Phytophthora Root and Collar Rot of Paulownia, a New Disease for Europe

Paulownia species are fast growing trees native to China, which are being grown in managed plantings in several European countries for the production of wood and biomasses. In 2018, wilting, stunting, leaf yellowing, and collapse, as a consequence of root and crown rot, were observed in around 40% of trees of a 2-year-old planting of Paulownia elongata × P. fortunei in Calabria (Southern Italy). Two species of Phytophthora were consistently recovered from roots, basal stem bark, and rhizosphere soil of symptomatic trees and were identified as Ph. nicotianae and Ph. palmivora on the basis of both morphological characteristics and phylogenetic analysis of rDNA ITS sequences. Koch’s postulates were fulfilled by reproducing the symptoms on potted paulownia saplings transplanted into infested soil or stem-inoculated by wounding. Both Phytophthora species were pathogenic and caused root rot and stem cankers. Even though P. palmivora was the only species recovered from roots of naturally infected plants, in pathogenicity tests through infested soil P. nicotianae was more virulent. This is the first report of Phytophthora root and crown rot of a Paulownia species in Europe. Strategies to prevent this emerging disease include the use of healthy nursery plants, choice of well-drained soils for new plantations, and proper irrigation management.

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First Confirmation of Phytophthora quercina on Oaks in Asia

Plant Disease ◽

10.1094/pdis.2002.86.4.442c ◽

2002 ◽

Vol 86 (4) ◽

pp. 442-442 ◽

Cited By ~ 5

Author(s):

Y. Balci ◽

E. Halmschlager

Keyword(s):

Growth Rate ◽

Tree Mortality ◽

Morphological Characteristics ◽

Phytophthora Species ◽

Infested Soil ◽

Mature Trees ◽

Main Trunk ◽

Soil P ◽

Phytophthora Spp ◽

Individual Trees

During surveys of forests in the Asian Region of Turkey in 1999, 2000, and 2001, mature trees of several oak species were observed to have symptoms of decline, including thinning of the crown, yellowing and wilting of leaves, dieback of branches, and growth of epicormic shoots on branches and the main trunk. Observations over time confirmed a slow progress of tree mortality. To isolate Phytophthora spp. that might be associated with the decline, samples of rhizosphere soil including fine roots with necrotic lesions, were collected from around the bases of individual trees. Young leaflets from Quercus robur, Q. petraea, and Q. hartwissiana were used in a bioassay to bait flooded soil subsamples. After 3 to 5 days, baits were transferred to plates of PARPNH, a medium selective for Phytophthora spp. (1). Phytophthora spp. were recovered from 38 of 51 sites investigated (75%). In all, 10 species of Phytophthora were isolated; P. quercina was detected most frequently and was obtained from 29 (57%) sampled sites. Identification of isolates of P. quercina was based on comparisons of cultural and morphological characteristics to the description of the holotype (2) and to authentic cultures. Slight differences from the description of the holotype were observed for the size of sporangia, oogonia, and chlamydospores. On V8 agar most of the colonies showed an optimal radial growth at 22.5°C, with a growth rate ranging from 4.5 to 5.6 mm per day. Isolates from Turkey showed a lower optimal temperature and a higher growth rate compared with European strains. Recent studies have shown that many Phytophthora species, including P. quercina, occur in declining oak stands in Europe. In pathogenicity tests of infested soil, P. quercina isolates proved to be one of the more pathogenic species to roots of young Q. robur plants (2). Previously, P. quercina was only found in Europe. New hosts species for P. quercina include Q. hartwissiana, Q. frainetto, and the endemic species Q. vulcanica. Observations suggest that P. quercina is widespread in Turkey and occurs within the natural range of oak, which raises the question of the role of P. quercina in the oak decline syndrome. References: (1) T. Jung et al. Eur. J. For. Pathol. 26:253, 1996. (2) T. Jung et al. Mycol. Res. 103:785, 1999.

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PhytophthoraSpecies Are Common on Nursery Stock Grown for Restoration and Revegetation Purposes in California

Plant Disease ◽

10.1094/pdis-01-18-0167-re ◽

2019 ◽

Vol 103 (3) ◽

pp. 448-455 ◽

Cited By ~ 5

Author(s):

S. Rooney-Latham ◽

C. L. Blomquist ◽

K. L. Kosta ◽

Y. Y. Gou ◽

P. W. Woods

Keyword(s):

North America ◽

Phytophthora Species ◽

Molecular Techniques ◽

Crown Rot ◽

Native Plant ◽

Nursery Stock ◽

Plant Nursery ◽

Root And Crown Rot ◽

Symptomatic Tissue ◽

First Time

Phytophthora tentaculata was detected for the first time in North America in 2012 in a nursery on sticky monkeyflower plant (Diplacus aurantiacus) and again in 2014 on outplanted native plants. At that time, this species was listed as a federally actionable and reportable pathogen by the USDA. As a result of these detections, California native plant nurseries were surveyed to determine the prevalence of Phytophthora species on native plant nursery stock. A total of 402 samples were collected from 26 different native plant nurseries in California between 2014 and 2016. Sampling focused on plants with symptoms of root and crown rot. Symptomatic tissue was collected and tested by immunoassay, culture, and molecular techniques (PCR). Identifications were made using sequences from the internal transcribed spacer (ITS) rDNA region, a portion of the trnM-trnP-trnM, or the atp9-nad9 mitochondrial regions. Phytophthora was confirmed from 149 of the 402 samples (37%), and from plants in 22 different host families. P. tentaculata was the most frequently detected species in our survey, followed by P. cactorum and members of the P. cryptogea complex. Other species include P. cambivora, P. cinnamomi, P. citricola, P. hedraiandra, P. megasperma, P. multivora, P. nicotianae, P. niederhauserii, P. parvispora, P. pini, P. plurivora, and P. riparia. A few Phytophthora sequences generated from mitochondrial regions could not be assigned to a species. Although this survey was limited to a relatively small number of California native plant nurseries, Phytophthora species were detected from three quarters of them (77%). In addition to sticky monkeyflower, P. tentaculata was detected from seven other hosts, expanding the number of associated hosts. During this survey, P. parvispora was detected for the first time in North America from symptomatic crowns and roots of the nonnative Mexican orange blossom (Choisya ternata). Pathogenicity of P. parvispora and P. nicotianae was confirmed on this host. These findings document the widespread occurrence of Phytophthora spp. in native plant nurseries and highlight the potential risks associated with outplanting infested nursery-grown stock into residential gardens and wildlands.

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Morphological and molecular characterization of Phytophthora species associated with root and crown rot of pomegranate in Iran

Plant Pathology ◽

10.1111/ppa.13320 ◽

2020 ◽

Author(s):

Fariba Ghaderi ◽

Azadeh Habibi

Keyword(s):

Molecular Characterization ◽

Phytophthora Species ◽

Crown Rot ◽

Root And Crown Rot ◽

Morphological And Molecular Characterization

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Influence of Chloride and Nitrogen Form on Rhizoctonia Root and Crown Rot of Table Beets

Plant Disease ◽

10.1094/pdis.1997.81.6.635 ◽

1997 ◽

Vol 81 (6) ◽

pp. 635-640 ◽

Cited By ~ 20

Author(s):

Wade H. Elmer

Keyword(s):

Dry Weight ◽

Anastomosis Group ◽

Crown Rot ◽

Infested Soil ◽

Nitrogen Form ◽

Root Yield ◽

Field Soils ◽

Root And Crown Rot ◽

The Mean ◽

Group 2

The effect of NaCl combined with Ca(NO3)2 or (NH4)2SO4 was examined on table beets (Beta vulgaris) in the presence and absence of Rhizoctonia solani (anastomosis group 2-2), the cause of Rhizoctonia root and crown rot. Transplants of cvs. Detroit Dark Red and Early Wonder grown in the greenhouse in infested soils and fertilized with Ca(NO3)2 (10 mmol of N) were 32% larger in dry weight than plants treated with (NH4)2SO4 (10 mmol of N). In noninfested soils, a 17% increase in dry weights was observed for plants treated with Ca(NO3)2 compared to plants that were fed (NH4)2SO4. When NaCl (0.17 mmol) was applied, the mean dry weight sincreased 40% in noninfested soil and 12% in infested soil compared to plants that received no NaCl. No significant interaction occurred between N fertilizer and NaCl in greenhouse trials. However, in field soils infested with R. solani, NaCl (560 kg/ha) combined with (NH4)2SO4 (112kg of N per ha) produced 26 to 47% more root yield than when (NH4)2SO4 was used alone. Inthe absence of NaCl, Ca(NO3)2 suppressed disease more than (NH4)2SO4, but adding NaCl to Ca(NO3)2 did not increase yield more than Ca(NO3)2 alone. The Cl salts KCl, CaCl2, and MgCl2did not significantly differ from NaCl in their ability to increase the dry weight of beets grownin infested soils. Leaf and root analyses revealed that (NH4)2SO4 applications increased N, P, S, and Mn in tissue more than Ca(NO3)2 applications. Applying NaCl increased tissue levels of Na, Cl, and Mn more than in plants that were not fed NaCl. All of the Cl salts had the effect of increasing concentrations of Cl and Mn in the plant. There was no evidence that the Na ion was disease suppressive. Chloride, however, may be of use in disease management of Rhizoctonia root and crown rot of table beets.

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First Report of Phytophthora citrophthora on Penstemon barbatus in Italy

Plant Disease ◽

10.1094/pd-90-1260a ◽

2006 ◽

Vol 90 (9) ◽

pp. 1260-1260 ◽

Cited By ~ 1

Author(s):

A. Garibaldi ◽

D. Bertetti ◽

D. Minerdi ◽

M. L. Gullino

Keyword(s):

Its Region ◽

The United States ◽

Phytophthora Species ◽

Crown Rot ◽

Pathogenicity Test ◽

Phytophthora Citrophthora ◽

First Report ◽

Blastn Analysis ◽

Root And Crown Rot ◽

Pathogenicity Tests

Penstemon barbatus (Cav.) Roth (synonym Chelone barbata), used in parks and gardens and sometimes grown in pots, is a plant belonging to the Scrophulariaceae family. During the summers of 2004 and 2005, symptoms of a root rot were observed in some private gardens located in Biella Province (northern Italy). The first symptoms resulted in stunting, leaf discoloration followed by wilt, root and crown rot, and eventually, plant death. The diseased tissue was disinfested for 1 min in 1% NaOCl and plated on a semiselective medium for Oomycetes (4). The microorganism consistently isolated from infected tissues, grown on V8 agar at 22°C, produced hyphae with a diameter ranging from 4.7 to 5.2 μm. Sporangia were papillate, hyaline, measuring 43.3 to 54.4 × 26.7 to 27.7 μm (average 47.8 × 27.4 μm). The papilla measured from 8.8 to 10.9 μm. These characteristics were indicative of a Phytophthora species. The ITS region (internal transcribed spacer) of rDNA was amplified using primers ITS4/ITS6 (3) and sequenced. BLASTn analysis (1) of the 800 bp obtained showed a 100% homology with Phytophthora citrophthora (R. & E. Sm.) Leonian. The nucleotide sequence has been assigned GenBank Accession No. DQ384611. For pathogenicity tests, the inoculum of P. citrophthora was prepared by growing the pathogen on autoclaved wheat and hemp kernels (2:1) at 25°C for 20 days. Healthy plants of P. barbatus cv. Nano Rondo, 6 months old, were grown in 3-liter pots (one plant per pot) using a steam disinfested substrate (peat/pomix/pine bark/clay 5:2:2:1) in which 200 g of kernels per liter of substrate were mixed. Noninoculated plants served as control treatments. Three replicates were used. Plants were maintained at 15 to 20°C in a glasshouse. The first symptoms, similar to those observed in the gardens, developed 21 days after inoculation, and P. citrophthora was consistently reisolated from infected plants. Noninoculated plants remained healthy. The pathogenicity test was carried out twice with similar results. A nonspecified root and crown rot of Penstemon spp. has been reported in the United States. (2). To our knowledge, this is the first report of P. citrophthora on P. barbatus in Italy as well as in Europe. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997 (2) F. E. Brooks and D. M. Ferrin. Plant Dis. 79:212, 1995. (3) D. E. L. Cooke and J. M. Duncan. Mycol. Res. 101:667, 1997. (4) H. Masago et al. Phytopathology 67:425, 1977.

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First report of Fusarium commune causing root and crown rot on maize in Italy

Plant Disease ◽

10.1094/pdis-01-21-0075-pdn ◽

2021 ◽

Author(s):

Monica Mezzalama ◽

Vladimiro Guarnaccia ◽

Ilaria Martino ◽

Giulia Tabome ◽

Maria Lodovica GULLINO

Keyword(s):

Plant Disease ◽

Tap Water ◽

Morphological Characteristics ◽

Plant Diseases ◽

Crown Rot ◽

Conidial Suspension ◽

Fusarium Spp ◽

First Report ◽

Root And Crown Rot ◽

Pathogenicity Tests

Maize (Zea mays L.) is a cereal crop of great economic importance in Italy; production is currently of 62,587,469 t, with an area that covers 628,801 ha, concentrated in northern Italy (ISTAT 2020). Fusarium species are associated with root and crown rot causing failures in crop establishment under high soil moisture. In 2019 maize seedlings collected in a farm located in San Zenone degli Ezzelini (VI, Italy) showed root and crown rot symptoms with browning of the stem tissues, wilting of the seedling, and collapsing due to the rotting tissues at the base of the stem. The incidence of diseased plants was approximately 15%. Seedlings were cleaned thoroughly from soil residues under tap water. Portions (about 3-5 mm) of tissue from roots and crowns of the diseased plants were cut and surface disinfected with a water solution of NaClO at 0.5% for 2 minutes and rinsed in sterile H20. The tissue fragments were plated on Potato Dextrose Agar (PDA) amended with 50 mg/l of streptomycin sulfate and incubated for 48-72 hours at 25oC. Over the 80 tissue fragments plated, 5% were identified as Fusarium verticillioides, 60% as Fusarium spp., 35% developed saprophytes. Fusarium spp. isolates that showed morphological characteristics not belonging to known pathogenic species on maize were selected and used for further investigation while species belonging to F. oxysporum were discarded. Single conidia of the Fusarium spp. colonies were cultured on PDA and Carnation Leaf Agar (CLA) for pathogenicity tests, morphological and molecular identification. The colonies showed white to pink, abundant, densely floccose to fluffy aerial mycelium. Colony reverse showed light violet pigmentation, in rings on PDA. On CLA the isolates produced slightly curved macronidia with 3 septa 28.1 - 65.5 µm long and 2.8-6.3 µm wide (n=50). Microconidia were cylindrical, aseptate, 4.5 -14.0 µm long and 1.5-3.9 µm wide (n=50). Spherical clamydospores were 8.8 ± 2.5 µm size (n=30), produced singly or in pairs on the mycelium, according to the description by Skovgaard et al. (2003) for F. commune. The identity of two single-conidia strains was confirmed by sequence comparison of the translation elongation factor-1α (tef-1α), and RNA polymerase II subunit (rpb2) gene fragments (O’Donnell et al. 2010). BLASTn searches of GenBank, and Fusarium-ID database, using the partial tef-1α (MW419921, MW419922) and rpb2 (MW419923, MW419924) sequences of representative isolate DB19lug07 and DB19lug20, revealed 99% identity for tef-1α and 100% identity to F. commune NRRL 28387(AF246832, AF250560). Pathogenicity tests were carried out by suspending conidia from a 10-days old culture on PDA in sterile H2O to 5×104 CFU/ml. Fifty seeds were immersed in 50 ml of the conidial suspension of each isolate for 24 hours and in sterile water (Koch et al. 2020). The seeds were drained, dried at room temperature, and sown in trays filled with a steamed mix of white peat and perlite, 80:20 v/v, and maintained at 25°C and RH of 80-85% for 14 days with 12 hours photoperiod. Seedlings were extracted from the substrate, washed under tap water, and observed for the presence of root and crown rots like the symptoms observed on the seedlings collected in the field. Control seedlings were healthy and F. commune was reisolated from the symptomatic ones and identified by resequencing of tef-1α gene. F. commune has been already reported on maize (Xi et al. 2019) and other plant species, like soybean (Ellis et al. 2013), sugarcane (Wang et al. 2018), potato (Osawa et al. 2020), indicating that some attention must be paid in crop rotation and residue management strategies. To our knowledge this is the first report of F. commune as a pathogen of maize in Italy. References Ellis M L et al. 2013. Plant Disease, 97, doi: 10.1094/PDIS-07-12-0644-PDN. ISTAT. 2020. http://dati.istat.it/Index.aspx?QueryId=33702. Accessed December 28, 2020. Koch, E. et al. 2020. Journal of Plant Diseases and Protection. 127, 883–893 doi: 10.1007/s41348-020-00350-w O’Donnell K et al. 2010. J. Clin. Microbiol. 48:3708. https://doi.org/10.1128/JCM.00989-10 Osawa H et al. 2020. Journal of General Plant Pathology, doi.org/10.1007/s10327-020-00969-5. Skovgaard K 2003. Mycologia, 95:4, 630-636, DOI: 10.1080/15572536.2004.11833067. Wang J et al. 2018. Plant Disease, 102, doi/10.1094/PDIS-07-17-1011-PDN Xi K et al. 2019. Plant Disease, 103, doi/10.1094/PDIS-09-18-1674-PDN

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Hydnaceous fungi of China 7. Morphological and molecular characterization of Phellodon subconfluens sp. nov. from temperate, deciduous forests

Phytotaxa ◽

10.11646/phytotaxa.414.6.2 ◽

2019 ◽

Vol 414 (6) ◽

pp. 280-288 ◽

Cited By ~ 1

Author(s):

YAN-HONG MU ◽

FANG WU ◽

HAI-SHENG YUAN

Keyword(s):

New Species ◽

Morphological Characteristics ◽

Phylogenetic Position ◽

Closely Related Species ◽

Rdna Its ◽

Rdna Its Sequences ◽

Temperate Deciduous ◽

Temperate Deciduous Forests ◽

Morphological And Molecular Characterization

A new hydnaceous fungus, Phellodon subconfluens, from northeast China, is described and illustrated based on morphological characteristics and rDNA ITS sequences. The new species is characterized by circular to flabelliform basidiocarps, a greyish buff, brownish orange to reddish brown and obscurely zonate pileal surface with white, incurved margins, a monomitic hyphal system with simple-septate, generative hyphae, and broadly ellipsoid to subglobose, thin-walled basidiospores with echinulate ornamentation. Molecular analysis confirms the phylogenetic position of the new species in Phellodon. The discriminating characters of the new species and closely related species are discussed.

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Phytophthora Species Associated with Crown and Root Rot of Apple in Chile

Plant Disease ◽

10.1094/pdis.2001.85.6.603 ◽

2001 ◽

Vol 85 (6) ◽

pp. 603-606 ◽

Cited By ~ 6

Author(s):

B. A. Latorre ◽

M. E. Rioja ◽

W. F. Wilcox

Keyword(s):

Central Valley ◽

Phytophthora Species ◽

Crown Rot ◽

Apple Rootstocks ◽

Apple Trees ◽

Potting Medium ◽

Root And Crown Rot ◽

Genotype Interaction ◽

Crown And Root Rot ◽

Isolated Species

Phytophthora cactorum, P. cryptogea, P. gonapodyides, and P. megasperma were isolated from necrotic root and crown tissues or the rhizospheres of apple trees exhibiting typical symptoms of Phytophthora root and crown rot in the Central Valley of Chile. Representative isolates of all four species were pathogenic on a variety of apple rootstocks and scions in trials conducted on excised shoots and 1-year-old MM.106 rootstock grown for 4 months in infested potting medium. P. cactorum was the most frequently isolated species and the most virulent in pot tests, although a significant Phytophthora sp.-apple genotype interaction was observed. This is the first report of any species other than P. cactorum causing root and crown rot of apple trees in Chile.

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Resistance to Phytophthora Species among Rootstocks for Cultivated Prunus Species

HortScience ◽

10.21273/hortsci10391-17 ◽

2017 ◽

Vol 52 (11) ◽

pp. 1471-1476 ◽

Cited By ~ 2

Author(s):

Gregory T. Browne

Keyword(s):

Root Rot ◽

Phytophthora Species ◽

Crown Rot ◽

Phytophthora Cactorum ◽

Prunus Species ◽

Phytophthora Megasperma ◽

Soil Flooding ◽

Root And Crown Rot ◽

Crown And Root Rot ◽

Multiple Species

Many species of Phytophthora de Bary are important pathogens of cultivated Prunus L. species worldwide, often invading the trees via their rootstocks. In a series of greenhouse trials, resistance to Phytophthora was tested in new and standard rootstocks for cultivated stone fruits, including almond. Successive sets of the rootstocks, propagated as hardwood cuttings or via micropropagation, were transplanted into either noninfested potting soil or potting soil infested with Phytophthora cactorum (Lebert & Cohn) J. Schöt., Phytophthora citricola Sawada, Phytophthora megasperma Drechs, or Phytophthora niederhauserii Z.G. Abad & J.A. Abad. Soil flooding was included in all trials to facilitate pathogen infection. In some trials, soil flooding treatments were varied to examine their effects on the rootstocks in both the absence and presence of Phytophthora. Two to 3 months after transplanting, resistance to the pathogens was assessed based on the severity of root and crown rot. ‘Hansen 536’ was consistently more susceptible than ‘Lovell’, ‘Nemaguard’, ‘Atlas’, ‘Viking’, ‘Citation’, and ‘Marianna 2624’ to root and/or crown rot caused by P. cactorum, P. citricola, and P. megasperma. By contrast, susceptibility to P. niederhauserii was similarly high among all eight tested genotypes of peach, four genotypes of peach × almond, two genotypes of (almond × peach) × peach, and one genotype of plum × almond. Most plum hybrids were highly and consistently resistant to crown rot caused by P. niederhauserii, but only ‘Marianna 2624’ was highly resistant to both crown and root rot caused by all of the Phytophthora species. The results indicate that there is a broad tendency for susceptibility of peach × almond rootstocks and a broad tendency for resistance of plum hybrid rootstocks to multiple species of Phytophthora.

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First Report of Corn Kernel Brown Spot Disease Caused by Mucor irregularis in China

Plant Disease ◽

10.1094/pdis-08-14-0814-pdn ◽

2015 ◽

Vol 99 (1) ◽

pp. 159-159

Author(s):

X. D. Peng ◽

S. L. Huang ◽

S. H. Lin

Keyword(s):

Morphological Characteristics ◽

Brown Spot ◽

Corn Kernel ◽

Spot Disease ◽

Rdna Its ◽

Light Yellow ◽

Brown Spot Disease ◽

Mucor Irregularis ◽

Rdna Its Sequences ◽

Pathogenicity Tests

In October 2012, a brown spot disease was found on corn kernels during a field survey in Nanyang city (33°01′ N, 112°29′ E), China. The incidences of affected ears and kernels were 2 to 10% (n = 600) and 0.08 to 0.4% (n = 25,000), respectively. Symptoms first appeared as circular or irregular brown spots on the endosperm. These spots subsequently enlarged or coalesced, resulting in the formation of a large light-brown or light-yellow irregular speckle commonly surrounded by a dark-brown edge. Pure fungal cultures with similar morphological characteristics were obtained from surface-disinfected symptomatic kernels using a conventional method for isolation of culturable microbes. The isolated fungal cultures were purified by single-spore isolation (3). A representative isolate F1 was randomly selected, used for pathogenicity tests, and identified using morphological and molecular methods. Colonies on PDA were circular with abundant villiform aerial mycelia. The color of colonies was white-gray at first and turned to light yellow or became ochraceous after 3 days of incubation at 28°C. Hyphae were hyaline and less septate, with rectangular branches. Sporangiophores were erect and unbranched or branched, with globose sporangia formed on their tips. Sporangiospores were elliptical to round, 3.6 to 7.3 × 1.6 to 3.7 μm (n = 100) in size. Two gene regions were amplified for multilocus sequence typing. The D1/D2 region of the nuclear large subunit ribosomal RNA gene (nucLSU) was amplified with primers NL1 and NL4 and the rDNA internal transcribed spacer (ITS) with primers ITS1 and ITS4. PCR products were purified using an Axygen nucleic acid purification kit for sequencing. Both rDNA D1/D2 and rDNA-ITS sequences were submitted to GenBank with accession numbers KM093834 and KM203872, respectively. The isolate F1 showed 98% identity with two isolates of Mucor irregularis (KC524427 and KC461926) in rDNA-ITS sequences and 99% identity with multiple isolates (JX976221, JX976203, and JX976219) of M. irregularis in rDNA D1/D2 sequences. Pathogenicity tests of isolate F1 were conducted based on Koch's postulates. Thirty kernels of fresh ears (milk stage) were pricked by sterilized toothpicks and separately inoculated with a sporangiospore suspension (1 × 106 spores/ml) and 5-day-old mycelial plugs (5 × 5 mm) of isolate F1. Kernels on ears that were inoculated with sterilized water and pure PDA plugs were separately used as controls. After 7 days of incubation, brown spot symptoms developed on the F1-inoculated kernels, which were similar to those observed on the naturally infected ears from the field samples. The control ears remained symptomless during the inoculation tests. Fungal cultures showing the same morphological characteristics as those of isolate F1 were consistently recovered from the diseased cobs inoculated by isolate F1, indicating that M. irregularis was responsible for corn kernel brown spot disease. M. irregularis was reported as a pathogen causing human skin diseases in China (5), America (1), and India (2) and as a phytopathogen causing fruit rot on durian (4). This is the first report of M. irregularis causing corn kernel brown spot disease in China. References: (1) M. M. Abuali et al. J. Clin. Microbiol. 47:4176, 2009. (2) B. M. Hemashettar et al. J. Clin. Microbiol. 49:2372, 2011. (3) S. L. Huang and K. Kohmoto. Bull. Fac. Agric., Tottori Univ. 44:1, 1991. (4) W. F. Wang et al. Plant Quarant. l23:60, 2009. (5) Y. Zhao et al. Mycopathologia 168:243, 2009.

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