Malus Hupehensis Research Articles

Nitrogen Levels Regulate Sugar Metabolism and Transport in the Shoot Tips of Crabapple Plants.

To comprehensively understand the responses of carbohydrate metabolism and transport to different levels of nitrogen supply in growing shoot tips of crabapple (Malus hupehensis Rehd), enzyme activities and related genes involved in the sugar metabolism pathway were investigated. The nitrogen and chlorophyll content of plants increased with increasing nitrogen supply. High nitrogen application increased the net photosynthesis rate and the growth rate of shoot tips but decreased the synthesis capability of sucrose and sorbitol in mature leaves. However, the shoot tips of plants under high-nitrogen treatment had higher contents of sucrose and sorbitol than did those under low-nitrogen treatment, while the activity of sucrose phosphate synthase and aldose-6-phosphate was increased and the transporters MdSOT and MdSUT were up-regulated. Moreover, the activities of enzymes involved in sucrose and hexose metabolism (including sucrose synthase, fructokinase, and hexokinase) were enhanced in the shoot tips of plants under high-nitrogen conditions, and the expression levels of MdSUSY3 and MdHK1 were significantly up-regulated. These findings indicate that a high nitrogen supply increases the metabolic capacity of assimilatory substances in shoot tips, accelerates the efficiency of sugar utilization and eventually leads to a rapid increase in the growth of shoot tips. Our results highlight that high nitrogen increases the capacity of sugar unloading and metabolic utilization in growing shoot tissues.

Rapid enrichment and separation of two novel minor phenols from Malus hupehensis utilizing liquid-liquid extraction with three-phase solvent system and high-speed counter-current chromatography based on the polarity parameter.

For a rapid enrichment and separation of minor components from Malus hupehensis, the selection of suitable solvent system is the great challenge for liquid-liquid extraction with a three-phase solvent system and high-speed counter-current chromatography. According to the concept of "like dissolves like," the similarity of the average polarity between solvent system and target compounds was the significant characteristic of liquid-liquid extraction with a three-phase solvent system and high-speed counter-current chromatography separation. The polarity parameter model provides a way to calculate the polarity of unknown compounds. Under the guidance of the polarity, an efficient enrichment and separation approach was established through liquid-liquid extraction and high-speed counter-current chromatography with solvent systems composed of n-hexane-ethyl acetate-acetonitrile-water (5:3:5:7, v/v), n-hexane-ethyl acetate-methanol-water (1:2:1:2, v/v), respectively. Thus, the total content of minor compounds was increased from 2.6% to 17.2%, and two novel compounds (6´´-O-coumaroyl-2´-O-glucopyranosylphloretin and 3´´´-methoxy-6´´-O-feruloy-2´-glucopyranosylphloretin) were obtained. The discovery of the new dihydrochalcones expanded the structural diversity of compounds produced by the genus Malus. The experimental results demonstrated that compound polarity can be described by the polarity parameter model and is an important reference for investigating optimum solvent systems for liquid-liquid extraction with a three-phase solvent system and high-speed counter-current chromatography.

Extraction and separation of flavonoids from Malus hupehensis using high-speed countercurrent chromatography based on deep eutectic solvent

In the present experiment, a green and highly efficient extraction method for flavonoids established on deep eutectic solvents (DESs) was investigated by using the response surface methodology. The DES-based high-speed countercurrent chromatography (HSCCC) solvent systems were developed for the separation of high purity compounds from the DES extract of Malus hupehensis for the first time. Under the optimal conditions (liquid-to-solid ratio of 26.3 mL/g, water content of 25.5%, and extraction temperature of 77.5°C), the yield of flavonoids was 15.3 ± 0.1%, which was superior to that of the methanol extraction method. In accordance with the physical property of DES-based HSCCC solvent systems and K values of target compounds, DES-based HSCCC solvent systems composed of choline chloride/glucose-water-ethyl acetate (ChCl/Glu-H2O-EAC, 1:1:2, v/v) was selected for the HSCCC separation. Thus, five flavonoids (two novel compounds 1-2, 6´´-O-coumaroyl-2´-O-glucopyranosylphloretin and 3´´´-methoxy-6´´-O-feruloy-2´-O-glucopyranosylphloretin; three know compounds 3-5, namely, avicularin, phloridzin, and sieboldin) were efficiently separated from Malus hupehensis. DESs are the environment friendly and highly efficient solvents as the components of extraction solvent and HSCCC solvent system, and can be re-utilized many times. However, ethyl acetate can be soluble with a few hydrogen bond donors, such as urea, carboxylic acid and polyol, through the shake flask test. It is the great difficulty for the efficient and rapid separation of target compounds from the DESs extract because of the DESs residual in the HSCCC fractions. ChCl and Glu are the great choices of DESs without this problem. In addition, K values increased with the increase of the molar ratio of ChCl/Glu and the content of water, which could effectively guide us to choose the suitable DES-based HSCCC solvent system. The twice HSCCC separation results indicated that DES was the valuable and green solvent for the HSCCC separation of pure compounds from the extract for the first time, and showed the recycle superiority of DES-based HSCCC solvent system.

Ectopic expression of a Malus hupehensis Rehd. myo- inositol oxygenase gene (MhMIOX2) enhances tolerance to salt stress

Myo-inositol oxygenase (MIOX), an essential monooxygenase enzyme, catalyzes the conversion of myo-inositol (MI) into d-glucuronic acid (D-GlcUA). The MIOX genes have been isolated and studied extensively in model plants and crops, but the characteristics and roles of MIOXs in woody plants remain largely unknown. In this study, two MhMIOXs cloned from Malus hupehensis Rehd. were characterized. Both MhMIOX1 and MhMIOX2 expression were significantly induced throughout the whole ABA and NaCl stress treatment, especially under NaCl treatment. To gain insight into the roles of MhMIOX1/2 in MI metabolism, we heterologously expressed MhMIOX1/2 in poplar and Arabidopsis. The results showed that only MhMIOX2 overexpression caused the decrease of MI content in transgenic plants. Either the transgenic poplar or Arabidopsis lines overexpressing MhMIOX2 showed better growth performance than the wild type (WT) upon salt stress treatment. Furthermore, compared to the WT, the H2O2 and MDA content obviously decreased, and the activity of ROS-scavenging enzymes (POD, APX and CAT) was strongly elevated in transgenic poplar under salt stress conditions, which suggest MhMIOX2 overexpression enhancs the tolerance of the transgenic plants to salt stress. Besides, there was no obvious difference in ascorbate (AsA) content between the WT and transgenic poplar under normal condition, indicating MhMIOX2 is important for MI oxidative metabolism, but not for AsA production in poplar and Arabidopsis.

Study on A Chinese Medicine Chewable Tablet for Anti-Alcoholism and Liver Protection

In this study, the resources of traditional Chinese medicine were exploited reasonably, which was mainly composed of the active components of malus hupehensis and four kinds of plant components, such as Pueraria lobata, tangerine peel, jujube and corn sweet core. The preparation process of the product has been solved, and preliminary product efficacy experiments have been carried out, which has been proved to be able to relieve the symptoms of alcohol discomfort.

Exogenous Strigolactones alleviate KCl stress by regulating photosynthesis, ROS migration and ion transport in Malus hupehensis Rehd

AimsIn recent years, the application of large amounts of potash fertilizer in apple orchards leads to worsening KCl stress. Strigolactone (SL), as a novel phytohormone, reportedly participates in plant tolerance to NaCl and drought stresses. However, the underlying mechanism and the effects of exogenous SL on the KCl stress of apple seedlings remain unclear. MethodsWe sprayed different concentrations of exogenous SL on Malus hupehensis Rehd. under KCl stress and measured the physiological indexes like, photosynthetic parameter, content of ROS, osmolytes and mineral element. In addition, the expressions of KCl-responding genes and SL-signaling genes were also detected and analyzed. ResultsApplication of exogenous SL protected the chlorophyll and maintained the photosynthetic rate of apple seedlings under KCl stress. Exogenous SL strengthened the enzyme activities of peroxidase and catalase, thereby eliminating reactive oxygen species production induced by KCl stress, promoting the accumulation of proline, and maintaining osmotic balance. Exogenous SL expelled K+ outside of the cytoplasm and compartmentalized K+ into the vacuole, increased the contents of Na+, Mg2+, Fe2+, and Mn2+ in the cytoplasm to maintain the ion homeostasis under KCl stress. ConclusionsExogenous SL can regulate photosynthesis, ROS migration and ion transport in apple seedlings to alleviate KCl stress.

Transcriptome comparison among three types of annual roots of Malus hupehensis Rehd

Transcriptome comparison among three types of annual roots of <i>Malus hupehensis</i> Rehd

The mitigation effects of exogenous dopamine on low nitrogen stress in Malus hupehensis

Dopamine plays numerous physiological roles in plants. We explored its role in the regulation of growth, nutrient absorption, and response to nitrogen (N) deficiency in Malus hupehensis Rehd. Under low N condition, plant growth slowed, and the net photosynthetic rates, chlorophyll contents, and maximal quantum yield of PSII (Fv/Fm) decreased significantly. However, the application of 100 μmol L−1 exogenous dopamine significantly reduced the inhibition of low N stress on plant growth. In addition to modifying root system architecture under low N supply, exogenous dopamine also changed the uptake, transport, and distribution of N, P, and K. Furthermore, exogenous dopamine enhances the tolerance to low nitrogen stress by increasing the activity of enzymes (nitrate reductase, nitrite reductase, glutamic acid synthase and glutamine synthetase) involved in N metabolism. We also found that exogenous dopamine promoted the expression of ethylene signaling genes (ERF1, ERF2, EIL1, ERS2, ETR1, and EIN4) under low N stress. Therefore, we hypothesized that ethylene might be involved in dopamine response to low N stress in M. hupehensis. Our results suggest that exogenous dopamine can mitigate low N stress by regulating the absorption of mineral nutrients, possibly through the regulation of the ethylene signaling pathway.

Hydrogen sulfide ameliorates cadmium chloride injury in seedlings of Malus hupehensis by reducing influx and accumulation of cadmium in roots

Hydrogen sulfide ameliorates cadmium chloride injury in seedlings of <i>Malus hupehensis</i> by reducing influx and accumulation of cadmium in roots

Malus hupehensis leaves extract attenuates obesity, inflammation, and dyslipidemia by modulating lipid metabolism and oxidative stress in high‐fat diet‐induced obese mice

Malus hupehensis leaves (MHL) are used to make traditional Chinese tea. In this study, MHL extract was shown to improve metabolic disorders and inflammatory response in high-fat diet-induced obese mice. MHL extract could reduce body weight, and significantly alleviate liver damage and fat accumulation. MHL extract caused a decrease in the levels of ALT, AST, AKP, TC, TG, LDL-C, and an increase in the level of HDL-C. It also caused a decrease in inflammatory cytokines, including TNF-α, IFN-γ, IL-1β, IL-6, and an increase in the anti-inflammatory cytokine IL-10 and IL-4. MHL extract could upregulate mRNA expression of PPAR-α, LPL, CPT1, CYP7A1, SOD1, SOD2, CAT, GSH1, and GSH-Px and downregulate that of PPAR-γ and C/EBP-α in the liver of obese mice. In conclusion, our work represents the first study demonstrating that MHL extract possesses an anti-obesity effect and alleviates obesity-related symptoms, including dyslipidemia, chronic low-grade inflammatory, and liver damage. PRACTICAL APPLICATIONS: The research may contribute to the development and application of MHL as functional foods or dietary supplement to fight against obesity.

Effects of dazomet fumigation on growth, biological characteristics of Malus hupehensis seedlings and soil environment

In this study, we examined the effects of dazomet fumigation with different concentrations (0, 0.1, 0.2, 0.4 g·kg-1) on the microbial characteristics of continuous cropping soil and growth of Malus hupehensis seedling in greenhouse and open-field pot. The results showed that all the treatment of dazomet fumigation could promote the growth of M. hupehensis seedlings in continuous cropping soil, with 0.2 g·kg-1 treatment showing the strongest effect. Compared to the control, plant height, stem diameter, dry weight of M. hupehensis seedlings in 0.2 g·kg-1 dazomet fumigation were increased by 192.9% and 91.8%, 72.8% and 60.1%, 196.8% and 195.0%, 138.5% and 130.7%, respectively in greenhouse and open-field. The root related indices (root length, root area, root volume, root respiration rate) were significantly promoted. The activities of SOD, POD, CAT in roots were increased by 114.6% and 118.5%, 123.5% and 107.6%, 164.6% and 175.6% respectively compared with the control, whereas the content of malondialdehyde was significantly lowered. Soil bacterial content, fungal content, copy number of Fusarium oxysporum gene and soil enzyme activity were significantly decreased with the increasing dazomet concentrations. In conclusion, 0.2 g·kg-1 dazomet fumigation could increase the biomass of M. hupehensis seedlings in continuous cropping, improve soil environment, and effectively alleviate the continuous cropping obstacle. Therefore, 0.2 g ·kg-1 dazomet fumigation could be given priority during the reconstruction of old apple orchards.

H2S pretreatment mitigates the alkaline salt stress on Malus hupehensis roots by regulating Na+/K+ homeostasis and oxidative stress

Hydrogen sulfide (H2S) plays an important role in the plant salt stress response. The main component of salt stress is neutral salt (NaCl); NaHCO3 and Na2CO3 play a key role in soil alkaline due to the influence of pH. Malus hupehensis Rehd. var. pingyiensis Jiang (Pingyi Tiancha, PYTC) is a salt-sensitive apple rootstock. Seedlings of PYTC pretreated with NaHS (an H2S donor) were exposed to an alkaline salt solution, and then the plant growth, root architecture, oxidative damage, Na+/K+ homeostasis and gene expression of MhSOS1 and MhSKOR were investigated. The results showed that NaHS pretreatment increased the endogenous H2S content in seedlings, significantly alleviated the alkaline salt stress-induced growth inhibition and oxidative damage by inducing antioxidant enzymes activities, and sustained the root activity and root architecture of PYTC in the alkaline salt solution. NaHS pretreatment significantly decreased the root Na+ content and increased K+ content to maintain the homeostasis of Na+/K+, and effect the expression of MhSOS1 and MhSKOR at the transcription level in the presence of the alkaline salt. Our study reveals that application of H2S could mitigate the toxic effect of alkaline salt stress on Malus hupehensis seedlings, thus providing a foundation for improved plant tolerance to alkaline salt stress.

Myo-inositol mediates reactive oxygen species-induced programmed cell death via salicylic acid-dependent and ethylene-dependent pathways in apple

As a versatile compound, myo-inositol plays vital roles in plant biochemistry and physiology. We previously showed that exogenous application of myo-inositol had a positive role in salinity tolerance in Malus hupehensis Rehd. In this study, we used MdMIPS (the rate-limiting gene of myo-inositol biosynthesis) transgenic apple lines to gain new insights into the physiological role of myo-inositol in apple. Decreasing myo-inositol biosynthesis in apple lines by RNA silencing of MdMIPS1/2 led to extensive programmed cell death, which manifested as necrosis of both the leaves and roots and, ultimately, plant death. Necrosis was directly caused by the excessive accumulation of reactive oxygen species, which may be closely associated with the cell wall polysaccharide-mediated increase in salicylic acid and a compromised antioxidant system, and this process was enhanced by an increase in ethylene production. In addition, a high accumulation of sorbitol promoted necrosis. This synergetic interplay between salicylic acid and ethylene was further supported by the fact that increased myo-inositol accumulation significantly delayed leaf senescence in MdMIPS1-overexpressing apple lines. Taken together, our results indicated that apple myo-inositol regulates reactive oxygen species-induced programmed cell death through salicylic acid-dependent and ethylene-dependent pathways.

Exogenous 6-benzyladenine application affects root morphology by altering hormone status and gene expression of developing lateral roots in Malus hupehensis.

Malus hupehensis is an extensively used apple rootstock in China. In the current study, M. hupehensis seedlings were treated with exogenous 2.2µm 6-benzyladenine (6-BA) so as to investigate the mechanism by which 6-BA affects lateral root development. The results indicate that 6-BA treatment promotes elongation and thickening of both root and shoot in M. hupehensis, but reduces the number of lateral roots, as well as reducing the auxin level after 6-BA treatment. Moreover, MhAHK4, MhRR1 and MhRR2 were also significantly up-regulated in response to 6-BA treatment. Expression levels of auxin synthesis- and transport-related genes, such as MhYUCCA6, MhYUCCA10, MhPIN1 and MhPIN2, were down-regulated, which corresponds with lower auxin levels in the 6-BA-treated seedlings. A negative regulator of auxin, MhIAA3, was induced by 6-BA treatment, leading to reduced expression of MhARF7 and MhARF19 in 6-BA-treated seedlings. As a result, expression of MhWOX11, MhWOX5, MhLBD16 and MhLBD29 was blocked, which in turn inhibited lateral root initiation. In addition, a lower auxin level decreased expression of MhRR7 and MhRR15, which repressed expression of key transcription factors associated with root development, thus inhibiting lateral root development. In contrast, 6-BA treatment promoted secondary growth (thickening) of the root by inducing expression of MhCYCD3;1 and MhCYCD3;2. Collectively, the changes in hormone levels and gene expression resulted in a reduced number of lateral roots and thicker roots in 6-BA-treated plants.

Carbohydrate metabolism and transport in apple roots under nitrogen deficiency

Soluble sugars play important roles in plant development and stress response, and the nitrogen supply level can affect the among-organ distribution and metabolism of sugar in plants and, in turn, plant growth. To explore the adaptive response of apple root growth to nitrogen supply and its relationship with sugar metabolism, we used a hydroponic culture system to study how the nitrogen supply affects soluble sugar concentrations and sugar metabolism in apple roots. In hydroponic seedlings of Malus hupehensis, low nitrogen application caused rapid and vigorous proliferation of lateral roots, and the transcript levels of MdSOT1 and MdSUT3, which are involved in photoassimilate unloading in roots, were upregulated. The accumulation of sorbitol and sucrose in the fine roots was higher, and the activities of sucrose synthase, invertase and sorbitol dehydrogenase, which are involved in the degradation of sucrose and sorbitol, were significantly increased under a low nitrogen supply. Genes involved in sugar degradation, such as MdSDH1, MdSuSy5, and MdNINV3, play important roles in the efficient use of sorbitol and sucrose under nitrogen deficiency. Additionally, the activity of fructokinase and hexokinase, which are involved in hexose phosphorylation, and transcript levels of MdFRK2 and MdHK3 were significantly upregulated under nitrogen deficiency, and the hexose phosphate products F6P and G6P accumulated greatly in the roots. These results showed that the sugar metabolism capability and sink strength of the roots increased under low nitrogen, indicating that low nitrogen promotes the utilization of sugar in the roots to meet the demand for sugar under rapid root growth.

MdINT1 enhances apple salinity tolerance by regulating the antioxidant system, homeostasis of ions, and osmosis

Myo-inositol is a versatile compound and plays a vital role in plant growth and stress tolerance. Previously, we found that exogenous application of myo-inositol enhanced the salinity tolerance in Malus hupehensis Rehd. by enhancing myo-inositol metabolism. In this study, we found that the tonoplast-localized myo-inositol transporter 1 (MdINT1) was involved in myo-inositol accumulation and conferred salinity tolerance in apple. MdINT1 is characterized by the highest transcripts among the four apple INT-like genes and could be induced by salt stress at the transcriptional level. Also, it was shown that myo-inositol level was slightly decreased in the leaves of transgenic apple lines over-expressing MdINT1, but was significantly increased in the leaves and roots of MdINT1 silencing line. Interestingly, overexpression of MdINT1 enhanced salinity tolerance by promoting Na+ and K+ balance, antioxidant activity, and accumulation of osmoprotectants in transgenic apple lines. In contrast, under salinity conditions, the MdINT1-mediated protective roles in the antioxidant activity, homeostasis of ions and osmosis were compromised, which in turn increased the risk of salt intolerance in the MdINT1 silencing line.

MhNRAMP1 From Malus hupehensis Exacerbates Cell Death by Accelerating Cd Uptake in Tobacco and Apple Calli.

Excessive cadmium (Cd) damages plants by causing cell death. The present study discusses the function of natural resistance-associated macrophage protein (NRAMP) on cell death caused by Cd in Malus hupehensis. MhNRAMP1 was isolated from M. hupehensis roots, and its protein was located in the cell membrane as a transmembrane protein characterized by hydrophobicity. MhNRAMP1 expression in the roots was induced by Cd stress and calcium (Ca) deficiency. MhNRAMP1 overexpression increased Cd concentration in yeasts and enhanced their sensitivity to Cd. Phenotypic comparisons of plants under Cd stress revealed that the growth of transgenic tobacco and apple calli overexpressing MhNRAMP1 was worse than that of the wild type (WT). The Cd2+ influx of transgenic tobacco roots and apple calli was higher, and the recovery time of the Cd2+ influx to a stable state in transgenic apple calli was longer than that of the WT. Cd accumulation and the percentage of apoptotic cells in transgenic lines were higher. Correspondingly, the caspase-1-like and vacuolar processing enzyme (VPE) activities and MdVPEγ expression were higher in transgenic apple calli, but the expression levels of genes that inhibit cell death were lower than those in the WT under Cd stress. Moreover, the Cd translocation from the roots to leaves was increased after MhNRAMP1 overexpression, but the Cd translocation from the leaves to seeds was not affected. These results suggest that MhNRMAP1 exacerbated Cd-induced cell death, which was accomplished by mediating Cd2+ uptake and accumulation, as well as stimulating VPE.

The complete chloroplast genome sequence of Malus toringoides (Rosaceae)

Malus toringoides belongs to the subfamily Amygdaloideae of Rosaceae, which is an endemic species in China. It has significant ornamental, economic, and ecological value. Herein, we assembled the complete chloroplast genome of Malus toringoides using the next-generation sequencing technology. The total length of the complete chloroplast genome was 160,093 base pair (bp), consisting of one large single-copy (LSC) region with a sequence length of 88,177 bp, one small single-copy (SSC) region which sequence length is 19,194 bp, and a pair of inverted repeat regions (IRs, 26361 bp). Besides, the complete chloroplast genome contained 128 genes, namely 83 protein-coding genes (PCGs), 37 tRNA genes (tRNA), and 8 rRNAgenes (rRNA), the GC content was 36.6%. The phylogenetic relationship among species in genus Malus is closely related, especially the phylogenetic relationship among Malus angustifolia, Malus prattii, Malus micromalus, Malus prunifolia, Malus baccata, Malus hupehensis and Malus toringoides. Furthermore, phylogenetic relationship of Malus toringoides in Malus was closely related to Malus hupehensis. Our study affords important genetic information for further researches on the related species.

Characterization of the complete chloroplast genome sequence of Malus toringoides (Rosaceae)

Malus toringoides belongs to the Malus genus (Rosaceae) and is a precious resource among wild plants. In this study, we report the first complete chloroplast (cp) genome sequence of M. toringoides. The whole cp genome contains 126 genes, 83 protein-coding genes, 35 tRNA genes, and eight rRNA genes. A maximum-likelihood phylogenetic tree analysis based on 12 complete chloroplast genomes indicated that M. toringoides clustered closely with Malus hupehensis. Thus, the chloroplast genome can provide valuable genetic information for the protection and exploitation of M. toringoides.

The complete chloroplast genome sequence of Malus halliana (Rosaceae), an important ornamental plant

Malus halliana is an important ornamental plant resource. Herein, we determined the complete chloroplast (cp) genome sequence of M. halliana using Illumina sequencing data. The whole cp genome is 160,089 bp in size, consisting of a pair of inverted repeats (IR 52,706 bp), a large single-copy region (LSC 88,189 bp), and a small single-copy region (SSC 19,194 bp). The plastid genome contains 129 genes, 84 protein-coding genes, 37 tRNA genes, and eight rRNA genes. In addition, a maximum-likelihood phylogenetic analysis demonstrated that M. halliana was most closely related to Malus hupehensis. The complete plastome sequence will provide useful genetic information for phylogenetic studies, the resolution of taxonomic discrepancies, and molecular breeding.