Diaporthe taoicola and D. siamensis, Two New Records on Citrus sinensisin China

Two Diaporthe species isolated from fruit of Citrus sinensis in China were characterized based on morphology and multilocus phylogeny of ITS, tef1, and tub2 gene sequences. The phylogeny indicated that the two species match Diaporthe taoicola and D. siamensis. A critical examination of phenotypic characteristics confirmed the phylogenetic results. Diaporthe taoicola was morphologically characterized by producing Alpha conidia with tapering toward both ends. Meanwhile, D. siamensis produced cylindrical or ellipsoidal Alpha conidia with two oil drops. Pathogenicity tests revealed that both species were pathogenic to fruit of C. sinensis. To our knowledge, the two species were firstly reported on Citrus sinensis in China.

Diaporthe taoicola and D. siamensis, Two New Records on Citrus sinensisin China

Two Diaporthe species isolated from fruit of Citrus sinensis in China were characterized based on morphology and multilocus phylogeny of ITS, tef1, and tub2 gene sequences. The phylogeny indicated that the two species match Diaporthe taoicola and D. siamensis. A critical examination of phenotypic characteristics confirmed the phylogenetic results. Diaporthe taoicola was morphologically characterized by producing Alpha conidia with tapering toward both ends. Meanwhile, D. siamensis produced cylindrical or ellipsoidal Alpha conidia with two oil drops. Pathogenicity tests revealed that both species were pathogenic to fruit of C. sinensis. To our knowledge, the two species were firstly reported on Citrus sinensis in China.

Identification and Characterization of Gonatobotryum apiculatum CausingLeaf Spot and Blight on Sinowilsonia henryi

Sinowilsonia henryi is a rare and endangered plant, as well as an endemic species in China.In July 2018, leaf spot and blight disease was observed on S. henryi in Yichang, Hubei,China. A fungus isolated from disease tissues was identified as Gonatobotryum apiculatumbased on morphology and sequence analyses of ITS and LSU regions. Phylogenetic analysesindicated that the species belongs to Dothioraceae (Dothideales). Morphologically, the speciesproduced two distinct types of conidia from authentic media, both conidia weredescribed here. Pathogenicity tests showed that the fungus is a pathogen causing leaf spotson S. henryi. This is the first report of leaf spot and blight disease on S. henryi caused byG. apiculatum in China.

Identification and Characterization of Gonatobotryum apiculatum CausingLeaf Spot and Blight on Sinowilsonia henryi

Sinowilsonia henryi is a rare and endangered plant, as well as an endemic species in China.In July 2018, leaf spot and blight disease was observed on S. henryi in Yichang, Hubei,China. A fungus isolated from disease tissues was identified as Gonatobotryum apiculatumbased on morphology and sequence analyses of ITS and LSU regions. Phylogenetic analysesindicated that the species belongs to Dothioraceae (Dothideales). Morphologically, the speciesproduced two distinct types of conidia from authentic media, both conidia weredescribed here. Pathogenicity tests showed that the fungus is a pathogen causing leaf spotson S. henryi. This is the first report of leaf spot and blight disease on S. henryi caused byG. apiculatum in China.

Morphology and Molecular Characterization of Alternaria argyranthemi on Chrysanthemum coronarium in China

Chrysanthemum coronarium is an economically important plant in Asia, and used medicinally, ornamentally and as a vegetable. In April 2017, leaf spot disease on C. coronarium was observed in Shiyan, Hubei, China. A single-spore isolate was obtained and identified based on morphology and sequence analysis using four regions (rDNA ITS, GAPDH, EF-1α, and RPB2). The results indicated that the fungus is Alternaria argyranthemi. The pathogenicity tests revealed that the species could cause severe leaf spot and blight disease on the host. This is the first report of leaf spot disease on C. coronarium caused by A. argyranthemi in the world, which is also a new record of Alternaria species in China.

Alternaria brassicifolii sp. nov. Isolated from Brassica rapa subsp. pekinensis in Korea

A new species belonging to the genus Alternaria was isolated from the necrotic leaf spots of Brassica rapa subsp. pekinensis in Yuseong district, Daejeon, Korea. It is an occasional isolate, not an etiological agent, which is morphologically similar to A. broccoli-italicae, but differs in conidial size and conidiophore shape. Phylogenetic analysis using the sequence datasets of the internal transcribed spacer (ITS) region of the rDNA, glyceraldehyde-3-phosphate dehydrogenase (gpd), and plasma membrane ATPase genes showed that it is distantly related to A. broccoli-italicae and closely related to Alternaria species in the section Pseudoalternaria, which belonged to a clade basal to the section Infectoriae. Morphologically, the species is unique because it produces solitary conidia or conidial chains (two units), unlike the four members in the section Pseudoalternaria that produce conidia as short branched chains. It exhibits weak pathogenicity in the host plant. This report includes the description and illustration of A. brassicifolii as a new species.

Identification and Characterization of Alternaria iridiaustralis Causing Leaf Spot on Iris ensata in China

In 2016, a severe leaf spot disease was found on Iris ensata Thumb. in Nanjing, China. The symptom was elliptical, fusiform, or irregularly necrotic lesion surrounded by a yellow halo, from which a small-spored Alternaria species was isolated. The fungus was identified as Alternaria iridiaustralis based on morphological characteristics. The pathogenicity tests revealed that the fungus was the causal pathogen of the disease. Phylogenic analyses using sequences of ITS, gpd, endoPG, and RPB2 genes confirmed the morphological identification. This study is the first report of A. iridiaustralis causing leaf spots on I. ensata in China.

Characterization and Pathogenicity of Alternaria burnsii from Seeds of Cucurbita maxima (Cucurbitaceae) in Bangladesh

In the course of survey of endophytic fungi from Bangladesh pumpkin seeds in 2011~2012, two strains (CNU111042 and CNU111043) with similar colony characteristics were isolated and characterized by their morphology and by molecular phylogenetic analysis of the internal transcribed spacer, glyceraldehydes-3-phosphate dehydrogenase (gpd), and Alternaria allergen a1 (Alt a1) sequences. Phylogenetic analysis of all three sequences and their combined dataset revealed that the fungus formed a subclade within the A. alternata clade, matching A. burnsi and showing differences with its other closely related Alternaria species, such as A. longipes, A. tomato, and A. tomaticola. Long ellipsoid, obclavate or ovoid beakless conidia, shorter and thinner conidial size (16~60 [90] x 6.5~14 [~16] microm) distinguish this fungus from other related species. These isolates showed more transverse septation (2~11) and less longitudinal septation (0~3) than did other related species. Moreover, the isolate did not produce any diffusible pigment on media. Therefore, our results reveal that the newly recorded fungus from a new host, Cucurbita maxima, is Alternaria burnsii Uppal, Patel & Kamat.

Characterization and Pathogenicity of Alternaria vanuatuensis, a New Record from Allium Plants in Korea and China

Alternaria from different Allium plants was characterized by multilocus sequence analysis. Based on sequences of the beta-tubulin (BT2b), the Alternaria allergen a1 (Alt a1), and the RNA polymerase II second largest subunit (RPB2) genes and phylogenetic data analysis, isolates were divided into two groups. The two groups were identical to representative isolates of A. porri (EGS48-147) and A. vanuatuensis (EGS45-018). The conidial characteristics and pathogenicity of A. vanuatuensis also well supported the molecular characteristics. This is the first record of A. vanuatuensis E. G. Simmons & C. F. Hill from Korea and China.

A Novel Alternaria Species Isolated from Peucedanum japonicum in Korea

We isolated and examined a new Alternaria sp., which causes leaf spots on Peucedanum japonicum in Korea, by using molecular and morphological methods. Phylogenetic analysis based on a combined internal transcribed spacer region analysis and two protein-coding genes (gpd and Alt a1) demonstrated that the causal fungus was most closely related to A. cinerariae and A. sonchi, and relevant to A. brassicae. However, conidial morphology indicated that it is a novel species within the genus Alternaria, and therefore we have assigned the fungus a new name in this study.

Biocontrol Activity of Bacillus amyloliquefaciens CNU114001 against Fungal Plant Diseases

A total of 62 bacterial isolates were obtained from Gomsohang mud flat, Mohang mud flat, and Jeju Island, Republic of Korea. Among them, the isolate CNU114001 showed significant antagonistic activity against pathogenic fungi by dual culture method. The isolate CNU114001 was identified as Bacillus amyloliquefaciens by morphological observation and molecular data analysis, including 16SrDNA and gyraseA (gyrA) gene sequences. Antifungal substances of the isolate were extracted and purified by silica gel column chromatography, thin layer chromatography, and high performance liquid chromatography. The heat and UV ray stable compound was identified as iturin, a lipopeptide (LP). The isolate CNU114001 showed broad spectrum activity against 12 phytopathogenic fungi by dual culture method. The semi purified compound significantly inhibits the mycelial growth of pathogenic fungi (Alternaria panax, Botrytis cinera, Colletotrichum orbiculare, Penicillium digitatum, Pyricularia grisea and Sclerotinia sclerotiorum) at 200 ppm concentration. Spore germ tube elongation of Botrytis cinerea was inhibited by culture filtrate of the isolate. Crude antifungal substance showed antagonistic activity against cucumber scleotiorum rot in laboratory, and showed antagonistic activity against tomato gray mold, cucumber, and pumpkin powdery mildew in greenhouse condition.

New Records of Endophytic Paecilomyces inflatus and Bionectria ochroleuca from Chili Pepper Plants in Korea

Two new species of endophytic fungi were encountered during a diversity study of healthy tissues of chili pepper plants in Korea. The species were identified as Paecilomyces inflatus and Bionectria ochroleuca based on molecular and morphological analyses. Morphological descriptions of these endophytic isolates matched well with their molecular analysis. In the present study, detailed descriptions of internal transcribed spacer regions and morphological observations of these two fungi are presented.

A New Record of Penicillium cainii from Soil in Korea

Twenty Penicillium isolates were recovered during the investigation of fungal community in the soil samples collected from Wando (Jeonnam Province, Korea). Among them, one species was identified and described as P. cainii based on phylogentic analysis of internal transcribed spacer and beta-tubulin (BT2) genes and morphological characteristics. This is a first report of P. cainii in Korea.

Molecular and Morphological Characterization of Endophytic Heterobasidion araucariae from Roots of Capsicum annuum L. in Korea

A species of Heterobasidion was encountered during a diversity study of endophytic fungi from healthy root tissues of chili pepper (Capsicum annuum L.) in Korea. The fungal species (CNU081069) was identified as Heterobasidion araucariae based on phylogenetic analyses of the internal transcribed spacer and translation elongation factor gene sequences. Morphological descriptions of the endophytic isolate matched well with the previous references and supported the molecular identification. The fungus Heterobasidion araucariae CNU081069 is new to Korea.

First Report on Isolation of Penicillium adametzioides and Purpureocillium lilacinum from Decayed Fruit of Cheongsoo Grapes in Korea

Two species, Penicillium adametzioides and Purpureocillium lilacinum, were isolated from decayed grapes (cv. Cheongsoo) in Korea. Each species was initially identified by phylogenetic analysis of a combined dataset of two genes. Internal transcribed spacer (ITS) and beta-tubulin (BT2) genes were used for identification of Penicillium adametzioides, and ITS and partial translation elongation factor 1-alpha (TEF) genes were used for identification of Purpureocillium lilacinum. Morphologically, they were found to be identical to previous descriptions. The two species presented here have not been previously reported in Korea.

Molecular Characterization and Morphology of Two Endophytic Peyronellaea Species from Pinus koraiensis in Korea

Species of Phoma and its allies were isolated during a survey on the diversity of endophytic fungi associated with pine trees in Korea. Based on the phylogenetic analyses of internal transcribed spacer and beta-tubulin gene sequences, two Phoma-like species from the needles of Pinus koraiensis were identified as Peyronellaea calorpreferens and P. glomerata. They were also morphologically identified based on the previous descriptions. Here, we report P. calorpreferens and P. glomerata being present in Korea as endophytic fungi in Pinus koraiensis.

First Report of Foliar Blight on Dendropanax morbifera Caused by Alternaria panax

Leaf spot and blight disease was observed on two-year-old seedlings of Dendropanax morbifera (Korean name: Hwangchil tree) during July of 2008 in Jindo Island, Korea. Symptoms included yellow-brown to dark brown irregularly enlarged spots frequently located along the veins of leaves. The lesions were often surrounded by chlorotic haloes. Severe leaf blight and subsequent defoliation occurred when conditions favored disease outbreak. The causal organism of the disease was identified as Alternaria panax based on morphological characteristics and sequence analysis of the internal transcribed spacer region of rDNA. A. panax isolates induced leaf spots and blight symptoms not only on D. morbifera but also on the other members of Araliaceae tested. This is the first report of foliar blight caused by A. panax on D. morbifera.

Developmental regulation of long term potentiation at layer II/III to II/III synapses of rat visual cortex / 生理学报

In the present research, patch-clamp whole-cell recording was used to study the developmental changes of the internal horizontal synaptic plasticity in layer II/III of rats' primary visual cortices. Pairing stimulation was used to induce long term potentiation (LTP) of neurons in layer II/III from layer II/III and layer IV. The data indicate that: (1) Responses of layer II/III neurons can be evoked independently at II/III-II/III and IV-II/III synapses by horizontal and vertical stimulations; (2) LTP can be induced from neurons in the layer II/III by horizontal tetanic stimulation at II/III-II/III synapses till postnatal day12 (P12, before eyes open); (3) Meanwhile, only short term potentiation (STP) at IV-II/III synapses can be induced by horizontal tetanic stimulation before eyes open; (4) After P12, a robust LTP at IV-II/III synapses can be induced by horizontal tetanic stimulation; (5) At P14, when vertical and horizontal tetanic stimulations were given to the same neuron, the LTP at IV-II/III synapses was weaker than that induced by vertical stimulation alone, suggesting that vertical synaptic modification was negatively regulated by horizontal inputs when two-direction synaptic inputs were presented at the same time; (6) Spontaneous responses of AMPA receptors (AMPARs) in the layer II/III neuron of rats' primary visual cortices are regulated by the development. The frequency of AMPARs-mediated postsynaptic currents was at a low level before eyes open, increased sharply at P12-P14, and slightly decreased after P18. And the amplitude of spontaneous AMPARs currents slowly decreased after P12. The results demonstrated that both the strength of horizontal synaptic modification and the effects of horizontal inputs on the vertical synaptic connection are regulated by the development. II/III-II/III synaptic communication has dual effects on the IV-II/III synapses, which may be involved in a competitive machinery of neural circuitry maturation and the formation of visual function columns.

Underlying mechanism for prolongation of action potential duration in ventricular cardiomyocytes of rats suffered from thermal injury / 生理学报

Severe thermal injury causes prolongation of action potential duration (APD) in cardiomyocytes, which results in cardiac dysfunction by inducing disturbance of calcium dyshomeostasis in cardiac myocytes. However, the underlying mechanism for APD prolongation remains unclear. In the present study, we examined the major action potential repolarization-related ion channel currents in rat ventricular cardiomyocytes, including transient outward potassium current (I(to)), inward rectifier potassium current (I(K1)) and L-type Ca(2+) current (I(Ca-L)) to investigate the alterations of these currents, which might account for the pathogenesis of APD prolongation induced by thermal injury. Twelve hours after approximately 40% of the total body surface area, full-thickness (third-degree) cutaneous thermal injury was produced in rats, ventricular cardiomyocytes were isolated from the hearts with systolic and diastolic dysfunction. APD was found to be markedly prolonged, while APD(50) and APD(90) in ventricular cardiomyocytes from rats with thermal injury were (46.02+/-3.78) ms and (123.24+/-12.48) ms (n=19), respectively, significantly longer than (23.28+/-4.85) ms and (72.12+/-3.57) ms (n=17, P<0.01) in ventricular cardiomyocytes from sham rats. Thermal injury remarkably suppressed Ito density in ventricular cardiomyocytes. Ito density at +60 mV was decreased from (34.15+/-3.78) pA/pF (n=20) in sham group to (20.39+/-1.98) pA/pF (n=25, P<0.01) in thermal injury group, and the decrease extended from -30 to +60 mV. Similarly, current densities of I(K1) from -120 to -80 mV in thermal injury group were also significantly lower than that in sham group. In contrast, we failed to detect any alterations in I(Ca-L) density, and voltage-dependence of activation and inactivation in thermal injury group, compared with that in sham group. Taken together, our data suggest that thermal injury results in function downregulation of transient outward potassium channels and inward rectifier potassium channels, which contributes, at least in part, to APD prolongation and subsequent cardiac dysfunction.

KCNE2 modulates the function of Kv4.3 channel / 南方医科大学学报

<p><b>OBJECTIVE</b>To understand the role of KCNE2 in functional regulation of Kv4.3, the major alpha subunit of transient outward current (I(to)) in human heart.</p><p><b>METHODS</b>The cDNAs of Kv4.3 or Kv4.3 plus KCNE2 were transfected into COS-7 cells and 24-36 h after the transfection, the channel proteins were expressed in the surface membrane of the cells and the channel currents were recorded with patch-clamp technique in whole-cell mode.</p><p><b>RESULTS</b>KCNE2 played an important role in modulating the channel function. The recorded current density was decreased in cells co-expressing KCNE2 and Kv4.3 to 152.96-/+33.71 pA/pF (n=16) as compared with Kv4.3-expressing cells with a mean current density of 375.13-/+112.87 pA/pF (n=11). At the recording voltage of 60 mV, KCNE2 increased the time to peak (TTP) of the current. TTP in only Kv4.3-expressing cells was 4.82-/+0.32 ms (n=11), significantly shorter than the TTP of 20.41-/+2.13 ms (n=16) in cells co-expressing Kv4.3 and KCNE2 (P<0.05). In the presence of KCNE2, the voltage-dependent inactivation of Kv4.3 showed a positive shift. The voltage of half maximum inactivation (V(0.5)) was decreased significantly from -53.62-/+1.24 mV (n=8) in Kv4.3 group to -46.58-/+1.6 mV (n=10) in KCNE2 co-expression group (P<0.05). KCNE2 accelerated the recovery of the channel from inactivation, reducing the recovery time constant (tau) from 193.43-/+17.98 ms to 137.71-/+18.29 ms.</p><p><b>CONCLUSION</b>KCNE2 might serve as an important beta subunit and play a role in the regulation of I(to) function in human heart.</p>