Myrica Rubra Research Articles

Wax bayberry is a suitable rootstock for Chinese red bayberry cultivated in saline-alkali soil

Wax bayberry or wax myrtle, Morella cerifera L., (MC) is a member of the Myricaceae family and belongs to the same genus as Chinese red bayberry (Morella rubra) (MR). It is an evergreen shrub native to Pennsylvania, USA, and is resistant to saline-alkali stress. China has a large area of saline-alkali soil in the south-eastern coastal regions, and this study aimed to evaluate the suitability of MR cv ‘Biqi’ grafting on MC for cultivation on saline soil. This MC rootstock tolerated stress in soil with high sodium, magnesium and calcium concentrations with no toxicity symptoms. Trees of cv ‘Biqi’ grafted on MC grew normally in saline-alkali soil, with dark green leaves, high chlorophyll content and healthy appearance, while the trees grafted on MR suffered severe chlorosis in saline alkali soil. The average fruit weight of the ‘Biqi’ cultivar grafted on MC in saline alkali soil steadily increased over the 2016–2018 period, and were larger in size and higher in sucrose and citric acid content than those on the MR rootstock grown in either coastal or mountainous areas. The bayberry grafted on MC rootstock also tended to flower and set fruit 1–2 years earlier than that grafted on MR rootstock. High compatibility between the scion (MR) and rootstock (MC) was observed in the microscopic section of the grafting interface. Thus, wax bayberry was considered an effective rootstock for the cultivation of red bayberry in saline-alkali soils.

First Report of Bayberry Leaf Blight Caused by Pestalotiopsis kenyana in Zhejiang Province, China.

Weizhi Xun and Changwang Wu contributed equally to this work In October 2020, bayberry (Myrica rubra (Lour.) S. et Zucc.) leaves that beginning to wither were collected in Wencheng County (N27°50', E120°03'). In the county, 4,120 ha of bayberry were planted, of which 58% were affected by the disease, and the severity of leaf disease per plant was 5 to25%. Bayberry leaves leaves were intensely green at first, then gradually turned yellow and brown,and completely withered. The leaves did not fall off at the beginning of the symptoms, but did fall after 1 to 2 months. To identify the pathogen, 50 diseased leaves with typical symptoms were collected from 10 diseased trees. Leaves with necrotic-tissue were firstly washed with sterilized water, and then tissue at the disease-/ healthy-tissuejunction removed with sterile surgical scissors. The tissues were soaked in 75% ethanol for 30 s, followed by 5% sodium hypochlorite solution for 3 to 4 min, rinsed with sterilized water 4 times, and placed on sterilized filter paper. The tissue was placed on PDA medium and cultured in an incubator at 25℃ (Nouri et al. 2019). After the colonies grew around the tissue, mycelia with the same morphology was selected and placed on fresh PDA. A pure culture of the pathogen was obtained after repeating the last process several times. The isolatedcolonies were white, with a round edge and a light-yellow back. Conidia were straight or slightly curved, with 3 to 4 septations. The internal transcribed spacer (ITS) regin translation elongation factor 1-α gene (TEF1-α), and beta-tubulin gene (β-TUB)(Chaiwan et al. 2020; Li et al. 2021; Chen et al. 2020; Chen et al. 2018) of the two strains were amplified and sequenced, and the sequences were uploaded to Gen bank (GenBank accession number.ACCC 35162: ITS OP891011, TEF1-α OP903533, β-TUB OP903531; ACCC 35163: ITS OP891012, β-TUB OP903534, TEF1-α OP903532). BLAST alignment indicated that the ITS sequence of strain ACCC 35162 had 100% identity with NR_147549.1, the TEF sequence had 100% identity with MT552449.1, and the TUB sequence had 99.87% identity with KX895323.1; the ITS sequence of strain ACCC 35163 had 100% identity with NR_147549.1, the TEF sequence had 100% identity with MT552449.1, and the TUB sequence had 99.86% identity with KX895323.1. A Phylogenetic tree using maximum likelihood/rapid bootstrapping run on XSEDE based on the above three sequences inferred that the two strains were identical to P. kenyana (Miller et al. 2010). The strain was preserved in the Agricultural Culture Collection of China (Preservation numbers: ACCC 35162, ACCC 35163). Following Koch's rule, six healthy plants leaves were inoculated with conidial suspensions (106 conidia mL-1) and mycelial plugs (5 mm)，and then placed in an artificial climate chamber (25℃, 90% humidity, 16-h light), sterile PDA and sterile water were used as blank controls. The same treatment was applied to fresh bayberry leaves under laboratory conditions, and brown spots were observed after three days. There were no symptoms in the control group. The experimental symptoms were similar to those in the field. Using the previous method, the same fungus was reisolated from the diseased leaves and again identified as P. kenyana. As far as we know, this is the first report causing disease on P. kenyana infecting bayberry in China, this disease seriously affected the yield and quality of bayberry and caused economic losses to farmers.

Tolerance and Acclimation of the Leaves of Nine Urban Tree Species to High Temperatures

To prepare and manage urban greenspace for a hotter future, we must select trees that can tolerate or acclimate to high temperatures. Here, we compared tolerance and acclimation to high temperatures among nine urban tree species in Japan. Saplings were exposed to heat from different times (early and mid-summer) during the growing season in a greenhouse. With the exception of Ginko, heating in early summer did not affect whole-tree health, suggesting that most urban tree species may be able to acclimate to higher temperatures during the early growing season. However, continued exposure to higher temperatures, as well as heating from mid-summer, had negative effects on tree health, leading to wilting/browning, especially for evergreen broadleaved species whose leaves mature slowly. Cornus florida, Styrax japonicus and Morella rubra were the most vulnerable to heating, such that all heated saplings had died by the end of summer. At the leaf level, leaf maturation of the deciduous species and Morella was negatively affected by heating, whereas that of Eurya emarginata and Euonymus japonicas were not affected. These two species also showed heat tolerance, having a higher T50 (temperature where leaf quantum yield declined to 50% of maximum value due to heat stress) compared to other species, as well as heat acclimation, where T50 was higher for the heated saplings compared to the control. Our results indicate that, while some species that cannot recover from heat damage in early summer could die, others can acclimate to sustained high temperatures, as well as to late summer heat. As heatwaves are expected to become more frequent and severe due to global warming, tree species need to be screened individually to assess their ability to tolerate or acclimate to high temperature.

Effect of proanthocyanidins from different sources on the digestibility, physicochemical properties and structure of gelatinized maize starch

The effect of proanthocyanidins (PAs) from Chinese bayberry leaves (BLPs), grape seeds (GSPs), peanut skins (PSPs) and pine barks (PBPs) on physicochemical properties, structure and in-vitro digestibility of gelatinized maize starch was investigated. The results showed that all PAs remarkably retarded starch digestibility, meanwhile, BLPs highlighted superiority in increasing resistant starch content from 31.29 ± 1.12 % to 68.61 ± 1.15 %. The iodine-binding affinity analysis confirmed the interaction between PAs and starch, especially the stronger binding of BLPs to amylose, which was driven by non-covalent bonds supported by XRD and FT-IR analysis. Further, we found that PAs altered the rheological properties, thermal properties and morphology structure of starch. In brief, PAs induced larger consistency, poorer flow ability, lower gelatinization temperatures and melting enthalpy change (ΔH) of starch paste. SEM and CLSM observation demonstrated that PAs facilitated starch aggregation. Our results indicated that PAs especially BLPs could be considered as potential additives to modify starch in food industry.

Involvement of a MYB Transcription Factor in Anthocyanin Biosynthesis during Chinese Bayberry (Morella rubra) Fruit Ripening.

Anthocyanin is a class of water-soluble flavonoids found in Chinese bayberry (Morella rubra) that is not only responsible for the variety of colors visible in nature but also has numerous health-promoting benefits in humans. Through comparative transcriptomics, we isolated and identified a transcription factor (TF) of the R2R3-MYB type, MrMYB9, in order to explore the anthocyanin biosynthesis pathway in red and white Chinese bayberries. MrMYB9 transcript was positively correlated with anthocyanin level and anthocyanin biosynthetic gene expression during Chinese bayberry fruit maturation (R-values in the range 0.54-0.84, p < 0.05). Sequence analysis revealed that MrMYB9 shared a similar R2R3 domain with MYB activators of anthocyanin biosynthesis in other plants. MrMYB9 substantially transactivated promoters of anthocyanin biosynthesis-related EBGs (MrCHI, MrF3'H, and MrANS) and LBGs (MrUFGT) upon co-expression of the AtEGL3 gene. Our findings indicated that MrMYB9 may positively modulate anthocyanin accumulation in Chinese bayberry.

Synergistic actions of three MYB transcription factors underpins the high accumulation of myricetin in Morella rubra.

Flavonols are health-promoting bioactive compounds important for human nutrition, health, and plant defense. The transcriptional regulation of kaempferol and quercetin biosynthesis has been studied extensively, while little is known about the regulatory mechanisms underlying myricetin biosynthesis, which has strong antioxidant, anticancer, antidiabetic, and anti-inflammatory activities. In this study, the flavonol-specific MrMYB12 in Morella rubra preferred activating the promoter of flavonol synthase 2 (MrFLS2) (6.4-fold) rather than MrFLS1 (1.4-fold) and upregulated quercetin biosynthesis. Furthermore, two SG44 R2R3-MYB members, MrMYB5 and MrMYB5L, were identified by yeast one-hybrid library screening using the promoter of flavonoid 3',5'-hydroxylase (MrF3'5'H), and transcript levels of these R2R3-MYBs were correlated with accumulation of myricetin derivatives during leaf development. Dual-luciferase and electrophoretic mobility shift assays demonstrated that both MrMYB5 and MrMYB5L could bind directly to MYB recognition sequence elements in promoters of MrF3'5'H or MrFLS1 and activate their expression. Protein-protein interactions of MrMYB5 or MrMYB5L with MrbHLH2 were confirmed by yeast two-hybrid and bimolecular fluorescence complementation assays. MrMYB5L-MrbHLH2 showed much higher synergistic activation of MrF3'5'H or MrFLS1 promoters than MrMYB5-MrbHLH2. Studies with Arabidopsis thaliana homologs AtMYB5 and AtTT8 indicated that similar synergistic regulatory effects occur with promoters of MrF3'5'H or MrFLS1. Transient overexpression of MrMYB5L-MrbHLH2 in Nicotiana benthamiana induced a higher accumulation of myricetin derivatives (57.70 μg g-1 FW) than MrMYB5-MrbHLH2 (7.43 μg g-1 FW) when MrMYB12 was coexpressed with them. This study reveals a novel transcriptional mechanism regulating myricetin biosynthesis with the potential use for future metabolic engineering of health-promoting flavonols.

Protective Effect of Chinese Bayberry (Myrica rubra Sieb. et Zucc.) Pomace Wine on Oxidative Stress of Hydrogen Peroxide by Regulating Keap1/Nrf2 Pathway in HepG2 Cells.

Chinese bayberry (Myrica rubra Sieb. et Zucc.) pomace wine (CPW) is fruity and rich in bioactive compounds, with high nutritional value and antioxidant activities. This study aims to investigate the protective effect of CPW on the oxidative damage induced by hydrogen peroxide in human hepatocellular carcinoma (HepG2) cells and CPW's possible underlying mechanism. The fluorescence assay results revealed that CPW pre-treatment inhibited intracellular reactive oxygen species (ROS) accumulation in H2O2-induced HepG2 cells and cell membrane injury. Meanwhile, CPW remarkably enhanced the activity of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), and the content of glutathione (GSH). Moreover, CPW pretreatment significantly regulated the expression of Kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid 2-related factor 2 (Nrf2) pathway-associated genes (Keap1, Nrf2, NADPH quinone oxidoreductase I (NQO1), and heme oxygenase-1 (HO-1)) and its downstream antioxidant genes (SOD, CAT, GSH, and the glutamate-cysteine ligase catalytic (GCLC) subunit) in HepG2 cells. These data demonstrated that CPW prevented H2O2-induced oxidative stress by regulating the Keap1/Nrf2 signaling pathway.

Complete genome sequence analysis of a novel citlodavirus isolated from the leaves of Myrica rubra in Yunnan.

Through high-throughput sequencing, a novel citlodavirus, tentatively named "Myrica rubra citlodavirus 1" (MRV1,accession no. OP374189), was isolated from the leaves of Myrica rubra in Yunnan exhibiting narrow deformity of leaf tips, shrinkage, and chlorosis along the veins. The complete genome sequence was determined and analyzed using cloning and Sanger sequencing. MRV1 is a single-stranded circular non-enveloped DNA virus with a genome size of 3775 nucleotides and contains six open reading frames (ORFs). The virion-sense genome strand encodes a coat protein (CP, nt 750-1,493, 247 aa), two hypothetical movement proteins (V3, nt 382-666, 94 aa; and V2, nt 461-895, 144 aa), and one movement protein (MP, nt 1,527-2,438, 303 aa). The complementary strand of the genome encodes two replication proteins (RepA, nt 3,712-2,834, 292 aa; Rep, nt 2,867-2,553, 104 aa). The MRV1 genome contains the stem-loop motif 5'-TAATATTAC-3', which is a highly conserved nonanucleotide motif found in the origin of virion-strand replication in geminiviruses. Genome sequence alignment analysis showed that citrus chlorotic dwarf associated virus (CCDaV, accession no. JQ920490) shared the highest nucleotide sequence similarity (66.10% identity) with MRV1. Phylogenetic analysis showed that CCDaV is the closest known relative of MRV1, and that these viruses clustered in a single branch within a clade consisting of citlodaviruses. These results indicate that MRV1 should be regarded as a new species of the genus Citlodavirus in the family Geminiviridae.

Conserved hierarchical gene regulatory networks for drought and cold stress response in Myrica rubra.

Stress response in plant is regulated by a large number of genes co-operating in diverse networks that serve multiple adaptive process. To understand how gene regulatory networks (GRNs) modulating abiotic stress responses, we compare the GRNs underlying drought and cold stresses using samples collected at 4 or 6h intervals within 48h in Chinese bayberry (Myrica rubra). We detected 7,583 and 8,840 differentially expressed genes (DEGs) under drought and cold stress respectively, which might be responsive to environmental stresses. Drought- and cold-responsive GRNs, which have been built according to the timing of transcription under both abiotic stresses, have a conserved trans-regulator and a common regulatory network. In both GRNs, basic helix-loop-helix family transcription factor (bHLH) serve as central nodes. MrbHLHp10 transcripts exhibited continuous increase in the two abiotic stresses and acts upstream regulator of ASCORBATE PEROXIDASE (APX) gene. To examine the potential biological functions of MrbHLH10, we generated a transgenic Arabidopsis plant that constitutively overexpresses the MrbHLH10 gene. Compared to wild-type (WT) plants, overexpressing transgenic Arabidopsis plants maintained higher APX activity and biomass accumulation under drought and cold stress. Consistently, RNAi plants had elevated susceptibility to both stresses. Taken together, these results suggested that MrbHLH10 mitigates abiotic stresses through the modulation of ROS scavenging.

Myricetin improves pathological changes in 3×Tg-AD mice by regulating the mitochondria-NLRP3 inflammasome-microglia channel by targeting P38 MAPK signaling pathway

BackgroundAlzheimer's disease (AD) represents the common neurodegenerative disease featured by the manifestations of cognitive impairment and memory loss. AD could be alleviated with medication and improving quality of life. Clinical treatment of AD is mainly aimed at improving the cognitive function of patients. Donepezil, memantine and galantamine are commonly used drug. But they could only relieve AD, not cure it. Therefore, new treatment strategies focusing on AD pathogenesis are of great significance and value. Myricetin (Myr) is a natural flavonoid extracted from Myrica rubra. And it shows different bioactivities, such as anti-inflammation, antioxidation as well as central nervous system (CNS) activities. Nonetheless, its associated mechanism in treating AD remains unknown. PurposeHere we focused on investigating Myr's effect on treating AD and exploring if its protection on the nervous system activity was associated with specifically inhibiting P38 MAPK signaling pathway while regulating mitochondria-NLRP3 inflammasome-microglia. Study design and methodsThis work utilized triple transgenic mice (3 × Tg-AD) as AD models and Aβ25–35 was used to induce BV2 cells to build an in vitro AD model. Behavioristics, pathology and related inflammatory factors were examined. Molecular mechanisms are investigated by western-blot, immunofluorescence staining, CETSA, molecular docking, network pharmacology. ResultsAccording to our findings, Myr could remarkably improve memory loss, spatial learning ability, Aβ plaque deposition, neuronal and synaptic damage in 3 × Tg-AD mice through specifically inhibiting P38 MAPK pathway activation while restraining microglial hyperactivation. Furthermore, Myr promoted the transformation of microglial phenotype, restored the mitochondrial fission-fusion balance, facilitated mitochondrial biogenesis, and restrained NLRP3 inflammasome activation and neuroinflammation. For the in-vitro experiments, P38 agonist dehydrocorydaline (DHC) was utilized to confirm the key regulatory role of P38 MAPK signaling pathway on the mitochondria-NLRP3 inflammasome-microglia channel. ConclusionsOur results revealed the therapeutic efficacy of Myr in experimental AD, and implied that the associated mechanism is possibly associated with inhibiting tmitochondrial dysfunction, activating NLRP3 inflammasome, and neuroinflammation which was mediated by P38 MAPK pathway. Myr is the drug candidate in AD therapy via targeting P38 MAPK pathway.

Comparing the Volatile and Soluble Profiles of Fermented and Integrated Chinese Bayberry Wine with HS-SPME GC–MS and UHPLC Q-TOF

To evaluate the flavor characteristics of Chinese bayberry alcoholic beverages, fermented bayberry wine (FBW) and integrated bayberry wine (IBW) were investigated for their volatile and soluble profiles using HS-SPME GC-MS and UHPLC Q-TOF and were analyzed with multidimensional statistical analysis, including PCA and OPLS-DA. The volatile compounds 1-pentanol, β-caryophyllene and isopentanol were only detected in IBW. β-caryophyllene, the key flavor component of bayberry, was found to be the most abundant volatile compound in IBW (25.89%) and was 3.73 times more abundant in IBW than in FBW. The levels of ethyl octanoate, ethyl nonanoate, and ethyl decanoate were also several times higher in IBW than in FBW. These compounds contributed to the strong bayberry aroma and better fruity flavor of IBW. On the other hand, high levels of ethyl acetate and octanoic acid in FBW, representing pineapple/overripe or sweat odor, were key contributors to the fermented flavor of FBW. Soluble sugars, such as sucrose, D-glucose, and D-tagatose, as well as amino acids, such as L-glutamate and L-aspartate, had much higher levels in IBW. The anthocyanin pigment cyanidin 3-glucoside, which generates red color, was also higher in IBW. On the other hand, most of the differentially expressed alcohols, acids, amino acids, purines/pyrimidines and esters were present in higher concentrations in FBW compared to IBW. This demonstrated that IBW has a much sweeter and more savory taste as well as a better color generated by more anthocyanins, while FBW presents a more acidic and drier taste as well as a complex formation of alcohols and esters. The study also prompts the need for further research on the flavor profiles of IBW and its potential application and market value.

AN UPDATED REVIEW ON OVARIAN CANCER

Ovarian cancer is the most widespread type of gynecological malignancy that causes mortality, with a higher incidence of about 2% for women. It is a cell growth that develops in the ovaries. The cells may penetrate and wreak havoc on healthy bodily tissue because they reproduce swiftly. Currently the treatment for this disease involves chemotherapy and surgery. Chemotherapy can cause long term side effects and More research on medicinal plants like Chinese bayberry, Catha edulis, Berberine, Rutideaparviflora, Schisandrachinensis, Adhatodavasica, is needed to find a safer dosage forms which can be used to treat ovarian cancer. This review article is mainly focused on providing inputs on diagnosis, treatment and prevention of ovarian cancer.

First report of Epicoccum sorghinum causing leaf spot on Basella alba in Malaysia.

Basella alba (family Basellaceae) is a perennial vine that serves as an edible leaf vegetable in Malaysia. In May 2021, red spots were observed on leaf samples of B. alba in Lido, Sabah Province (5°56'39.1"N, 116°04'47.6"E). The disease severity was about 20% with 10% incidence. The spots enlarged and coalesced into larger necrotic spots. Small pieces (5 x 5 mm) of infected leaves were excised from three plants, and then surface disinfected based on Khoo et al. (2022). One fungal isolate (Lido01) was isolated and cultured on potato dextrose agar (PDA) at 25°C. A single isolate with cottony aerial mycelia and pink concentric rings was observed on the upper surface of the culture. Unicellular and multicellular chlamydospores were observed, and measured 7.1 to 14.3. × 17.8 to 74.5 μm. Conidia were unicellular, hyaline, oval, and measured 3.8 to 5.2 x 1.7 to 2.7 μm (n= 20). Pycnidia were spheroid, and measured 66.2 to 114.3 x 44.1 to 86.1 μm (n= 20). Genomic DNA was extracted from fresh mycelia according to the extraction method of Khoo et al. (2022a and 2022b). ITS1/ITS4, LR0R/LR7, ACT512F/ACT783R, and T10/Bt2b primers were used to amplify the internal transcribed spacer (ITS), large subunit (LSU), actin (ACT), and tubulin (TUB) genes, respectively (O'Donnell and Cigelnik, 1997; Chen et al. 2021). PCR products were Sanger sequenced by Apical Scientific Sdn. Bhd. (Serdang, Malaysia). Sequences of isolate Lido01 were deposited in GenBank as OM501130 (ITS), OM501128 (LSU), OM513916 (ACT) and OM513917 (TUB). Respective gene sequences of this isolate showed 100% homology to ITS sequence of isolate BPL01 (OM453926) (507/507 bp), LSU sequence of isolate BPL01 (OM453925) (1328/1328 bp), ACT sequence of isolate CZ01 (MN956831) (275/275 bp) and TUB sequence of isolate BJ-F1 (MF987525) (556/556 bp). The sequences of Lido01 established a supported clade (99% bootstrap value) to the related Epicoccum sorghinum type sequences, according to phylogenetic analysis using maximum likelihood based on the concatenated ITS, ACT, and TUB sequences. Morphological characters also matched the description of E. sorghinum (Li et al. 2020). Koch's postulates were tested as described by Chai et al. (2017) with modification by spray inoculation (106 spores/ml) on the leaves of three healthy one-month-old B. alba, while sterilized distilled water served as the control treatment. Monitoring and incubation were performed in a greenhouse based on Iftikhar et al. (2022). All inoculated leaves developed symptoms as described above by 8 days post-inoculation, whereas no symptoms occurred on controls, thus fulfilling Koch's postulates. The experiment was repeated twice. The reisolated pathogen was morphologically and genetically identical to E. sorghinum. E. sorghinum was reported causing leaf spot on Brassica parachinensis (Yu et al. 2019), Camellia sinensis (Bao et al. 2019), Myrica rubra (Li et al. 2020), Oryza sativa (Liu et al. 2020) and Zea mays (Chen et al. 2021). To our knowledge, this is the first report of E. sorghinum causing leaf spot on B. alba in Malaysia. Our findings have expanded the geographic range and host range of E. sorghinum in Malaysia, though the host range of this isolate is not known.

Declined symptoms in Myrica rubra: The influence of soil acidification and rhizosphere microbial communities

Declined symptoms seriously damaged the growth and development of Myrica rubra, a typical bayberry tree in southern of Zhejiang Province, China. However, knowledge on the mechanisms involved in this decline remains largely unknown. Here, we compared the physicochemical properties, microbial communities as well as metabolites in rhizospheric soil of healthy and declined Myrica rubra trees from four orchards. We found that planting bayberry aggravated soil acidification in all orchards. Surprisingly, compared with healthy trees, the pH decreased and the correlation between nutrients (N, P, K) and metal elements (Cu, Cr, Ni, As, Cd) changed significantly (p < 0.01) in the rhizospheric soil of declined trees. Moreover, bacteria affiliated with Acidobacteriota, Firmicutes, Rozellomycota and Mucoromycota showed considerable enrichment; whereas in genus level, the relative abundance of Acidothermus, Trichoderma, Geminibasidium decreased by 2.9%, 6.7%, and 33.9%, respectively. Besides, the connection in bacterial or fungal communities became more complicated but unstable. These discoveries along with the upregulation of myristic acid and cinnamic acid via metabolome analysis further indicated the aggravated soil acidification and the varied microbial communities and metabolites that resulted in the declined symptoms in Myrica rubra. This study provides new insights into the causes of declined in bayberry trees and can assist the prevention and treatment of declined trees basing on the plant-soil-microbe interactions.

Molecular cloning and functional analysis of Chinese bayberry MrSPL4 that enhances growth and flowering in transgenic tobacco.

Chinese bayberry (Myrica rubra) is an important tree in South China, with its fruit being of nutritional and high economic value. In this study, early ripening (ZJ), medium ripening (BQ) and late ripening (DK) varieties were used as test materials. Young leaves of ZJ, BQ and DK in the floral bud morphological differentiation periods were selected for transcriptome sequencing to excavate earliness related genes. A total of 4,538 differentially expressed genes were detected. Based on clustering analysis and comparisons with genes reportedly related to flowering in Arabidopsis thaliana, 25 homologous genes were identified. Of these, one gene named MrSPL4 was determined, with its expression down-regulated in DK but up-regulated in ZJ and BQ. MrSPL4 contained SBP domain and the target site of miR156, and its total and CDS length were 1,664 bp and 555 bp respectively. The overexpression vector of MrSPL4 (35S::35S::MrSPL4-pCambia2301-KY) was further constructed and successfully transfected into tobacco to obtain MrSPL4-positive plants. Based on the results of qRT-PCR, the relative expression of MrSPL4 was up regulated by 3,862.0-5,938.4 times. Additionally, the height of MrSPL4-positive plants was also significantly higher than that of wild-type (WT), with the bud stage occurring 12 days earlier. Altogether, this study identified an important gene -MrSPL4 in Chinese bayberry, which enhanced growth and flowering, which provided important theoretical basis for early-mature breeding of Chinese bayberry.

First Report of Epicoccum sorghinum Causing leaf spot on Bothriochloa ischaemum in Malaysia.

Bothriochloa ischaemum (family Poaceae) is a perennial weed that can be found in borders of agricultural fields, pastures and roadsides in Malaysia. B. ischaemum is an important phytoremediation species in copper tailings dams (Jia et al. 2020). In December 2021, chlorotic spots with brown halos were observed on leaf samples of B. ischaemum with an incidence of approximately 80% in Penampang, Sabah province (5°56'50.4"N, 116°04'32.8"E). On older leaves, the spots coalesced into larger chlorotic spots. Small pieces (5 x 5 mm) of infected leaves collected from three plants were excised, and then surface sterilized according to Khoo et al. (2022). The fungus was isolated (one isolate was obtained) and cultured on potato dextrose agar (PDA) at 25°C. After 3 days, the colony had cottony aerial mycelia with light purple concentric rings appearing on the underside of the colony. Chlamydospores were produced, either unicellular or multicellular. Conidia were unicellular, hyaline, oval, and were 3.7 to 5.1 x 1.8 to 2.6 μm (n=20). Pycnidia were spheroid, and were 66.4 to 115.3 x 43.1 to 87.4 μm (n=20). Genomic DNA was extracted from fresh mycelia of the fungus based on the extraction method described by Khoo et al. (2022). Amplification of the internal transcribed spacer (ITS) region and large subunit (LSU) of rDNA, and actin (ACT), tubulin (TUB) and RNA polymerase II second largest subunit (RPB2) genes was performed using ITS1/ITS4, LR0R/LR7, ACT512F/ACT783R, T10/Bt2b and RPB2-5F2/RPB2-7cR primers, respectively (O'Donnell and Cigelnik, 1997; Liu et al. 1999; Sung et al. 2007; Chen et al. 2021). The PCR products were sequenced at Apical Scientific Sdn. Bhd.. Sequences were deposited in GenBank as OM453926 (ITS), OM453925 (LSU), OM451236 (ACT), OM451237 (TUB) and OM863567 (RPB2). Sequences of our isolate had 100% homology to ITS of isolate UMS (OK626271) (507/507 bp), LSU of isolate UMS (OM238129) (1328/1328 bp), ACT of isolate CZ01 (MN956831) (275/275 bp), TUB of isolate BJ-F1 (MF987525) (556/556 bp) and RPB2 of isolate HYCX2 (MK836295) (596/596 bp) sequences. Phylogenetic analysis was performed using the maximum likelihood method based on the general time reversible model with a gamma distribution and invariant sites (GTR + G + I) generated from the combined ITS, TUB, LSU and RPB2 sequences, indicating that the isolates formed a supported clade to the related Epicoccum sorghinum type sequences. Morphological and molecular characterization matched the description of E. sorghinum (Li et al. 2020). Koch's postulates were performed by spray inoculation (106 spores/ml) on the leaves of three healthy B. ischaemum plants, using isolate BPL01, while sterilized water was sprayed on three additional B. ischaemum which served as the control. Symptoms similar to those occurred after 6 days post inoculation. No symptoms occurred on controls. The experiment was repeated two more times. The reisolated pathogen was morphologically and genetically identical to E. sorghinum. E. sorghinum was reported previously on Brassica parachinensis (Yu et al. 2019), Camellia sinensis (Bao et al. 2019), Myrica rubra (Li et al. 2020), Oryza sativa (Liu et al. 2020) and Zea mays (Chen et al. 2021) in China. To our knowledge, this is the first report of E. sorghinum causing leaf spot on B. ischaemum in Malaysia. Our findings expand the geographic range and host range of E. sorghinum in Malaysia. B. ischaemum which is a weed in agricultural fields is a host of the pathogen and therefore could be a potential threat to Brassica parachinensis, Camellia sinensis, Oryza sativa and Zea mays in Malaysia. Weed management could be an effective way to eliminate inoculum sources of E. sorghinum.

Genetics and Breeding of Fruit Trees

“Genetics and Breeding of Fruit Trees”, published in Horticulturae, is a collection of 11 manuscripts focusing on commercially important fruit crops, such as apple, peach, pear, kiwi, persimmon, blueberry, and red bayberry [...]

Residue Analysis and Dietary Risk Assessment of Metalaxyl in Chinese Bayberry and Dendrobium officinale

Metalaxyl is frequently used to protect a variety of crops from fungal diseases. This study aims to establish a method for the determination of metalaxyl in Chinese bayberry, fresh Dendrobium officinale (D. officinale), and dried D. officinale by gas chromatography-tandem mass spectrometry (GC-MS/MS) and further assess dietary risk. The samples were extracted with acetonitrile and purified by the dispersed solid phase extraction method. Chinese bayberry, fresh D. officinale, and dried D. officinale samples were collected from Hangzhou and Zhangzhou in 2021 to clarify metalaxyl residue levels. The metalaxyl was quantitated by the external standard method. In the range of 0.001–0.1 mg L−1, there was good linearity under the optimal conditions. The recoveries ranged from 83.90% to 110.47%, with relative standard deviations ranging from 0.86% to 5.81%. The detection rates in Chinese bayberry, fresh D. officinale, and dried D. officinale were 97.92%, 49.29%, and 50.71%, respectively. The dietary risk of metalaxyl residues in Chinese bayberry, fresh D. officinale, and dried D. officinale was acceptable for consumers.

不同林分土壤磷形态与磷酸酶特征

PDF HTML阅读 XML下载 导出引用 引用提醒 不同林分土壤磷形态与磷酸酶特征 DOI: 10.5846/stxb202102130434 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（32171761，U21A20187）；中南林业科技大学研究生科技创新基金项目（CX20191006，CX202102023） Characteristics of soil phosphorus fractions and phosphatases activity in different plantations Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:以湖南省平江县国有芦头林场的次生林以及经人工翻垦种植的油茶（Camellia oleifera）、黄桃（Amygdalus persica）、杨梅（Myrica rubra）和杉木（Cunninghamia lanceolata）四种人工林为研究对象，比较了不同林分土壤理化性质、磷酸酶活性与磷形态特征，分析了三者之间的相关性，探讨了次生林转变为人工林后，土壤磷形态和磷酸酶的变化特征以及驱动土壤磷素形态变化的关键因子。结果表明：（1）次生林土壤有机碳（SOC），全氮（TN）、铵态氮（NH4+-N）含量与磷酸酶活性显著高于其他四种林分。（2）五种林分中土壤残余磷（Residual-P）含量最高，是林地土壤主要的磷素存在形态。林分转变后，黄桃林与杉木林树脂提取态无机磷（Resin-Pi）显著增加，黄桃林与油茶林NaHCO3提取态磷（NaHCO3-Pi、NaHCO3-Po）含量显著增加，而四种人工林的NaOH提取态有机磷（NaOH-Po）含量均显著降低。可利用磷、中等可利用磷与稳定态磷含量及其占全磷的比例在五种林分中差异显著，其中黄桃林与油茶林可利用磷占全磷比例较高；杨梅林和杉木林中等可利用磷占总磷比例较高；油茶林与次生林中稳定态磷所占全磷比例较高。（3）相关分析表明土壤中可利用磷与全钾（TK）呈显著正相关，中等可利用磷与硝态氮（NH3--N）呈显著正相关，稳定态磷与SOC、TN、NH4+-N均呈显著正相关，磷酸酶活性与SOC、TN、NH4+-N显著正相关。综上所述，次生林转变为人工林不仅改变了土壤中总磷的含量，而且影响了不同磷形态之间的转化，导致土壤中磷的赋存状况发生改变。 Abstract:In order to clarify the differences in soil phosphorus forms and phosphatase activities in different forest types, we investigated the characteristics of soil properties, phosphorus (P) fractions, and phosphatase activities in a secondary forest and four artificial plantations (Camellia oleifera, Amygdalus persica, Myrica rubra and Cunninghamia lanceolata) in Lutou National Station for Scientific Observation and Research of Forest Ecosystems, Hunan Province. Correlations among soil properties, phosphorus fractions and phosphatase activities were analyzed, and the influencing factors driving the differences in soil phosphorus forms and phosphatase activities were identified. The results showed that:(1) the contents of soil organic carbon (SOC), total nitrogen (TN), ammonium nitrogen (NH4+-N) and the activities of phosphatase in the secondary forest were higher than in the four plantations. (2) the content of residual-P was the highest in the five forest types, and residual-P was the dominant phosphorus form in forest soils. After forest conversion, resin extractable inorganic P (Resin-Pi) increased significantly in Amygdalus persica and Cunninghamia lanceolata plantations. The contents of NaHCO3 extractable P (NaHCO3-Pi, NaHCO3-Po) increased significantly in Amygdalus persica and Camellia oleifera plantations, whereas the content of NaOH extracted organic P (NaOH-Po) decreased significantly in all plantations. The contents and proportions of easily-available P, moderately-available P and non-available P in soils differed significantly among the five forest types. The proportion of easily-available P in total P was higher in Amygdalus persica and Camellia oleifera plantations than in other forests, while a higher proportion of moderately-available P in total P was found in Myrica rubra plantations and Cunninghamia lanceolata plantations. The proportion of non-available P in total P was higher in Camellia oleifera and the secondary forest compared with other forests. (3) correlation analysis demonstrated that easily-available P was positively correlated with total potassium (TK), moderately-available P was positively correlated with nitrate nitrogen (NH3--N), non-available P was positively correlated with SOC, TN, NH4+-N, and phosphatase activity was positively correlated with SOC, TN, NH4+-N. In conclusion, the conversion of secondary forest to plantations not only changed the soil total P contents, but also affected the transformation of phosphorus forms, resulted in the differences of the occurrence of P in soil. 参考文献 相似文献 引证文献

First Report of Epicoccum sorghinum Causing leaf spot on Platostoma palustre in Malaysia.

Platostoma palustre (family Lamiaceae), locally known as 'Black Cincau', is an herb processed as herbal drinks in Malaysia. In November 2021, brown lesions were observed on leaf samples of P. palustre with an incidence of approximately 10% in a nursery in Penampang, Sabah province (5°55'30.4"N 116°04'35.7"E). The lesions developed into larger chlorotic spots with aging of leaves. Five samples of infected leaves were collected, excised (5 × 5 mm), and then surface sterilized with 75% ethanol for 1 minute, washed with 2% sodium hypochlorite solution for 1 minute, rinsed, and air dried before inoculated onto potato dextrose agar (PDA). Inoculated plates were incubated at 25°C. Three isolates were isolated from the samples, which showed cottony aerial mycelia with light purple concentric rings appeared on the reverse side of the colony after 3 days. Pycnidia which were spheroid and measured 64.0 to 114.1 × 41.2 to 88.0 μm (n= 30). Conidia, unicellular, hyaline, oval and measured 3.8 to 4.9 × 2.0 to 2.7 μm (n= 30). Chlamydospores were observed, either unicellular or multicellular. NaOH test on oatmeal agar positive, brownish red. Further, the genomic DNA of pathogens (UMS, UMS02 and UMS03) was extracted from fresh mycelia (7-day-old) using lysis buffer. Large Sub Unit (LSU), β-tubulin (tub) and RNA polymerase II (RPB2) gene were amplified using LR0R/LR7, T10/Bt2b and RPB2-5F2/RPB2-7cR primers (Rehner and Samuel, 1994; O'Donnell and Cigelnik, 1997; Liu et al. 1999) respectively. The sequences of isolate UMS, UMS02 and UMS03 which deposited in Genbank were OM238129, ON386254, ON386255 (LSU), OM048108, ON366806, ON366807 (tub), and ON003417, ON366804, ON366805 (RPB2). They had 99-100% homology to the LSU (1328/1328 bp) of Epicoccum sorghinum isolate Lido01 (OM501128), tub (422/425 bp) of isolate BJ-F1 (MF987525), and RPB2 (596/596 bp) of isolate HYCX2 (MK836295). Phylogenetic analysis by maximum likelihood method generated from the combined tub, LSU and RPB2 sequences indicated that the isolates formed a supported clade to the related Epicoccum sorghinum type sequences. Morphological, NaOH test and molecular characterization matched the description of E. sorghinum (Boerema et al. 2004; Li et al. 2020). Koch's postulates were performed by spray inoculation (106 conidia/mL) on the leaves of three healthy P. palustre seedlings with isolate UMS, while water was sprayed on three additional P. palustre seedlings served as controls. The plants were maintained in a greenhouse at room temperature 25 to 28°C with a relative humidity of 80 to 90%. All inoculated plants exhibited the symptoms similar to those of the nursery collection occurred after 8 days post inoculation. No symptoms occurred on controls. The experiment was repeated twice. The reisolated pathogen was morphologically identical to E. sorghinum. E. sorghinum was reported previously on Myrica rubra in China (Li et al. 2020). To our knowledge, this is the first report of E. sorghinum causing leaf spot on P. palustre in Malaysia. Our findings expand the host range of E. sorghinum in Malaysia.