Size Of Conidia Research Articles

First Report of Leaf Spot on Oil Palm Caused by Phyllosticta capitalensis in Malaysia

HomePlant DiseaseVol. 104, No. 1First Report of Leaf Spot on Oil Palm Caused by Phyllosticta capitalensis in Malaysia PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Leaf Spot on Oil Palm Caused by Phyllosticta capitalensis in MalaysiaA. Nasehi, H. Sathyapriya, and M. Y. WongA. Nasehihttp://orcid.org/0000-0002-5926-0742Institute of Plantation Studies, Universiti Putra Malaysia, 43400 Serdang, Selangor, MalaysiaSearch for more papers by this author, H. SathyapriyaInstitute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, 43400 Serdang, Selangor, MalaysiaSearch for more papers by this author, and M. Y. Wong†Corresponding author: M. Y. Wong; E-mail Address: muiyun@upm.edu.myhttp://orcid.org/0000-0002-6944-4860Institute of Plantation Studies, Universiti Putra Malaysia, 43400 Serdang, Selangor, MalaysiaDepartment of Plant Protection, Faculty of Agriculture, Universiti Putra Malaysia, 43400 Serdang, Selangor, MalaysiaSearch for more papers by this author AffiliationsAuthors and Affiliations A. Nasehi1 H. Sathyapriya2 M. Y. Wong1 3 † 1Institute of Plantation Studies, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia 2Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia 3Department of Plant Protection, Faculty of Agriculture, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia Published Online:6 Nov 2019https://doi.org/10.1094/PDIS-06-19-1232-PDNAboutSectionsSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat Oil palm (Elaeis guineensis Jacq.) is the most economically important crop in Malaysia and the world’s highest yielding oil crop. In March 2018, irregular spots with gray centers, dark brown edges, and chlorotic halos were observed on the leaves of oil palm trees of Tenera genotype planted at Block A, University Agriculture Park, Universiti Putra Malaysia, Malaysia. The area of production is 8 ha of conventional farming with temperature and humidity ranging from 33 to 34°C and 30 to 70%, respectively. There were a total of 1,192 oil palm trees in the area analyzed, and the disease incidence was estimated to be approximately 20%. Twelve leaf sections (5 mm2) of four diseased leaves from four different symptomatic oil palm trees were surface sterilized in 1% sodium hypochlorite for 2 min, rinsed twice with distilled water, dried on sterilized tissue paper, plated on potato dextrose agar (PDA) plates, and incubated at 27 ± 1°C for 14 days in the dark. A total of 12 single-spore isolates were obtained from all sampled leaf tissues. The single colonies of all fungal isolates were olivaceous greenish to olivaceous black with an irregular light olive margin on PDA. Conidia were obpyriform or nearly elliptic, unicellular, with a hyaline, unstable apical appendage, 5 to 12 µm long. The size of conidia was 10 to 15 μm in length and 6 to 8 μm in width. These morphological characters were consistent with the original description of Phyllosticta capitalensis (Glienke et al. 2011; Hennings 1908). For fungal identification to species level, the internal transcribed spacer region (ITS) of the representative isolate UPM-Ph1 was amplified utilizing the universal primers ITS5/ITS4 (White et al. 1990) and then sequenced. The 620-bp ITS sequence was deposited in GenBank under accession number MH699964. The phylogenetic analysis confirmed that the isolate UPM-Ph1 belonged to P. capitalensis, and it shares 100% homology with the ITS sequence of the reference pathogenic P. capitalensis strain CPC18884 (GenBank JF261465), which was isolated from the host Stanhopea graveolens in Brazil, as reported by Glienke et al. (2011). Pathogenicity testing was conducted by artificial inoculation of healthy oil palm (Tenera GH 500 series) leaves with isolate UPM-Ph1 under the conditions of 9-h day/15-h night cycle and using LED white light. Four leaves were wound inoculated in three parts with a sterile scalpel and pipetting a 10-µl droplet of a conidial suspension (106 conidia/ml) on each wound. Another four leaves were wound inoculated with sterilized distilled water and served as a control. All inoculated leaves and control leaves were incubated in a chamber with 98% relative humidity at 27 ± 1°C. After 7 days, typical lesions identical to those observed in the field appeared on the inoculated leaves but not on control leaves. P. capitalensis was successfully reisolated only from the inoculated leaves and identified by morphological observations. The pathogenicity test was repeated, and the same typical lesions were observed. P. capitalensis has been reported as a weak plant pathogen that causes various diseases in plants (Wikee et al. 2013a, 2013b). Unsuccessful reisolation of the fungus from the control leaves confirmed that the control plants were not already latently infected with the pathogen. To our knowledge, this is the first report of P. capitalensis causing leaf spot disease of oil palm in Malaysia. This pathogen is capable of affecting the health and yield of oil palm trees in the plantations substantially if no control measure is in place. Therefore, further investigation is needed to determine the distribution of P. capitalensis in oil palm plantations in Malaysia.The author(s) declare no conflict of interest.

Transitions from Single- to Multi-Locus approach in determining cryptic and describing new species within Beauveria genus (Cordycipitaceae, Hypocreales): a review

Beauveria is one of the most prominent genus within entomopathogenic fungi. This genus is an asexually reproducing fungus which includes morphologically indistinguishable species. The delimitation of species in Beauveria is controversial due to the lack of distinctive taxonomic features and the extensive overlap in the shape and the sizes of conidia. Moreover, cryptic species have been revealed in Beauveria using molecular tools making species identification a challenge within the genus. Since 1990s, the development of reliable molecular tools based on DNA sequences has become increasingly useful for species delineation and recognition allowing a best application of genealogical concordance phylogenetic species recognition. Actually, specimen’s taxonomy becomes tightly dependent on DNA based-data. Single-gene based on the internal transcribed spacers (ITS) region is the common barcoding DNA, but has reached its limit in delimiting closely related species, including Beauveria species. With the advances in sequencing technology, the focus has been shifted from single to multiple locus data to identify fungal isolates adapting genealogical concordance phylogenetic species recognition (GCPSR) criterion. Multi-locus approach has been increasingly more applied in assigning fungal samples to a given species and significantly improves Beauveria taxonomy raising the number of Beauveria species to heighten species.

Occurrence of mycoparasitic fungi Sphaerellopsis paraphysata on pearl millet rust pathogen, Puccinia substriata in India

A mycoparasite was isolated on the rust infected pearl millet crop. It was isolated from an unusual pycnidia which was present along with the uredospores of rust. It reduced the uredial inoculum to a considerable extent. The morphology and molecular characters of the mycoparasite was studied. Its role as hyperparasite was established using Scanning Electron Micrographs, which clearly showed coiling and puncturing of uredospores of Puccinia substriata, by the mycelia of S. paraphysata. The confirmatory studies on the positive pathogenicity on rust fungi, showed a colourless septate mycelium, with an average conidial size of 9.27-12.92 ×2.55-5.87 µm and pycnidial size of 76.14-198.04×56.25-184.19 µm. The 540bp amplicon size of ITS sequence showed 96% similarity with S. paraphysata. The spore germination of Puccinia substriata on pearl millet leaves was reduced by 76%, 56%, 70% and the disease severity percentage was 13.3% on an average whereas in control it was 86.6%. The intimate association between S. paraphysata and Puccina substriata was proved by ultra microscopic structures in this investigation.

Inhibitory effects of leaf extract of Lawsonia inermis on Curvularia lunata and characterization of novel inhibitory compounds by GC–MS analysis

Plants produce a high diversity of natural products with a prominent function in the protection against microbial pathogens on the basis of their toxic effect on growth and reproduction. In the present study, effect of partially purified acetone fraction of L. inermis leaves on various cytomorphological parameters i.e. mycelium width, conidial size, etc. of test fungi and fraction was subjected to confirming the presence of primary and secondary metabolites by rapid qualitative phytochemical tests, chromatographic methods such as TLC, column chromatography, GC–MS, etc. which were responsible for the inhibition of growth of test pathogen conidial size of Curvularia lunata decreased up to 64.76% at 0.039 μg/ml concentration of the extract. Mycelial width of C. lunata increased up to 55.91% at 0.312 μg/ml concentration of the extract. Carbohydrate, steroids, volatile oils, flavonoids, and tannins were found to be present in acetone extract of L. inermis leaf. Total of 7 bands were observed in TLC fingerprinting of L. inermis acetone fraction. Total of 10 fractions were collected from the column chromatography. Fractions which show the most significant antifungal activity against the test fungus was subjected to further GC–MS analysis for the separation and identification of active principle. GC–MS analyses show the presence of total 6 constituents i.e. hexacosane, octadecane, docosane, heptacosane methyl, octacosane, and tetracosane.

Powdery mildew caused by Golovinomyces spadiceus on wild sunflower in Sinaloa, Mexico

Wild sunflower is a common weed that grows among agricultural crops in many parts of the world, where it is both highly invasive and competitive and can serve as a reservoir for plant pathogens. Recently, signs of powdery mildew (PM) were observed on wild sunflower plants in Sinaloa, Mexico. The aim of this study was to identify the causal agent based on morphology and molecular techniques, and to determine pathogenicity on sunflower plants. Phylogenetic analysis of the ITS region grouped the sequences within lineage III of the genus Golovinomyces, which comprises pathogenic species of the plant tribe Heliantheae of Asteraceae. However, within this lineage, the three species belonging to this group: G. circumfusus, G. ambrosiae and G. spadiceus, cannot be differentiated based on the ITS region due to their close phylogenetic relationship. Morphometric analyses, particularly conidium size and germ tube morphology, confirmed the identity of the fungus infecting wild sunflowers as G. spadiceus. Inoculation tests under greenhouse conditions confirmed the pathogenicity of G. spadiceus in wild sunflower and in the commercial sunflower hybrid SYN3950HO. Signs of powdery mildew displayed on sunflower were similar to those observed under field conditions and in two independent inoculation tests. Our results confirm that wild sunflower is a potential source of G. spadiceus inoculum for commercial sunflower during the autumn–winter growing season.

Diversity in Alternaria brassicae (Berk.) Sacc. isolates and characterization of host response in different oilseed Brassica species

Alternaria brassicae (Berk.) Sacc., a necrotrophic fungus devastating oilseed Brassica crops in India, causes up to 47% reduction in seed yield. So the study is conducting to develop the knowledge about the variability of A. brassicae in terms of cultural, morphological, pathogenic characters and their effects on different Brassica species of rapeseed mustard, for minimizing the losses caused by A. brassicae and help to stabilize the rapeseed mustard production. In variability study, all the isolates showed cultural, morphological variability. Average conidial length was maximum in isolate Ab2 (21.7μ) followed by Ab4 (20.7μ) and minimum in Ab8 (15.6μ). Septation in conidia, both horizontal and vertical also showed variation in different isolates. Finally it was revealed that smallest size of conidia in isolates Ab8 and longest size of conidia in isolates Ab4 were observed. On solid medium, maximum sporulation was observed in Ab7 followed while minimum sporulation recorded in Ab8. On liquid medium, maximum sporulation was observed in Ab7 while minimum sporulation recorded in Ab8. All the isolates showed the variability in qualitative characters i.e. spot colour, presence or absence of central point, concentric rings and yellow halo and as well as in quantitative characters i.e. incubation period and Percent Disease Index.

Multigene phylogeny and morphology of Alternaria reveal a novel species and a new record in China

Two Alternaria species, A. carotiincultae and A. glehniae sp. nov. are isolated from necrotic leaf symptoms of Ligusticum chuanxiong Hort. and Glehnia littoralis Fr. Schmidt ex Miq in China, respectively. The two species are determined as distinct species belonging to sect. Radicina of Alternaria based on morphology and a multigene analysis of ITS, EF-1α, RPB2 and ATPase sequences. Alternaria glehniae is illustrated here as a novel species because the conidial size, septa and sporulation patterns are different from its closely related species. A. carotiincultae is also described as a new record in China.

Investigation of Fungi Causing Twig Blight Diseases on Peach Trees in South Carolina.

A survey of fungal pathogens causing twig blight on commercial peach trees was conducted in South Carolina in the fall of 2016. Shoots with cankers, pycnidia, and dieback were collected from six locations around the state. Isolates obtained from these samples were identified as Botryosphaeria obtusa, Phomopsis amygdali, Leucostoma persoonii, and Cytospora sp., based on colony morphology, conidia size and shape, and ribosomal DNA sequence analysis. L. persoonii was the most prevalent species and was isolated in five of the six locations, followed by P. amygdali and B. obtusa. The sensitivity of representative isolates of B. obtusa, P. amygdali, and L. persoonii to fungicides of different FRAC codes was evaluated. All species tested were sensitive to thiophanate-methyl (FRAC 1) and pyraclostrobin and azoxystrobin (both FRAC 11), whereas all species were resistant to boscalid and fluopyram (both FRAC 7). P. amygdali and B. obtusa were sensitive to difenoconazole and propiconazole (both FRAC 3), whereas L. persoonii was moderately resistant. L. persoonii was the most virulent species based on expansion of mycelium in the cambium layer of 2-year-old, detached twig pieces. Bacterial spot (BS)-sensitive cultivar 'O'Henry' was most susceptible to B. obtusa compared with BS-sensitive 'Summerprince', brown rot (BR)-resistant 'Contender', and BR-sensitive 'Coronet' but was least susceptible to L. persoonii. Coronet was most susceptible to L. persoonii. There were no significant differences between susceptibility of the cultivars to P. amygdali. This study established that L. persoonii is currently the most frequent twig blight pathogen in South Carolina, perhaps owing to its superior fitness. Some fungicides were effective in controlling all twig blight pathogens and may therefore be useful for chemical management strategies. Our study also provides the first evidence that the genetic basis of resistance to BS and BR in peach trees is not necessarily linked to tolerance to wood pathogens.

First Report of Leaf Spot Caused by Pseudocercospora sp. on Lonicera vidalii in Korea

Lonicera vidalii Franch. & Sav. (family Caprifoliaceae) is a native tree in Korea and Japan. It is a rare deciduous tree of the forest community, mainly occurring in the southern part of Korea. In September 2017, leaf spots on trees, typical symptoms caused by cercosporoid fungi, were observed in Hongneung Arboretum, Seoul, Korea (37°35′37″N, 127°02′38″E). Initial symptoms presented as orbicular to irregular, pale- to dark-brown leaf spots typically 0.2 to 0.9 cm in diameter, which in some cases merged to form larger blotches across the surface of mature leaves. At infection sites, septate, branched, hyaline to pale brown, smooth, and 2 to 2.5 μm wide hyphae of the fungus were seen emerging through the stomata at the adaxial leaf side. Stromata were large and well-developed, globular, olivaceous brown, 30 to 50 µm in diameter, and emerging through stomatal openings. Conidiophores were aggregated in loose to dense fascicles through stomatal openings, subcylindrical, proliferating sympodially, straight to slightly geniculate, one- to four-septate, 15 to 53 × 3.5 to 5.5 μm, and smooth. Conidiogenous cells were terminal, cylindrical, proliferating sympodially, and 12.5 to 27 × 3.5 to 5.5 μm. Conidia were solitary, guttulate cylindrical to narrowly obclavate, straight to mildly curved, obtuse to rounded at the apex, one- to four-septate, variable in length, and 19 to 97 × 2 to 4 μm. Three monoconidial isolates were deposited in the culture collection (CDH) of the National Institute of Forest Science, Korea (CDH2017-15 to CDH2017-17). To ensure the identity of the fungus, genomic DNA was extracted, and sequence comparisons were made based on the partial nucleotide sequences of internal transcribed spacer (ITS) rDNA, translation elongation factor-1 alpha (EF-1α), actin, and RNA polymerase II second largest subunit (rpb2), using the respective primer pairs ITS1/ITS4, EF1-728F/EF1-986R, ACT-512F/ACT-783R, and RPB2-5f2/fRPB2-7cR (Nakashima et al. 2016). The sequences obtained were deposited in GenBank (MG712852 to MG712854, MG712861 to MG712863, MG712858 to MG712860, and MG930772 to MG930774, respectively). For a phylogenetic analysis, sequences from different gene regions (ITS, EF-1α, actin, and rpb2) obtained from GenBank were aligned, concatenated, and analyzed as a single dataset based on a maximum likelihood analysis. This Korean cercosporoid fungus was positioned in a clearly distinct lineage, provisionally representing an undetermined species of Pseudocercospora, which is closest to Pseudocercospora stephanandrae (Tak. Kobay. & H. Horie) C. Nakash. & Tak. Kobay., MUCC 914 (NR 111469 in ITS, GU384526 in EF-1α, GU320516 in actin, and KX462658 in rpb2). Sequence comparisons revealed that this Korean pathogen differed from P. stephanandrae at 4 of 477 characters (∼1.0%) in the ITS, 3 of 294 (∼1.0%) in the EF-1α, 4 of 190 (∼2.1%) in the actin, and 43 of 686 (∼6.3%) in the rpb2 sequences. In addition, this Korean pathogen is morphologically distinct from P. stephanandrae by having larger stromata as well as longer conidiophores and conidial size (Nakashima and Kobayashi 2000). Based on morphology and molecular analyses, the fungus was tentatively identified as Pseudocercospora sp. (Guo and Hsieh 1995; Nakashima et al. 2016). Pathogenicity was demonstrated by hyphal suspensions from 15-day-old cultures onto leaflets of L. vidalii and then maintaining them in a growth chamber (22°C and 80% relative humidity). Controls were treated with sterile water. Distinct leaf spot symptoms on the inoculated leaflets were developed, and the controls remained symptomless. The pathogen, recovered from symptomatic leaflets, was morphologically identical to those observed in the field. Lonicera-Pseudocercospora associations were recorded in China, Japan, Taiwan, Korea, New Zealand, and Brazil. However, the leaf spot infection associated with Pseudocercospora sp. on L. vidalii has not been recorded worldwide (Farr and Rossman 2017). This is the first report of leaf spot caused by Pseudocercospora sp. on L. vidalii globally as well as in Korea. The disease poses a threat to ornamental plantings and naturally growing plants of Lonicera spp. in Korea.

First Report of Botrytis pelargonii Causing Postharvest Gray Mold on Fresh Ginseng Roots in China

Chinese ginseng (Panax ginseng) is a perennial Chinese herb of the Araliaceae family. It is found in the three northeast provinces of China. As a valuable restorative tonic, it is widely used in traditional Chinese medicine (Radad et al. 2006). In November 2015 and 2016, gray mold was observed on 10 to 35% of fresh ginseng roots in two storage facilities under complete darkness at 4°C in Ji An and Fu Song City, Jilin Province. Initial symptoms included light brown, water-soaked lesions on ginseng roots. Within 30 days, the diseased areas enlarged, with dense, abundant gray mycelia forming on lesions. To isolate the pathogen, small pieces of diseased roots were surface disinfested in 3% NaClO for 2 min, rinsed twice in distilled water, plated on potato dextrose agar (PDA), and incubated at 22°C for 5 days. Sixteen isolates were recovered by single-spore isolation. Colony morphology was almost identical among all isolates. Representative isolate PG-S015 was grown on PDA under constant fluorescent light at 22°C. After 5 days, abundant mycelia with branched conidiophores were produced. Conidia were single, aseptate, pale brown, and globose to subglobose. Conidial size ranged from 8.2 to 17.3 μm in length and from 5.8 to 12.2 μm in width, averaging 13.6 ± 0.6 × 8.7 ± 0.3 μm (n = 50). The conidia were slightly longer than B. cinerea (Zhang et al. 2006). After 9 days, black, scattered, irregular sclerotia were produced. Sclerotial size measured 1.0 to 3.0 × 1.3 to 6.0 mm with the average of 2.1 × 3.8 mm (n = 50). DNA was extracted from all isolates. All 16 isolates were sequenced for the rDNA internal transcribed spacer (ITS), glyceraldehyde-3-phosphate dehydrogenase (G3PDH), DNA-dependent RNA polymerase subunit II (RPB2), and heat-shock protein 60 (HSP60) genetic markers. Their ITS sequences (KY810515 to KY810530) were identical to those of B. pelargonii (AJ716290) and B. cinerea (KY319171). The G3PDH (KY827182 to KY827197) and HSP60 (KY827198 to KY827213) sequences were 137 and 42 bp shorter than those of B. cinerea (GenBank KY275256 and KX229753) and identical to those of B. pelargonii (AJ704990 and AJ716046). The RPB2 sequences (KY827214 to KY827229) were also 99% identical to that of B. pelargonii (AJ745662). The fungus was identified as B. pelargonii based on its morphological and molecular characteristics (Staats et al. 2005; Zhang et al. 2006). Pathogenicity tests were performed by pipetting a 100 μl of conidial suspension (1 × 10⁵ conidia/ml) of each selected isolate PG-S015 and PG-S-FS-017 onto a 5-year-old fresh ginseng root, three replicates per isolate. Sterilized water was used as the noninoculated control treatment. The experiment was carried out three times. All inoculated roots were maintained at 4°C and 90% relative humidity, similar to the environmental conditions in which the disease was observed. Within 30 days, all inoculated ginseng roots developed similar symptoms to those of the naturally occurring disease described above, whereas all noninoculated roots remained healthy. Isolates with identical morphological and molecular characteristics were recovered from the diseased roots. Prior to this report, B. pelargonii was exclusively recovered from Pelargonium spp. (Strider 1985). This is the first report of B. pelargonii causing postharvest gray mold on stored fresh ginseng roots. Proper management should be taken to reduce the losses from this disease to the quality and marketability of ginseng as a highly valuable traditional Chinese medicine.

Trichoderma pseudokoningii identified based on morphology was re-identified as T. longibrachiatum through molecular characterization

Trichoderma pseudokoningii and T. longibrachiatum have many morphological similarities viz,diffusion of yellow pigment through the agar, sparsely branched conidiophores having a high proportion of solitary phialides; size and shape of phialides, shape and colour of conidia and presence of chlamydospores with minute differences in conidiation and size of conidia. Due to the overlapping characters, the morphology alone is not sufficient in differentiating these two species, therefore Internal Transcribed Spacer (ITS) region and Translation Elongation Factor 1 alpha (tef1) gene were used to confirm identification of T. pseudokoningii and T. longibrachiatum. Thirty two isolates of Trichoderma species were collected from different parts of India and identified as T. pseudokoningii (17 isolates) and T. longibrachiatum (15 isolates) based on morphology. But all the 17 T. pseudokoningii isolates have been proved as T. longibrachiatum through ITS region and tef1 gene sequence analysis. Apart from the NCBI-BLAST, these Indian T. pseudokoningii isolates were confirmed as T. longibrachiatum also through Trichokey and TrichoBLAST. There is only one Indian accession (ITS sequence) available in NCBI database in the name of T. pseudokoningii (JX500737) from Mizoram state, but it is also not proved to be T. pseudokoningii, when it was analysed through Trichokey (showed as T.effusum) and TrichoBLAST (T. citrinoviride). The present analysis confirmed that Trichoderma isolates identified as T. pseudokoningii in India are truly T. longibrachiatum.

Molecular heterozygosity and genetic exploitations of Trichoderma inter-fusants enhancing tolerance to fungicides and mycoparasitism against Sclerotium rolfsii Sacc.

Protoplast fusion is an imperative tool to develop Trichoderma inter-fusants having desire traits through genetic manipulation. Study designed to develop diverse Trichoderma fusants for fungicide tolerance (Mancozeb, Thiram, Tebuconazole, and Carbendazim) and enhanced mycoparasitic activity against Sclerotium rolfsii sacc. The mycoparasitic T. virens NBAII Tvs12 and fungicide tolerant T. koningii MTCC 796 were utilized for protoplast fusion. The derived inter-fusants were subjected to diploidization using d-camphor in minimal media followed by successive three sub culturing onto potato dextrose agar to obtain 36 stable fusants. The stable fusants were employed for conidial size, fungicide tolerance, mycoparasitism, gene specific SSR amplification and molecular heterozygosity analysis. The results explained that 22 homozygous mutants illustrated characteristic of either one parental strain and 14 heterozygous recombinants depicted traits of both parental strains. The antagonistic activity of fusants against S. rolfsii depicted highest growth inhibition (87.91%) by potent inter-fusant (Fu 21) with improved fungicide tolerance capacity. The molecular study revealed highest observed heterozygocity (0.544), coefficient of gene differentiation (0.526) and gene flow (0.387) by Fu 21 indicating better genetic exploitation of parental strains into that fusant with good genetic purity. Principal coordinate analysis of fusants and parental strains exhibited 65.07% total variation and confirmed the scattering pattern matched with UPGMA clustering pattern. The stable heterozygous Fu 21 derived from inter-fusion between Tvs 12 and MTCC 796 might be useful to practice eco-friendly bioformulation tolerance to fungicides for effective integrated stem rot disease management in groundnut.

Canker disease caused by Chrysoporthe doradensis and C. cubensis on Eucalyptus sp. and Tibouchina spp. in Brazil

Chrysoporthe species are known to cause canker on hosts belonging to Myrtaceae and Melastomataceae families. Cankers occur on tree trunks and branches and may reduce growth and lead to plant death. In this study, the incidence and pathogenicity of Chrysoporthe cubensis and other species causing canker on Eucalyptus sp., Tibouchina heteromalla and T. granulosa were examined. The isolates were collected in Maranhao (MA) and Minas Gerais (MG) in Brazil. Sequence analysis of beta-tubulin and actin genomic regions confirmed the presence of C. cubensis and C. doradensis on clones of the hybrid Eucalyptus grandis x E. urophylla, T. granulosa, and T. heteromalla in Brazil. Morphological characterization enabled the identification of the isolates from both genera primarily based on differences in conidial size and shape. The isolates were pathogenic to ten Eucalyptus clones and Tibouchina plants. Our results contribute new knowledge of Chrysoporthe species causing diseases of woody plants in Brazil of importance to Eucalyptus breeding programs when screening for resistance. Furthermore, this is the first report of C. doradensis infecting Eucalyptus and T. granulosa, as well as the first record of C. cubensis infecting T. heteromalla in Brazil.

Gray mold disease of Paris polyphylla var. yunnanensis and its pathogen identification

Gray mold disease is one of the most important diseases of planted Paris polyphylla var. yunnanensis, the disease appeared primarily as blossom blights and fruit rots, but also as stem rots, leaf rots.In this study, the pathogenetic fungi was isolated from plant tissue or sclerotia that covering the fruit of diseased P. polyphylla var. yunnanensis, the pathogen was certified according to Koch's Postulation. The pathogen produced abundant black, irregular sclerotia on surface of diseased plants and potato dextrose agar. The conidiophores and clusters of oval conidia resembled a grape-like cluster, the size of conidia was 9.70-13.70 μm [average of (11.32±0.82)μm]×7.05-9.12 μm [average of (8.24±0.48)μm], the microconidia produced on potato dextrose agar were spherical,and the size was （3.34±0.31） μm,the pathogen was identified as Botrytis sp based on morphological characteristics. The DNA sequence analysis of the G3PDH, HSP60, RPB2 genes placed the pathogen in a single clade that outside defined species of Botrytis, so the pathogen could be identified as a new species of Botrytis. The pathogen requires 20 °C, pH 8, darkness or low light condition for the best growth.

Characterization and pathogenicity of sweet potato (Ipomoea batatas) black rot caused by Ceratocystis fimbriata in Korea

Black rot disease was observed in sweet potato in Korea during a disease monitoring survey in 2017. The symptoms were black, small, circular, and slightly sunken lesions in the initial stages, leading to enlarged black spots and perithecia with long necks that appeared as dark bristles in the later stages. The causative agent was isolated on potato dextrose agar (PDA) and stored at the Sweet Potato Research Laboratory, Bioenergy Crop Research Institute, RDA, Muan (SPL17100 and SPL17101). The cultured organism produced cylindrical single-celled conidia after 5 days of incubation at 25 °C with a conidial size of 8.5–65.2 × 2.6–7.3 μm. Brownish, globose, and thick-walled aleuroconidia were produced with an 11.9–17.0 × 8.3–12.2 μm size. The perithecia were globose and dark brown with long thin necks tapering from the base to the apex. Morphologically, the fungus was identified as Ceratocystis fimbriata, which was well supported by the combined phylogenetic analysis of the sequences of the internal transcribed spacer (ITS), large subunit (LSU), and elongation factor 1-α (EF-1α) genes. Pathogenicity tests were conducted, and Koch’s postulates were confirmed.

Studies of botryosphaerialean fungi associated with canker and dieback of tree hosts in Dongling Mountain of China

Botryosphaeriales is an order comprising of latent fungal pathogens with a wide range of woody hosts. These pathogens represent interesting and diverse fungi with a confusing taxonomy due to their similar morphological characters. Many genera or families of this order have not been robustly sampled or systematically studied in separate hosts and regions, although recent studies have made enormous progress. In this study, five species of Aplosporellaceae and Botryosphaeriaceae were isolated from Juglans regia (Juglandaceae), Rhus typhina (Anacardiaceae) and Ziziphus jujuba (Rhamnaceae) in Dongling Mountain of China. These species include Aplosporella ginkgonis, Aplosporella javeedii, Botryosphaeria dothidea, Phaeobotryon rhoinum sp. nov. and Phaeobotryon rhois. Of which, Aplosporella javeedii and A. ginkgonis were identified as the first records from Ziziphus jujube and Rhus typhina, respectively. Phaeobotryon rhoinum is characterised by its globose, scattered to gregarious pycnidia with ellipsoid to oblong, brown, 1-septate conidia. It can be distinguished from the similar species P. cercidis, P. cupressi, P. mamane, P. quercicola and P. rhois based on host association and conidial size and colour. The results represent the first attempts to study Aplosporella, Botryosphaeria and Phaeobotryon with descriptions and multi-locus phylogenies (ITS, LSU and TEF-1α) in Dongling Mountain of 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.

Colletotrichum fructicola, a Member of Colletotrichum gloeosporioides sensu lato, is the Causal Agent of Anthracnose and Soft Rot in Avocado Fruits cv. “Hass”

The filamentous Ascomycota Colletotrichum gloeosporioides sensu lato is a fungus that has been reported worldwide as a causal agent of anthracnose disease in avocado and other crops. In Mexico, this species affects fruits from an early stage of development in the orchard until the post-harvest stage. Although fungicides are continuously applied to control Colletotrichum species, pericarp cankers and soft rot mesocarp in fruits are still frequently observed. Considering the lack of a precise description of the causative agent, the aim of the current study was to determine the pathogens involved in this symptomatology. Twenty-four isolates were consistently obtained from the pericarp of avocado fruits cv. “Hass” collected in the central avocado-producing area of Mexico. Morphological features such as colony growth, conidia size, and mycelial appressorium were assessed. Bayesian multilocus phylogenetic analyses were performed using amplified sequences of the internal transcribed spacer region of the nuclear ribosomal DNA; actin, chitin synthase, glyceraldehyde-3-phosphate dehydrogenase partial genes; and APn2-Mat1-2 intergenic spacer and mating type Mat1-2 partial gene from the nine selected isolates. In addition, fruits were inoculated with a conidial suspension and reproducible symptoms confirmed the presence of Colletotrichum fructicola in this area. This pathogenic species can now be added to those previously reported in the country, such as C. acutatum, C. boninense, C. godetiae, C. gloeosporioides, and C. karstii. Disease management programs to reduce the incidence of anthracnose should include C. fructicola to determine its response to fungicides that are routinely applied, considering that the appearance of new species is affecting the commercial quality of the fruits and shifting the original population structure.

Identification of Aspergillus tubingensis in a primary skin infection

ObjectiveAspergillus section Nigri comprises a group of related species that include Aspergillus niger, A. welwitschiae, A. carbonarius, A. brasiliensis and A. tubingensis. Some of these species are morphologically very similar to A. niger but exhibit different patterns of susceptibility to antifungal agents; such is the case for A. tubingensis. Therefore, when diagnosing aspergillosis, it is important to identify the pathogen at the species level. This study aimed to identify the species of an Aspergillus spp. isolate (MM-82) obtained from a patient with a dermatosis localized to the right leg. Materials and methodsThe MM-82 isolate was examined for macro- and microscopic morphology, conidia size and thermotolerance, and a phylogenetic analysis of a benA gene segment was performed for molecular identification. Susceptibility to antifungals was determined using antifungal microdilution according to the methodology of European Society of Clinical Microbiology and Infectious Diseases (EUCAST). ResultsBased on its phenotypic characteristics and the phylogenetic analysis of the sequence of a benA gene segment, the MM-82 isolate was identified as A. tubingensis. This fungus did not show resistance to antifungal agents commonly used for treatment. ConclusionThis study demonstrated that A. tubingensis can cause skin infection; this constitutes the first report of a case of aspergillosis caused by A. tubingensis in Mexico.

ISOLATION AND CHARACTERIZATION OF CHEMICAL COMPOUNDS FROM FRUIT PULP OF CASSIA FISTULA AND THEIR ANTIMICROBIAL ACTIVITY

In the present study effect of chloroform fraction of Cassia fistula fruit pulp on cyto-morphological parameters like mycelium width and conidial size of Alternaria solani has been studied. Column chromatography of chloroform extract and TLC fingerprinting of column fractions were also done. Column fractions were screened for antifungal activity and fraction showing best activity was further subjected to GC MS analysis for the purification and identification of the structure of active compound. Result suggested that mycelium width of Alternaria solani increased up to 77.89% and conidia size of the was reduced up to 97.61% at 1.25 mg/ml (Sub MIC) concentration of the chloroform extract. Eight fractions obtained from column chromatography and fraction no. 2 (FPF-2) showed maximum inhibition i.e. 98.25% against Alternaria solani. Rf values of TLC bands of column fractions were found between the range from 0.60 to 0.97cm. Â GC-MS analysis reveals the presence of butanoic acid, 2-methyl-, Penthiophane (2H-Thiopyran, tetrahydro) and Isopropyl acetate (Acetic acid, 1-methyl ethyl ester). These three compounds are responsible for the antimicrobial activity of Cassia fistula fruit pulp. Keywords: Column chromatography, cytomorphology, Gas chromatography/mass spectrometry, Alternaria solani, Cassia fistula