Corrigendum: Development of sandwich dot-ELISA for specific detection of Ochratoxin A and its application on to contaminated cereal grains originating from India

[This corrects the article DOI: 10.3389/fmicb.2015.00511.].

Fungal Planet description sheets: 1478-1549

Novel species of fungi described in this study include those from various countries as follows: Australia, Aschersonia mackerrasiae on whitefly, Cladosporium corticola on bark of Melaleuca quinquenervia, Penicillium nudgee from soil under Melaleuca quinquenervia, Pseudocercospora blackwoodiae on leaf spot of Persoonia falcata, and Pseudocercospora dalyelliae on leaf spot of Senna alata. Bolivia, Aspicilia lutzoniana on fully submersed siliceous schist in high-mountain streams, and Niesslia parviseta on the lower part and apothecial discs of Erioderma barbellatum on a twig. Brazil, Cyathus bonsai on decaying wood, Geastrum albofibrosum from moist soil with leaf litter, Laetiporus pratigiensis on a trunk of a living unknown hardwood tree species, and Scytalidium synnematicum on dead twigs of unidentified plant. Bulgaria, Amanita abscondita on sandy soil in a plantation of Quercus suber. Canada, Penicillium acericola on dead bark of Acer saccharum, and Penicillium corticola on dead bark of Acer saccharum. China, Colletotrichum qingyuanense on fruit lesion of Capsicum annuum. Denmark, Helminthosphaeria leptospora on corticioid Neohypochnicium cremicolor. Ecuador (Galapagos), Phaeosphaeria scalesiae on Scalesia sp. Finland, Inocybe jacobssonii on calcareous soils in dry forests and park habitats. France, Cortinarius rufomyrrheus on sandy soil under Pinus pinaster, and Periconia neominutissima on leaves of Poaceae. India, Coprinopsis fragilis on decaying bark of logs, Filoboletus keralensis on unidentified woody substrate, Penicillium sankaranii from soil, Physisporinus tamilnaduensis on the trunk of Azadirachta indica, and Poronia nagaraholensis on elephant dung. Iran, Neosetophoma fici on infected leaves of Ficus elastica. Israel, Cnidariophoma eilatica (incl. Cnidariophoma gen. nov.) from Stylophora pistillata. Italy, Lyophyllum obscurum on acidic soil. Namibia, Aureobasidium faidherbiae on dead leaf of Faidherbia albida, and Aureobasidium welwitschiae on dead leaves of Welwitschia mirabilis. Netherlands, Gaeumannomycella caricigena on dead culms of Carex elongata, Houtenomyces caricicola (incl. Houtenomyces gen. nov.) on culms of Carex disticha, Neodacampia ulmea (incl. Neodacampia gen. nov.) on branch of Ulmus laevis, Niesslia phragmiticola on dead standing culms of Phragmites australis, Pseudopyricularia caricicola on culms of Carex disticha, and Rhodoveronaea nieuwwulvenica on dead bamboo sticks. Norway, Arrhenia similis half-buried and moss-covered pieces of rotting wood in grass-grown path. Pakistan, Mallocybe ahmadii on soil. Poland, Beskidomyces laricis (incl. Beskidomyces gen. nov.) from resin of Larix decidua ssp. polonica, Lapidomyces epipinicola from sooty mould community on Pinus nigra, and Leptographium granulatum from a gallery of Dendroctonus micans on Picea abies. Portugal, Geoglossum azoricum on mossy areas of laurel forest areas planted with Cryptomeria japonica, and Lunasporangiospora lusitanica from a biofilm covering a biodeteriorated limestone wall. Qatar, Alternaria halotolerans from hypersaline sea water, and Alternaria qatarensis from water sample collected from hypersaline lagoon. South Africa, Alfaria thamnochorti on culm of Thamnochortus fraternus, Knufia aloeicola on Aloe gariepensis, Muriseptatomyces restionacearum (incl. Muriseptatomyces gen. nov.) on culms of Restionaceae, Neocladosporium arctotis on nest of cases of bag worm moths (Lepidoptera, Psychidae) on Arctotis auriculata, Neodevriesia scadoxi on leaves of Scadoxus puniceus, Paraloratospora schoenoplecti on stems of Schoenoplectus lacustris, Tulasnella epidendrea from the roots of Epidendrum × obrienianum, and Xenoidriella cinnamomi (incl. Xenoidriella gen. nov.) on leaf of Cinnamomum camphora. South Korea, Lemonniera fraxinea on decaying leaves of Fraxinus sp. from pond. Spain, Atheniella lauri on the bark of fallen trees of Laurus nobilis, Halocryptovalsa endophytica from surface-sterilised, asymptomatic roots of Salicornia patula, Inocybe amygdaliolens on soil in mixed forest, Inocybe pityusarum on calcareous soil in mixed forest, Inocybe roseobulbipes on acidic soils, Neonectria borealis from roots of Vitis berlandieri × Vitis rupestris, Sympoventuria eucalyptorum on leaves of Eucalyptus sp., and Tuber conchae from soil. Sweden, Inocybe bidumensis on calcareous soil. Thailand, Cordyceps sandindaengensis on Lepidoptera pupa, buried in soil, Ophiocordyceps kuchinaraiensis on Coleoptera larva, buried in soil, and Samsoniella winandae on Lepidoptera pupa, buried in soil. Taiwan region (China), Neophaeosphaeria livistonae on dead leaf of Livistona rotundifolia. Türkiye, Melanogaster anatolicus on clay loamy soils. UK, Basingstokeomyces allii (incl. Basingstokeomyces gen. nov.) on leaves of Allium schoenoprasum. Ukraine, Xenosphaeropsis corni on recently dead stem of Cornus alba. USA, Nothotrichosporon aquaticum (incl. Nothotrichosporon gen. nov.) from water, and Periconia philadelphiana from swab of coil surface. Morphological and culture characteristics for these new taxa are supported by DNA barcodes. Citation: Crous PW, Osieck ER, Shivas RG, et al. 2023. Fungal Planet description sheets: 1478-1549. Persoonia 50: 158- 310. https://doi.org/10.3767/persoonia.2023.50.05.

Fungal Planet description sheets: 1550-1613

Novel species of fungi described in this study include those from various countries as follows: Argentina, Neocamarosporium halophilum in leaf spots of Atriplex undulata. Australia, Aschersonia merianiae on scale insect (Coccoidea), Curvularia huamulaniae isolated from air, Hevansia mainiae on dead spider, Ophiocordyceps poecilometigena on Poecilometis sp. Bolivia, Lecanora menthoides on sandstone, in open semi-desert montane areas, Sticta monlueckiorum corticolous in a forest, Trichonectria epimegalosporae on apothecia of corticolous Megalospora sulphurata var. sulphurata, Trichonectria puncteliae on the thallus of Punctelia borreri. Brazil, Catenomargarita pseudocercosporicola (incl. Catenomargarita gen. nov.) hyperparasitic on Pseudocercospora fijiensis on leaves of Musa acuminata, Tulasnella restingae on protocorms and roots of Epidendrum fulgens. Bulgaria, Anthracoidea umbrosae on Carex spp. Croatia, Hymenoscyphus radicis from surface-sterilised, asymptomatic roots of Microthlaspi erraticum, Orbilia multiserpentina on wood of decorticated branches of Quercus pubescens. France, Calosporella punctatispora on dead corticated twigs of Aceropalus. French West Indies (Martinique), Eutypella lechatii on dead corticated palm stem. Germany, Arrhenia alcalinophila on loamy soil. Iceland, Cistella blauvikensis on dead grass (Poaceae). India, Fulvifomes maritimus on living Peltophorum pterocarpum, Fulvifomes natarajanii on dead wood of Prosopis juliflora, Fulvifomes subazonatus on trunk of Azadirachta indica, Macrolepiota bharadwajii on moist soil near the forest, Narcissea delicata on decaying elephant dung, Paramyrothecium indicum on living leaves of Hibiscus hispidissimus, Trichoglossum syamviswanathii on moist soil near the base of a bamboo plantation. Iran, Vacuiphoma astragalicola from stem canker of Astragalus sarcocolla. Malaysia, Neoeriomycopsis fissistigmae (incl. Neoeriomycopsidaceae fam. nov.) on leaf spots on flower Fissistigma sp. Namibia, Exophiala lichenicola lichenicolous on Acarospora cf. luederitzensis. Netherlands, Entoloma occultatum on soil, Extremus caricis on dead leaves of Carex sp., Inocybe pseudomytiliodora on loamy soil. Norway, Inocybe guldeniae on calcareous soil, Inocybe rupestroides on gravelly soil. Pakistan, Hymenagaricus brunneodiscus on soil. Philippines, Ophiocordyceps philippinensis parasitic on Asilus sp. Poland, Hawksworthiomyces ciconiae isolated from Ciconia ciconia nest, Plectosphaerella vigrensis from leaf spots on Impatiens noli-tangere, Xenoramularia epitaxicola from sooty mould community on Taxus baccata. Portugal, Inocybe dagamae on clay soil. Saudi Arabia, Diaporthe jazanensis on branches of Coffea arabica. South Africa, Alternaria moraeae on dead leaves of Moraea sp., Bonitomyces buffels-kloofinus (incl. Bonitomyces gen. nov.) on dead twigs of unknown tree, Constrictochalara koukolii on living leaves of Itea rhamnoides colonised by a Meliola sp., Cylindromonium lichenophilum on Parmelina tiliacea, Gamszarella buffelskloofina (incl. Gamszarella gen. nov.) on dead insect, Isthmosporiella africana (incl. Isthmosporiella gen. nov.) on dead twigs of unknown tree, Nothoeucasphaeria buffelskloofina (incl. Nothoeucasphaeria gen. nov.), on dead twigs of unknown tree, Nothomicrothyrium beaucarneae (incl. Nothomicrothyrium gen. nov.) on dead leaves of Beaucarnea stricta, Paramycosphaerella proteae on living leaves of Protea caffra, Querciphoma foliicola on leaf litter, Rachicladosporium conostomii on dead twigs of Conostomium natalense var. glabrum, Rhamphoriopsis synnematosa on dead twig of unknown tree, Waltergamsia mpumalanga on dead leaves of unknown tree. Spain, Amanita fulvogrisea on limestone soil, in mixed forest, Amanita herculis in open Quercus forest, Vuilleminia beltraniae on Cistus symphytifolius. Sweden, Pachyella pulchella on decaying wood on sand-silt riverbank. Thailand, Deniquelata cassiae on dead stem of Cassia fistula, Stomiopeltis thailandica on dead twigs of Magnolia champaca. Ukraine, Circinaria podoliana on natural limestone outcrops, Neonematogonum carpinicola (incl. Neonematogonum gen. nov.) on dead branches of Carpinus betulus. USA, Exophiala wilsonii water from cooling tower, Hygrophorus aesculeticola on soil in mixed forest, and Neocelosporium aereum from air in a house attic. Morphological and culture characteristics are supported by DNA barcodes. Citation: Crous PW, Costa MM, Kandemir H, et al. 2023. Fungal Planet description sheets: 1550-1613. Persoonia 51: 280-417. doi: 10.3767/persoonia.2023.51.08.

First report of Neopestalotiopsis clavispora causing cashew leaf blight disease in India

Cashew (Anacardium occidentale) is an important commercial crop and highly prone to many biotic and abiotic stress. During March 2021, severe leaf blight symptoms were observed in Priyanka variety with 25-30% incidence grown under greenhouse nursery at ICAR-Directorate of Cashew Research (ICAR-DCR), Puttur (12º74'08.92"N; 75º22'97.22"E), Karnataka. Initial symptoms include small, irregular necrotic spots and later, the spots enlarged and covered major portion of the leaf lamina. In severe infection, leaves exhibited coalescing of spots leading to blight appearance. The infected leaves were randomly collected (n=5) and surface sterilized with 1% sodium hypochlorite for 1 min followed by three washes in sterile distilled water (SDW). Samples were plated on PDA plates amended with Rifampicin (40 mg/L) and kept for incubation at 25±2 oC for 5 days (12/12 h dark light period). A white-greyish, aerial, cottony mycelium on upper side with light yellow colour on the reverse side was consistently isolated. The black viscous acervuli were observed after 10-12 days of incubation. The conidia were fusiform, five-celled, versicoloured with three olivaceous brown median cells, two terminal hyaline cells, measured 23.3±2.12 - 28.33±2.7 x 3.6±0.8 - 4.28±0.78 µm (n=30). The apical cells had two to three flexuous, unbranched appendages, and basal appendage was solitary, tubular and unbranched. Morphological and cultural characteristics confirmed the pathogen as Neopestalotiopsis sp. (Maharachchikumbura et al. 2012). Further, two representative isolates (CLB_SCN1 & CLB_SCN2) were subjected for molecular characterization selected for molecular identification based on ITS-rDNA, tef-1α and tub2 gene sequences and phylogenetic analysis. Genomic DNA was isolated from 15 days old cultures and internal transcribed spacer (ITS) of ribosomal DNA (rDNA) (White et al. 1990), translation elongation factor 1α (tef-1α) gene (O'Donnell et al. 1998) and beta tubulin (tub2) using ITS1/ITS4, TEF1/TEF2 and Bt2a/Bt2b (Carbone and Kohn 1999; Glass and Donaldson 1995) were amplified using primer pairs respectively. PCR amplicons were sequenced, and the sequences were deposited in GenBank (accession numbers: ITS: OP880881.1, OP880882.1; tef-1α: OP882579.1, OP882580.1; and tub2: OP882581., OP882582.1). The phylogeny was constructed based on combined ITS, tef-1a, and tub2 regions. Neighbour-Joining (NJ) analysis was conducted and the tree was constructed with the substitution models (branch support was evaluated by 1,000 bootstrap replications). Combined phylogeny confirmed that the sequences shared a common clade with N. clavispora. Hence, morphological, microscopic and molecular characterization confirmed the pathogen as N. clavispora. The pathogenicity test was done on six months old healthy grafts of Priyanka variety (n=9) and repeated thrice. Conidial suspension (2×106 spores/ml) of N. clavispora CLB_SCN1 (15 days old culture) was sprayed on the healthy cashew seedlings, and kept in greenhouse by covering with polythene bags for 24 h (>80 % RH) and maintained under greenhouse condition. The control grafts were inoculated with SDW. The inoculated plants showed blight symptoms after 7-10-day post inoculation and control remained heathy. Re-isolation was done from the symptomatic leaves and identity was confirmed using cultural and molecular studies. Earlier reports showed that, N. clavispora has been reported to cause cardamom leaf blight (Biju et al 2018) and leaf spot disease of plum (Banerjee and Rana 2020). To best of our knowledge, this is the first report of cashew leaf blight disease caused by N. clavispora from India (Farr and Rossman, 2022). Early detection will help farmer in better management and avoiding economic loss caused by N. clavispora.

Fungal Planet description sheets: 1436-1477

Novel species of fungi described in this study include those from various countries as follows: Argentina, Colletotrichum araujiae on leaves, stems and fruits of Araujia hortorum. Australia, Agaricus pateritonsus on soil, Curvularia fraserae on dying leaf of Bothriochloa insculpta, Curvularia millisiae from yellowing leaf tips of Cyperus aromaticus, Marasmius brunneolorobustus on well-rotted wood, Nigrospora cooperae from necrotic leaf of Heteropogon contortus, Penicillium tealii from the body of a dead spider, Pseudocercospora robertsiorum from leaf spots of Senna tora, Talaromyces atkinsoniae from gills of Marasmius crinis-equi and Zasmidium pearceae from leaf spots of Smilaxglyciphylla. Brazil, Preussia bezerrensis from air. Chile, Paraconiothyrium kelleni from the rhizosphere of Fragaria chiloensis subsp. chiloensis f. chiloensis. Finland, Inocybe udicola on soil in mixed forest with Betula pendula, Populus tremula, Picea abies and Alnus incana. France, Myrmecridium normannianum on dead culm of unidentified Poaceae. Germany, Vexillomyces fraxinicola from symptomless stem wood of Fraxinus excelsior. India, Diaporthe limoniae on infected fruit of Limonia acidissima, Didymella naikii on leaves of Cajanus cajan, and Fulvifomes mangroviensis on basal trunk of Aegiceras corniculatum. Indonesia, Penicillium ezekielii from Zea mays kernels. Namibia, Neocamarosporium calicoremae and Neocladosporium calicoremae on stems of Calicorema capitata, and Pleiochaeta adenolobi on symptomatic leaves of Adenolobus pechuelii. Netherlands, Chalara pteridii on stems of Pteridium aquilinum, Neomackenziella juncicola (incl. Neomackenziella gen. nov.) and Sporidesmiella junci from dead culms of Juncus effusus. Pakistan, Inocybe longistipitata on soil in a Quercus forest. Poland, Phytophthora viadrina from rhizosphere soil of Quercus robur, and Septoria krystynae on leaf spots of Viscum album. Portugal (Azores), Acrogenospora stellata on dead wood or bark. South Africa, Phyllactinia greyiae on leaves of Greyia sutherlandii and Punctelia anae on bark of Vachellia karroo. Spain, Anteaglonium lusitanicum on decaying wood of Prunus lusitanica subsp. lusitanica, Hawksworthiomyces riparius from fluvial sediments, Lophiostoma carabassense endophytic in roots of Limbarda crithmoides, and Tuber mohedanoi from calcareus soils. Spain (Canary Islands), Mycena laurisilvae on stumps and woody debris. Sweden, Elaphomyces geminus from soil under Quercus robur. Thailand, Lactifluus chiangraiensis on soil under Pinus merkusii, Lactifluus nakhonphanomensis and Xerocomus sisongkhramensis on soil under Dipterocarpus trees. Ukraine, Valsonectria robiniae on dead twigs of Robinia hispida. USA, Spiralomyces americanus (incl. Spiralomyces gen. nov.) from office air. Morphological and culture characteristics are supported by DNA barcodes. Citation: Tan YP, Bishop-Hurley SL, Shivas RG, et al. 2022. Fungal Planet description sheets: 1436-1477. Persoonia 49: 261-350. https://doi.org/10.3767/persoonia.2022.49.08.

First report of Nigrospora sphaerica associated with leaf spot disease of Crossandra infundibuliformis in India

Crossandra (Crossandra infundubuliformis (L.) Nees.) is one of the main floriculture crops in Karnataka. In 2020 (March-June), a characteristic leaf spot disease of unknown etiology with an incidence ranging from 10-12% (~30 ha area evaluated) was observed in Southern Karnataka (Mysore, Mandya). Initially, the symptoms developed as small specks (3 to 8 mm), characterized by circular to irregular shapes in the beginning and coalesced to form larger lesions. Ten samples were collected in polybags followed by the isolation of associated fungal pathogen on potato dextrose agar (PDA) medium amended with Chloramphenicol (60 mg/L). Briefly, small pieces of infected leaves were cut into small pieces and surface sterilized with 2% sodium hypochlorite (NaOCl) solution, rinsed three times with sterile distilled water (SDW), blot dried, then inoculated onto PDA medium, and incubated at room temperature (27 ± 2°C) for 3 - 5 days. Fungal colonies developed from the segments and were subcultured through hyphal tipping to fresh PDA plates to get pure cultures. A total of 12 pure cultures were obtained. Mycelia were initially white and eventually turned gray. The conidia were black, single-celled, smooth, spherical to subspherical, 9 to 18 μm in diameter (n=50), and borne singly on a hyaline vesicle at the tip of each conidiophore. The identity was initially established based on the cultural features and conidial morphology as Nigrospora sp. (Deepika et al., 2021). To confirm the identity of fungal isolates based on molecular sequence analysis was performed for two representative isolates (CIT1 & CIT2). ITS-rDNA, tub2 & EF-1α gene were amplified using primers ITS1/ITS4, T1/T22 & EF1-728F/986R (White et al., 1990; O'Donnel and Cigelnik, 1997; Carbone and Kohn, 1999), then purified and sequenced. The BLASTn analysis of ITS, tub2 and EF-1α gene showed 99-100% similarity with reference sequences from the GenBank database to Nigrospora sphaerica (ITS: 520bp, KX985935 - LC7312; MH854878 - CBS:166.26; tub2: 357bp, MZ032030 - WYR007, 350bp, KY019606 - LC7298, KY019522 - LC4278, KY019520 - LC4274; EF-1α: 472bp, KY019397 - LC7294, KY019331 - LC4241; MN864137 - HN-BH-3) and the sequences were deposited in GenBank (ITS: OL672271 & OL672272; tub2: OL782120 & OL782121; EF-1α: ON051604 & ON051605) (Wang et al., 2017). The associated fungal pathogen was identified as N. sphaerica (Sacc.) Mason (Chen et al. 2018; Deepika et al., 2021) based on the cultural, morphological, microscopic, and molecular characteristics. Further, pathogenicity tests were conducted on healthy plants (Crossandra cv. Arka; n=30) grown under greenhouse conditions (28±2 °C; 80% RH). Inoculations were made with conidial suspension (18 days old N. sphaerica isolate CIT1, 106 conidia/ml) prepared in SDW, and healthy plants sprayed with SDW (n=10) served as controls. All the plants were covered with polyethylene bags for 24-48 hr and observations were made at regular intervals. Typical necrotic lesions developed on 16 plants after 12 days after inoculation but no symptoms were observed on the control plants. The associated pathogen was re-isolated from diseased leaves and confirmed their identity based on morphology and cultural characteristics. Earlier, N. sphaerica was associated with various tree species as an endophyte, and recently several reports have appeared to cause disease on various crop plants (Deepika et al., 2021). However, there are no previous reports on the association of N. sphaerica causing leaf spot disease on C. infundibuliformis from India. Early diagnosis of this leaf spot disease will help the floriculturist adopt suitable management practices to avoid significant economic loss.

First report of Athelia rolfsii (=Sclerotium rolfsii) associated with foot rot disease of Chrysanthemum morifolium in India

Chrysanthemum morifolium L. is an important flower crop grown in different parts of Karnataka for its striking cut flowers and international market value. During a field survey (Mysore district, Karnataka, February, 2022), chrysanthemum fields were found infected with foot rot disease. The presence of white mycelial structures with sclerotia were recorded near the stem-soil interface. The disease incidence ranged 10-12% measured in an area of approximately 10 hectares. The infected plants showed quick wilt, yellowing and toppling of the entire plant. Infected plants from Doddamaragowdanahally and Rayanahally (n=15) were collected and associated fungal pathogen isolated after surface sterilization with NaOCl (1%) on potato dextrose agar (PDA) amended with chloramphenicol (50 mg/L). Fungal mycelia developed from the infected tissues were inoculated on to fresh PDA plates to obtained pure cultures for further identification. Fungal colonies with dense, aerial whitish-cottony mycelia with uniformly globoid sclerotia (0.284.2 mm) were observed after 15 days of incubation (28 ± 2°C). Sclerotia were white in the beginning and turned brown at maturity. The average number of sclerotia produced per plate ranged from 240 to >480 (n = 10). To further to confirm the identity of the isolates, two representative isolates (CmSr1 and CmSr2) was subjected to molecular identification based on ITS-rDNA sequences. Briefly, genomic DNA was isolated from 12 day old cultures using the CTAB method and ITS-rDNA was amplified using ITS1-ITS4 primers (White et al., 1990). An expected amplicon of >650 bp (ITS) was obtained and later sequenced from both the directions. The consensus sequences were analysed through nBLAST search which revealed that 100% sequence similarity with reference sequences of Athelia rolfsii (S. rolfsii) from GenBank database (MT127465, MN974137, KC292637; identity 656/656; 0 gaps). A phylogenetic tree obtained by the neighbor-joining method using MEGAX shared a common clade with the reference sequences retrieved and computed, thus confirming the identification based on sequence analysis and molecular phylogeny. The representative sequence of A. rolfsii isolates CmSr1 and CmSr2 isolates deposited in GenBank with Accession nos. ON456153 and ON456154, respectively. Based on etiology, morphological, cultural and molecular data the pathogen was identified as Athelia rolfsii (Curzi) Tu & Kimbrough (Syn: Sclerotium rolfsii Sacc.) (Mordue, 1974; Mahadevakumar et al., 2016, 2018). Plants (n=60) were inoculated with sclerotial bodies (2 sclerotia/plant) near stem soil interface under green house and covered with polythene bags (at 27 ± 2°C and 80% RH). Non-inoculated plants (n=20) served as controls. The development of foot rot disease was observed eight days after inoculation. A total of 48 plants showed the foot rot symptoms and 12 inoculated plants and control plants remained healthy. The identity of the fungus was confirmed by morphological and cultural characters after re-isolation. C. morifolium is an important flower crop in Karnataka. S. rolfsii is known to be associated with blight and collar rot of Chrysanthemum spp. from Kerala (Beena et al., 2002) but no species (host) identity provided. Therefore, to the best of our knowledge, this is the first report of foot rot disease caused by Athelia rolfsii on C. morifolium in India. Early diagnosis of this disease will help the farmers to adopt suitable management practices to avoid loss.

First report of Lasiodiplodia theobromae associated with panicle blight of grapes (Vitis vinifera L.) in India

Grape (Vitis vinefera L.) is a popular horticulture crop in Karnataka, India. A fungal pathogen caused panicle blight on panicles with immature fruit and severity increased subsequently in the grape growing regions of Devanahalli and Doddaballapur, Karnataka, between August and September 2019. The disease incidence varied from 15 to 18 percent in around 45 hectares of grape vineyards surveyed. The associated fungal pathogen was isolated on Potato Dextrose Agar (PDA) medium (HiMedia Laboratory, Mumbai, India) amended with Chloramphenicol. A total of 12 fungal isolates were obtained and identified based on morphology. Fungal cultures obtained from all the panicle blight affected samples were fluffy grayish to black with profuse, dense mycelium. Microscopic examinations revealed that the conidia ellipsoidal, two celled and hyaline when young, and developed dark brown pigments at maturity. Mature conidia measured 18.24±2.35 to 26.62±3.11 μm long and 10.32±1.08 to 12.57±1.82 μm width (n=30). The fungal pathogen was identified as a Lasiodiplodia sp. based on colony morphology and microscopic features. A total of three representative isolates L. theobromae (Vv12, Vv15, and Vv19) were selected for molecular identification based on ITS-rDNA, tub2 and EF-1α gene sequences and phylogenetic analysis. Genomic DNA was isolated from 12 day old cultures and ITS-rDNA, tub2 and EF-1α genes were amplified using ITS1/ITS4; Bt2a/Bt2b and EF1-728F/986R primer pairs, respectively (White et al., 1990; Glass and Donaldson, 1995, Carbone and Kohn, 1999). PCR amplicons were sequenced and the sequences were deposited in GenBank with the accession number ITS: MZ855866.1; MZ855867.1; MZ855868.1; tub2: MZ868708.1; MZ868709.1; MZ868710.1 and EF-1α: OM604750; OM604751; OM604752 respectively. The phylogeny was constructed based on combined ITS, EF-1α and the tub2 regions. Maximum Likelihood (ML) analysis was conducted and an ML tree was constructed with the substitution models (branch support was evaluated by 1,000 bootstrap replications). Combined phylogeny confirmed that the sequences shared a common clade with L. theobromae. Based on micro-morphological features and multi-locus sequence phylogeny, the associated fungal pathogen was identified as L. theobromae. There are no reports on the occurrence of L. theobromae causing panicle blight on grapes from India. Further, the pathogens association was confirmed through pathogenicity assay conducted on field harvested healthy bunches of grapes maintained under humid chamber. A total of 10 grape bunches were inoculated with a mycelial disc on the rachis of the panicle and incubated in a moist chamber for 5 days and control sets were inoculated with only agar plugs. The experiments were conducted in three replicates and repeated twice. A total of 21 panicle bunches developed typical rot symptoms 12-days post inoculation. The identity of the pathogen was confirmed based on micromorphology and cultural features after re-isolation (n=5), thus proving the Koch postulates and confirming the association of L. theobromae with panicle blight of grapes. Lasiodiplodia species are known to cause dieback, stem blight, leaf blights and spots on various crop plants. Mathur (1979) mentioned the occurrence of L. theobromae on grapes, however, no further details are available on the part associated, as well as morphological and molecular confirmation of L. theobromae. This is the first report of the L. theobromae causing panicle blight disease of grapes in India. Further, understanding the host range for L. theobromae and its variation will help to draw suitable disease management strategies.

First report of Athelia rolfsii (=Sclerotium rolfsii) causing foot rot disease of chia (Salvia hispanica L.) in India

Salvia hispanica L. (Lamiaceae) commonly called 'chia' is an important food crop that has gained significance in recent times globally due to its nutritive value. During a field survey (Mysore district, Karnataka, October, 2021), chia fields were found associated with a characteristic foot rot disease. Further, the presence of mycelial structures along with sclerotial bodies was recorded near the stem-soil interface on the infected plants. The disease incidence ranged 15-21% in an area of approximately 15 hectares of chia fields. The symptoms initially appeared as tan lesions near the stem soil interface and the lesions were colonized by the fast growing mycelium. As the disease progressed, the plants toppled due to death of the stem-root interface region. Infected plants from KM Halli (12º20'90"N; 76º37'68"E) and DMG Halli (12º28'50"N; 76º51'66"E) (n=30) were sampled and associated fungal pathogen isolated on potato dextrose agar (PDA; HiMedia Lab, Mumbai). Fungal mycelia developing from the infected tissues were inoculated on to fresh PDA plates to obtained pure cultures for further identification. Fungal colonies with dense, aerial whitish-cottony mycelia with uniformly globoid sclerotia (0.52.9 mm) were observed after 1012 days of incubation at room temperature. Sclerotia were white at first and turned brown with age. The average number of sclerotia produced per plate ranged from 150 to >280 (n = 10). To further to confirm the identity of the isolates, three representative isolates (SrSh1, SrSh5 and SrSh10) was subjected to molecular identification based on ITS-rDNA sequences. Briefly, genomic DNA was isolated from 12 day old cultures using the CTAB method and ITS-rDNA was amplified using ITS1-ITS4 primers (White et al., 1990). An expected amplicon of >650 bp was obtained and later sequenced from both the directions. The consensus sequences were analysed through nBLAST search which revealed that 100% (643/643 bp) sequence similarity with reference sequences of Athelia rolfsii (S. rolfsii) from GenBank database (KY640622 and AB075298). A phylogenetic tree obtained by the neighbor-joining method using MEGAX shared a common clade with the reference sequences retrieved and computed, thus confirming the identification based on sequence analysis and molecular phylogeny. The representative sequence of A. rolfsii isolates SrSh1, SrSh4 and SrSh7 isolates deposited in GenBank with Accession no OM021878-OM021880. Based on etiology, morphological, cultural and molecular data the pathogen was identified as Athelia rolfsii (Curzi) Tu & Kimbrough (Syn: Sclerotium rolfsii Sacc.) (Mordue, 1974; Mahadevakumar et al., 2016, 2018). Pathogenicity tests were conducted by inoculating the sclerotial bodies near stem soil interface of chia plants grown under green house (at 28 ± 2°C and 70% relative humidity). Briefly, a total of 60 healthy plants were inoculated with sclerotia and covered with polythene bags for 2 days and removed later. Plants (n=20) inoculated without any sclerotia were treated as controls. The development of characteristic foot rot disease was observed after 6-8 days post inoculation. A total of 38 plants showed the foot rot symptoms while control plants remained healthy. The identity of the fungus was confirmed by morphology and molecular sequence analysis after re-isolation. Chia is an important food crop and in recent times has been regarded as super food. Although S. rolfsii is known to be associated with many crops, this is the first report in chia. Therefore, to the best of our knowledge, this is the first report of foot rot disease caused by Sclerotium rolfsii on chia in India. Early diagnosis of this disease will help the farmers to adopt suitable management practices to avoid loss.

First report of Athelia rolfsii (=Sclerotium rolfsii) associated with southern blight disease of Macrotyloma uniflorum in India

Horse gram (Macrotyloma uniflorum (Lam.) Verdc., Fabaceae) is an important legume crop cultivated widely in the arid and semiarid regions. During a survey carried out in the Mysore district (Karnataka, India, October 2021), horse gram plants showed the symptoms of southern blight disease. Disease incidence ranged from 20-27% in the approximate 52 hectares of horse gram fields evaluated. The symptoms initiated as tan lesions and the developing mycelial threads colonized the infected root-stem interface, causing girdling; lesions on leaves enlarged and developed into distinct spots. Infected parts (leaves & stem) (n=30) were collected in poly bags and incubated in a moist chamber overnight, followed by surface sterilization of small segments of stem, leaf with 2% NaOCl, rinsed with sterile water (SW), and placed onto the potato dextrose agar (PDA, HiMedia Lab, Mumbai) supplemented with chloramphenicol (40 mg/L). The plates were incubated at room temperature (28 ± 2°C) for 5-7 days. The fungal colonies developed from the diseased segments were sub-cultured through hyphal tipping to fresh PDA plates and pure cultures were obtained. Fungal colonies with dense, aerial whitish-cottony mycelia with uniformly globoid sclerotia (0.52.9 mm) were observed after 1012 days of incubation. Sclerotia were white in the beginning and turned to brown later. The average number of sclerotia produced per plate ranged from 112 to 320 (n = 20). To determine the identity of the isolated fungal pathogen, ITS-rDNA was amplified and sequenced using ITS1/ITS4 (White et al. 1990) primers. The amplified PCR product was purified and sequenced directly. The ITS sequences (OM037658 & OM037659) shared 100% (630/643bp) sequence similarity to Athelia rolfsii (KY640622.1, AB075298). The phylogenetic tree (Neighbour-Joining method) constructed based on ITS-rDNA region confirmed that the sequences shared a common clade with reference sequence of A. rolfsii. Thus the identity was confirmed based on micromorphology and phylogenetic analysis. Pathogenicity tests were conducted on a total of 20 plants (5-6 weeks old) in greenhouse conditions (at 28 ± 2°C and 70% relative humidity) by inoculating with sclerotia from 15 days old cultures on stem and leaves and 14 plants were found infected after 5 days of post-inoculation, while uninoculated control plants remained healthy. Similarly, detached leaf assay (Mahadevakumar et al., 2018) was performed under in vitro conditions at 28 ± 2°C in a moist chamber and 28 out of 30 leaves showed the leaf spot symptoms after 3-5 days of inoculation. Uninoculated control leaves remained healthy. The identity of the fungus was confirmed by morphology and molecular analysis after re-isolation. The occurrence as a pathogen on horse gram has not been previously reported elsewhere. This is the first report of southern blight disease caused by A. rolfsii on horse gram from India. Early diagnosis of this leaf spot disease will help the farmers to adopt suitable management practices to avoid loss in production.

Cytotoxic effects of oosporein isolated from endophytic fungus Cochliobolus kusanoi

In the present study, oosporein, a fungal toxic secondary metabolite known to be a toxic agent causing chronic disorders in animals, was isolated from fungus Cochliobolus kusanoi of Nerium oleander L. Toxic effects of oosporein and the possible mechanisms of cytotoxicity as well as the role of oxidative stress in cytotoxicity to Madin-Darby canine kidney kidney cells and RAW 264.7 splene cells were evaluated in vitro. Also to know the possible in vivo toxic effects of oosporein on kidney and spleen, Balb/C mouse were treated with different concentrations of oosporein ranging from 20 to 200 μM). After 24 h of exposure histopathological observations were made to know the effects of oosporein on target organs. Oosporein induced elevated levels of reactive oxygen species (ROS) generation and high levels of malondialdehyde, loss of mitochondrial membrane potential, induced glutathione hydroxylase (GSH) production was observed in a dose depended manner. Effects oosporein on chromosomal DNA damage was assessed by Comet assay, and increase in DNA damage were observed in both the studied cell lines by increasing the oosporein concentration. Further, oosporein treatment to studied cell lines indicated significant suppression of oxidative stress related gene (Superoxide dismutase1 and Catalase ) expression, and increased levels of mRNA expression in apoptosis or oxidative stress inducing genes HSP70, Caspase3, Caspase6, and Caspase9 as measured by quantitative real time-PCR assay. Histopathological examination of oosporein treated mouse kidney and splenocytes further revealed that, oosporein treated target mouse tissues were significantly damaged with that of untreated sam control mice and these effects were in directly proportional to the the toxin dose. Results of the present study reveals that, ROS is the principle event prompting increased oosporein toxicity in studied in vivio and in vitro animal models. The high previlance of these fungi in temperate climates further warrants the need of safe food grain storage and processing practices to control the toxic effects of oosporein to humans and live stock.

Development of sandwich dot-ELISA for specific detection of Ochratoxin A and its application on to contaminated cereal grains originating from India

In the present study, generation and characterization of a highly specific monoclonal antibody (mAb) against Ochratoxin A (OTA) was undertaken. The generated mAb was further used to develop a simple, fast, and sensitive sandwich dot-ELISA (s-dot ELISA) method for detection of OTA from contaminated food grain samples. The limit of detection (LOD) of the developed enzyme-linked immunosorbent assay (ELISA) method was determined as 5.0 ng/mL of OTA. Developed method was more specific toward OTA and no cross reactivity was observed with the other tested mycotoxins such as deoxynivalenol, fumonisin B1, or aflatoxin B1. To assess the utility and reliability of the developed method, several field samples of maize, wheat and rice (n = 195) collected from different geographical regions of southern Karnataka region of India were evaluated for the OTA occurrence. Seventy two out of 195 samples (19 maize, 38 wheat, and 15 rice) were found to be contaminated by OTA by s-dot ELISA. The assay results were further co-evaluated with conventional analytical high-performance liquid chromatography (HPLC) method. Results of the s-dot ELISA are in concordance with HPLC except for three samples that were negative for OTA presence by s-dot ELISA but found positive by HPLC. Although positive by HPLC, the amount of OTA in the three samples was found to be lesser than the accepted levels (>5 μg/kg) of OTA presence in cereals. Therefore, in conclusion, the developed s-dot ELISA is a better alternative for routine cereal based food and feed analysis in diagnostic labs to check the presence of OTA over existing conventional culture based, tedious analytical methods.

Development and validation of an immunochromatographic assay for rapid detection of fumonisin B1 from cereal samples

Fumonisins are one of the most agriculturally significant environmental toxins produced by Fusarium and Aspergillus species that grow on agricultural commodities in the field or during storage. Cereals contaminated with fumonisins causes serious loss to agricultural produce leads to health problems in humans and other farm animals. In the present study, polyclonal hyperimmune sera was raised against FB1 in rabbits immunized with FB1-keyhole limpet haemocyanin (KLH). Purified antibodies were used to establish a sensitive gold nanoparticle based immunochromatographic strip (ICG) for detecting FB1 levels in cereal grains. Effective on-site detection of FB1 was achieved by developing a rapid and sensitive pAb based ICG strip. This strip had a detection limit of 5 ng mL(-1) for FB1 in cereal samples and it could be completed within 3 min. Close examination of 150 cereal samples by ICG strip method revealed that 77 were fumonisin-positive. Results obtained by the developed method was further validated with well standardized HPLC method and results of strip method was correlated well with those obtained by HPLC method. In conclusion, the developed method was a better alternative for onsite detection of FB1 in cereal samples intended for human consumption to reduce risk of humans and other farm animals. The high level of FB1 concentrations recorded in present study warrants the need to develop an awareness creation programme to the farmers of India for safe handling of cereal grains at the time of harvesting and storage of grains.