quality, photochemical efficiency and chlorophyll content at certain sampling dates. The HA treatments also increased leaf growth hormone cytokinin zeatin riboside (ZR) on July 25 and August 22 and auxin indole‐3‐acetic acid (IAA) on August 22. The HA treatments improved root length, surface area (SA), root volume, biomass, and viability. Solid HA (HA‐S) at 0.2%, 0.3% solution, liquid HA (HA‐L) at 0.2%, and 0.3% increased root viability by 91.8%, 122.4%, 57.1%, and 71.4%, respectively, when compared to the control. This study suggests foliar application of humic acid‐based biostimulants may be considered as an effective tool to improve turf performance in creeping bentgrass putting greens during summer months.

Integrated metabolic profiling and transcriptome analysis of pigment accumulation in Lonicera japonica flower petals during colour-transition

BackgroundPlants have remarkable diversity in petal colour through the biosynthesis and accumulation of various pigments. To better understand the mechanisms regulating petal pigmentation in Lonicera japonica, we used multiple approaches to investigate the changes in carotenoids, anthocyanins, endogenous hormones and gene expression dynamics during petal colour transitions, i.e., green bud petals (GB_Pe), white flower petals (WF_Pe) and yellow flower petals (YF_Pe).ResultsMetabolome analysis showed that YF_Pe contained a much higher content of carotenoids than GB_Pe and WF_Pe, with α-carotene, zeaxanthin, violaxanthin and γ-carotene identified as the major carotenoid compounds in YF_Pe. Comparative transcriptome analysis revealed that the key differentially expressed genes (DEGs) involved in carotenoid biosynthesis, such as phytoene synthase, phytoene desaturase and ζ-carotene desaturase, were significantly upregulated in YF_Pe. The results indicated that upregulated carotenoid concentrations and carotenoid biosynthesis-related genes predominantly promote colour transition. Meanwhile, two anthocyanins (pelargonidin and cyanidin) were significantly increased in YF_Pe, and the expression level of an anthocyanidin synthase gene was significantly upregulated, suggesting that anthocyanins may contribute to vivid yellow colour in YF_Pe. Furthermore, analyses of changes in indoleacetic acid, zeatin riboside, gibberellic acid, brassinosteroid (BR), methyl jasmonate and abscisic acid (ABA) levels indicated that colour transitions are regulated by endogenous hormones. The DEGs involved in the auxin, cytokinin, gibberellin, BR, jasmonic acid and ABA signalling pathways were enriched and associated with petal colour transitions.ConclusionOur results provide global insight into the pigment accumulation and the regulatory mechanisms underlying petal colour transitions during the flower development process in L. japonica.

Melatonin improves the seed filling rate and endogenous hormonal mechanism in grains of summer maize.

The unpredictable precipitation and water deficit conditions in semiarid regions significantly reduce the yield of summer maize. The exogenous application of plant growth regulators can be used as a strategy to enhance plant stress tolerance and improve the growth and yield of maize under semiarid conditions. Here, we studied the protective role of melatonin application on maize yield using grain filling rate and hormonal crosstalk in maize grains. In the first field experiment, seeds were soaked with melatonin at a concentration of 0 (SM0 ), 25 (SM1 ), 50 (SM2 ), and 75 μM (SM3 ) μM. In contrast, in the second experiment, melatonin was applied on the foliage at the ninth leaf stage at a concentration of 0 (FM0 ), 25 (FM1 ), 50 (FM2 ), and 75 (FM3 ) μM. Our findings showed that melatonin treatments as seed soaking significantly increased single seed weight, seed filling rate in superior, medium and inferior seeds by regulating the hormone levels compared to foliar application. Application of melatonin significantly increased the zeatin+zeatin riboside (Z+ZR), indole-3-acetic acid (IAA), and gibberellic acid (GA) contents. However, it significantly inhibited the contents of abscisic acid (ABA) during the seed filling period. The content of Z+ZR, IAA, and GA was positively correlated with the maximum seed filling rate, seed weight, and mean filling rate in middle, superior and lower seeds, while the ABA was negatively correlated. The ABA content in inferior seeds was positively correlated with the maximum and mean seed filling rate. In semiarid regions, melatonin treatment of SM2 and FM2 significantly increased the dry matter per plant, 100-grain weight, seed filling rate, IAA, Z+ZR, GA contents, ear characteristics, and maize yield.

Transcriptome Analysis Reveals the Symbiotic Mechanism of Ustilago esculenta-Induced Gall Formation of Zizania latifolia.

Zizania latifolia is a perennial aquatic vegetable, whose symbiosis with the fungus Ustilago esculenta (member of Basidiomycota, class Ustilaginaceae) results in the establishment of swollen gall formations. Here, we analyzed symbiotic relations of Z. latifolia and U. esculenta, using a triadimefon (TDF) treatment and transcriptome sequencing (RNA-seq). Specifically, accurately identify the whole growth cycle of Z. latifolia. Microstructure observations showed that the presence of U. esculenta could be clearly observed after gall formation but was absent after the TDF treatment. A total of 17,541 differentially expressed genes (DEGs) were identified, based on the transcriptome. According to gene ontology term and Kyoto Encyclopedia of Genes and Genomes pathway results, plant hormone signal transduction, and cell wall-loosening factors were all significantly enriched due to U. esculenta infecting Z. latifolia; relative expression levels of hormone-related genes were identified, of which downregulation of indole 3-acetic acid (IAA)-related DEGs was most pronounced in JB_D versus JB_B. The ultra-high performance liquid chromatography analysis revealed that IAA, zeatin+trans zeatin riboside, and gibberellin 3 were increased under U. esculenta infection. Based on our results, we proposed a hormone-cell wall loosening model to study the symbiotic mechanism of gall formation after U. esculenta infects Z. latifolia. Our study thus provides a new perspective for studying the physiological and molecular mechanisms of U. esculenta infection of Z. latifolia causing swollen gall formations as well as a theoretical basis for enhancing future yields of cultivated Z. latifolia.[Formula: see text] The author(s) have dedicated the work to the public domain under the Creative Commons CC0 "No Rights Reserved" license by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law. 2021.

РІВЕНЬ ГЛЮКОЗИ ТА ГАММА-ГЛУТАМІЛТРАНСПЕПТИДАЗНА АКТИВНІСТЬ У КЛІТИНАХ ГЕПАТОЦИТАРНОГО ПОХОДЖЕННЯ ЗА ДІЇ ЕКСТРАКТІВ ТА ЦИТОКІНІНОВИХ ФРАКЦІЙ ЛІКАРСЬКИХ ГРИБІВ

Mushroom extracts show the multifunctional activity and have a wide range of applications for the treatment of various diseases, including cancer. However, the full composition of the compounds that produce macromycetes that exhibit antitumor properties has not yet been established. Impaired glucose metabolism and activation of gamma-glutamyltranspeptidase (GGT) in tumor cells may be a key marker of biochemical anaplasia in neoplasms. The aim of the study was to investigate the effect of crude extracts and cytokinin fractions isolated from the mycelial biomass of medicinal mushrooms on the biological properties of cells of hepatocyte-like cells of the HepG2 line (human hepatocellular carcinoma). The objects of the research were pure mushroom cultures of Hericium coralloides, Fomitopsis officinalis, Trametes (Coriolus) versicolor, Pleurotus ostreatus and Morchella esculenta. Cytokinin fractions from the extracts were isolated by centrifugation followed by fractionation and purification using ion exchange chromatography. Qualitative and quantitative analysis of cytokinins was performed by high-performance liquid chromatography. GGT activity was determined using the kit "Filisit" (Ukraine), glucose level – glucose oxidase method, with modifications for the cellular culture medium. The analysis of mycelial biomass of medicinal macromycetes revealed the presence of transzeatin, zeatin riboside, zeatin-O-glucoside and isopentenyladenine, that showed high activity in relation to cytokinin synthesis. Inhibition of glucose diffusion from the cultivation medium with the use of crude extracts and cytokinin fractions of medicinal mushroom and a decrease in GGT activity, more pronounced with the action of cytokinin fractions, compared with crude extracts, was noted. The difference between the effects of crude extracts and cytokinin fractions indicated the complex nature of the action of biologically active substances of medicinal mushroom. Presented results regarding the effects of crude extracts and cytokinin fractions of medicinal mushroom showed a normalizing effect on the main metabolic parameters which change in tumor cells, as a mechanism of biochemical anaplasia.