Anthracnose of <Emphasis Type="Italic">Polygonatum falcatum</Emphasis> caused by <Emphasis Type="Italic">Colletotrichum dematium</Emphasis>

Severe spotting, blight and drop of leaves caused by Colletotrichum dematium were found on potted plants of Polygonatum falcatum, a liliaceous ornamental, in open fields in Kagawa Prefecture, Japan, in May 2001. This new disease was named anthracnose of P. falcatum. Keisuke Tomioka, Jouji Moriwaki, Toyozo Sato contributed equally to this work. The fungal isolate and its nucleotide sequence data obtained in this study were deposited in Genebank, National Institute of Agrobiological Sciences and the DDBJ/EMBL/GenBank databases under accessions MAFF239500 and AB334523, respectively.     

Anthracnose of snapdragon caused by <Emphasis Type="Italic">Colletotrichum destructivum</Emphasis>

Severe spotting and blight of leaves caused by Colletotrichum destructivum were found on snapdragon (Antirrhinum majus L.), a scrophulariaceous ornamental, in open fields in Shizuoka Prefecture, Japan, from June through September 2004. The fungus is added to the group of the pathogens causing anthracnose of snapdragon.     

Anthracnose of <Emphasis Type="Italic">Enkianthus campanulatus</Emphasis> and <Emphasis Type="Italic">Rhynchosia acuminatifolia</Emphasis> caused by <Emphasis Type="Italic">Colletotrichum gloeosporioides</Emphasis> (new occurrence)

In 2003–2004, anthracnoses of Enkianthus campanulatus and Rhynchosia acuminatifolia were found for the first time in Kanagawa Prefecture and Tokyo in Japan. These pathogens were identified as Colletotrichum gloeosporioides based on their pathogenicity, morphology and ribosomal DNA spacer sequences. Results were presented at the annual meeting of The Phytopathological Society of Japan in 2004.     

Anthracnose of three-leaf akebia (<Emphasis Type="Italic">Akebia trifoliata</Emphasis> Koidzumi) caused by <Emphasis Type="Italic">Colletotrichum acutatum</Emphasis>

In October 2001, anthracnose caused by Colletotrichum acutatum Simmonds ex Simmonds was found on three-leaf akebia (Akebia trifoliata) in Saitama, Japan. This is the first report of anthracnose on three-leaf akebia caused by C. acutatum.     

Pythium rot of figmarigold (<Emphasis Type="Italic">Lampranthus spectabile</Emphasis>) caused by <Emphasis Type="Italic">Pythium aphanidermatum</Emphasis>

A new leaf rot disease was found on the leaves of figmarigold (Lampranthus spectabile). The causal organism, identified as Pythium aphanidermatum was found to cause the same symptoms after artificial inoculation and was then reisolated from the inoculated plants. We propose to name the disease Pythium rot of figmarigold.     

Cutting rot of chrysanthemum (<Emphasis Type="Italic">Chrysanthemum morifolium</Emphasis>) caused by <Emphasis Type="Italic">Plectosporium tabacinum</Emphasis>

Cutting rot of chrysanthemum was found on cuttings of cv. Jimba No.2 in 2008. The cuttings were imported, then transplanted in Aichi Prefecture. Root development was not initiated in about 30% of the cuttings. The cut stem ends developed black discolouration and decay. When healthy cuttings were the fungus isolated from diseased cuttings, these cuttings developed the same disease symptoms. The characteristics and morphology of the fungal culture were identical to those of Plectosporium tabacinum. We propose that the new disease be named cutting rot of chrysanthemum.     

Anthracnose of belmore sentry palm (<Emphasis Type="Italic">Howea belmoreana</Emphasis> Becc.) caused by <Emphasis Type="Italic">Colletotrichum gloeosporioides</Emphasis> (Penzig) Penzig et Saccardo

Severe leaf spots were found on the ornamental plant, belmore sentry palm (Howea belmoreana), grown in pots in a greenhouse in Ibusuki, Kagoshima, Japan in 2006. The isolated fungus caused the same symptoms after artificial inoculation and was identified morphologically and molecularly as Colletotrichum gloeosporioides. In this first report of the disease, the name anthracnose of belmore sentry palm (kenchayashi-tanso-byo in Japanese) is proposed.     

First report of blueberry red ringspot disease caused by <Emphasis Type="Italic">Blueberry</Emphasis><Emphasis Type="Italic">red</Emphasis><Emphasis Type="Italic">ringspot</Emphasis><Emphasis Type="Italic">virus</Emphasis> in Japan

Virus-like symptoms—red ringspots on stems and leaves, circular blotches or pale spots on fruit—were found on commercial highbush blueberry (Vaccinium corymbosum) cultivars Blueray, Weymouth, Duke and Sierra in Japan. In PCR testing, single DNA fragments were amplified from total nucleic acid samples of the diseased blueberry bushes using primers specific to Blueberry red ringspot virus (BRRV). Sequencing analysis of the amplified products revealed 95.7–97.7% nucleotide sequence identity with the BRRV genome. This paper is the first report of blueberry red ringspot disease caused by BRRV in Japan. The nucleotide sequence data reported in this paper are available in the GenBank/EMBL/DDBJ database as accessions AB469884 to AB469893 for BRRV isolates from Japan.     

Phytophthora blight of southern star (<Emphasis Type="Italic">Oxypetalum caeruleum</Emphasis>) caused by <Emphasis Type="Italic">Phytophthora palmivora</Emphasis> in Japan

In 2004, a damping-off symptom was found on southern star, Oxypetalum caeruleum, in Kochi Prefecture, Japan. Two Phytophthora strains with different colony patterns on potato dextrose agar were isolated, and their pathogenicity was confirmed by inoculation of southern star plants and their reisolation from symptomatic plants. Both fungi were identified as Phytophthora palmivora based on morphology, physiology, and sequence analysis of the internal transcribed spacers of nuclear ribosomal DNA. This is the first report of Phytophthora blight of southern star in the world.     

Rapid diagnosis of soybean anthracnose caused by <Emphasis Type="Italic">Colletotrichum truncatum</Emphasis> using a loop-mediated isothermal amplification (LAMP) assay

A loop-mediated isothermal amplification (LAMP) assay that directly detects Colletotrichum truncatum in diseased soybean tissues is described, thus allowing rapid diagnosis of soybean anthracnose. Using the target gene Rpb1 (that codes for the large subunit of RNA polymerase II), we designed and screened a set of species-specific primers allowing amplification at 62 °C over 70 min. After addition of SYBR Green I to the LAMP reaction products, a yellow-green color (visible to the unaided eye) developed only in the presence of C. truncatum. The detection limit of the LAMP assay was 100 pg (per μL genomic DNA). The Rpb1-Ct-LAMP assay has been successfully used to diagnose soybean anthracnose in field samples collected from Jiangsu, Anhui and Hubei provinces of China, and to detect C. truncatum in soybean seeds from farmers’ markets. Our results show that the Rpb1-Ct-LAMP assay is a useful and convenient method for detecting C. truncatum, and thus for diagnosis of soybean anthracnose.     

Anthracnose of Christmas rose caused by <Emphasis Type="Italic">Colletotrichum</Emphasis> sp.

Leaf spots were found on Christmas rose (Helleborus niger) in Yamagata Prefecture, Japan, in October 2006. The morphology of the causal fungus was very close to that of Colletotrichum truncatum. Classifying the species from the sequences of the internal transcribed spacer regions of ribosomal DNA was inconclusive, and the isolates were identified only as Colletotrichum sp. Artificial inoculation confirmed the pathogenicity of isolates to the host plant and some legumes. We propose the name anthracnose of Christmas rose for this disease by Colletotrichum sp.     

Effects of garlic (<Emphasis Type="Italic">Allium sativum</Emphasis>) juice containing allicin on <Emphasis Type="Italic">Phytophthora infestans</Emphasis> and downy mildew of cucumber caused by <Emphasis Type="Italic">Pseudoperonospora cubensis</Emphasis>

The volatile antimicrobial substance allicin (diallylthiosulphinate) is produced in garlic when the tissues are damaged and the substrate allicin (S-allyl-l-cysteine sulphoxide) mixes with the enzyme alliin-lyase (E.C.4.4.1.4). Allicin undergoes thiol-disulphide exchange reactions with free thiol groups in proteins and it is thought that this is the basis of its antimicrobial action. At 50 μg ml^-1, allicin in garlic juice inhibited the germination of sporangia and cysts and subsequent germ tube growth by Phytophthora infestans both in vitro and in vivo on the leaf surface. Disease severity in P. infestans-infected tomato seedlings was also reduced by spraying leaves with garlic juice containing allicin over the range tested (55–110 μg ml⁻¹) with an effectiveness ranging from approximately 45–100%. Similarly, in growth room experiments at concentrations from 50–1,000 μg ml⁻¹, allicin in garlic juice reduced the severity of cucumber downy mildew caused by Pseudoperonospora cubensis by approximately 50–100%. These results suggest a potential for developing preparations from garlic for use in specialised aspects of organic farming, e.g. for reducing pathogen inoculum potential and perhaps for use under glass in horticulture.     

Fusarium rot of hyacinth caused by <Emphasis Type="Italic">Gibberella zeae</Emphasis> (anamorph: <Emphasis Type="Italic">Fusarium</Emphasis><Emphasis Type="Italic"> graminearum</Emphasis>)

Severe rot of leaves, peduncles and flowers caused by Gibberella zeae (anamorph: Fusarium graminearum) was found on potted plants of hyacinth (Hyacinthus orientalis), a liliaceous ornamental, in greenhouses in Kagawa Prefecture, Japan, in January 2001. This disease was named “Fusarium rot of hyacinth” as a new disease because only the anamorph, F. graminearum, was identified on the diseased host plant. The authors contributed equally to this work. The fungal isolate and its nucleotide sequence data obtained in this study were deposited in the Genebank, National Institute of Agrobiological Sciences and the DDBJ/EMBL/GenBank databases under the accession numbers MAFF239499 and AB366161, respectively.     

First report of Choanephora rot of ice plant (<Emphasis Type="Italic">Mesembryanthemum crystallinum</Emphasis>) caused by <Emphasis Type="Italic">Choanephora cucurbitarum</Emphasis> in Japan

In summer 2007, leaf and stem rot of ice plants was found in a hydroponic greenhouse in Japan. The causal agent was a fungus identified as Choanephora cucurbitarum (Berkeley & Ravenel) Thaxter, based on pathogenicity, morphology, mating tests, and sequence analysis of the ribosomal DNA ITS region.     

Pathological studies on the southern blight of China aster (<Emphasis Type="Italic">Callistephus chinensis</Emphasis>) caused by <Emphasis Type="Italic">Sclerotium rolfsii</Emphasis>

A severe outbreak of southern blight disease of China aster was observed during the post rainy season (September–November 2015) in the Mysore and Mandya Districts of Karnataka, Southern India. The disease incidence ranged between 12 and 47%. The typical disease symptoms include water-soaked lesions on leaves, stems and on the lower stem surfaces followed by quick wilting of the whole plant with abundant production of sclerotia near the stem-soil interface. The associated fungal pathogen was isolated on potato dextrose agar (PDA) medium, on which numerous reddish-brown sclerotia were seen. A total of 26 fungal isolates were isolated and studied for the mycelial compatibility. Isolate SrCCM 1 was used for pathogenicity analysis. The results of the study showed that, there was no variation among the isolates tested. Molecular identification of the pathogen by ITS-rDNA sequences of S. rolfsii showed 100% similarity with reference sequences. Based on the cultural, morphological and molecular characteristics, the fungal pathogen was identified as Sclerotium rolfsii Sacc. (Sexual morph: Athelia rolfsii (Curzi) C.C. Tu & Kimbr). Pathogenicity tests were performed on healthy leaves, roots and stems. Typical disease symptoms on leaves, stems and roots were evident after 5, 8 and 10 days of post-inoculation. Sclerotium rolfsii is known to cause diseases in economically important crop plants. However, no reports are available on the occurrence of S. rolfsii on China aster in India.     

<Emphasis Type="Italic">Colletotrichum destructivum from</Emphasis> cowpea infecting <Emphasis Type="Italic">Arabidopsis thaliana</Emphasis> and its identity to <Emphasis Type="Italic">C. higginsianum</Emphasis>

Colletotrichum isolates isolated from cowpea in the Hangzhou area of China were identified as C. destructivum based on morphological characteristics, pathogenicity tests, sequence analysis of the internal transcribed spacer (ITS)1, 5.8S RNA gene and ITS2 regions of ribosomal DNA and the infection process. The ability of the C. destructivum isolates to infect Arabidopsis thaliana was investigated under laboratory conditions and showed a two-phase hemibiotrophic infection process. In addition, the sequences of the rDNA ITS region of C. destructivum isolates from cowpea were identical with 100% similarity to that of isolates of C. higginsianum originating from cruciferous plants. This article presents new evidence in support of C. higginsianum as a synonym of C. destructivum.     

Postharvest anthracnose on Satsuma mandarin orange caused by <Emphasis Type="Italic">Colletotrichum fioriniae</Emphasis>

In early January 2015–2017, anthracnose was detected on Satsuma mandarin orange (SMO) (Citrus unshiu) fruits kept in farmers’ storage rooms in Saga Prefecture, Japan. Three single-spore isolates from rotten fruits reproduced the postharvest anthracnose symptoms in wound-inoculated SMO fruits and were re-isolated from lesions. The isolates were identified as Colletotrichum fioriniae based on conidial morphology, culture characteristics, rDNA-ITS, and beta-tubulin-2 gene sequences. This is the first report of postharvest anthracnose on SMO caused by C. fioriniae.     

Corynespora blight of sweet pepper (<Emphasis Type="Italic">Capsicum annuum</Emphasis>) caused by <Emphasis Type="Italic">Corynespora cassiicola</Emphasis> (Berk. &; Curt.) Wei

In 2004, Corynesopra cassiicola was isolated from dark brown spots on leaves and fruits and from black blights on stems of sweet pepper plants in Kochi Prefecture, Japan. The isolated fungus was then used to inoculate sweet pepper plants and subsequently reisolated from the plants with dark brown spots and black blights, showing that C. cassiicola is a new pathogen causing Corynespora blight on sweet pepper plants. The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases as accession numbers AB366649 (TS-C11), AB366650 (TS-C21), AB366651 (TI-C32) and AB366652 (TI-C51)     

<Emphasis Type="Italic">Agrobacterium tumefaciens</Emphasis>-mediated transformation for random insertional mutagenesis in <Emphasis Type="Italic">Colletotrichum lagenarium</Emphasis>

Random insertional mutagenesis using a marker DNA fragment is an effective method for identifying fungal genes relevant to morphogenesis, metabolism, and so on. Agrobacterium tumefaciens-mediated transformation (AtMT) has long been used as a tool for the genetic modification of a wide range of plant species. Recent study has indicated that A. tumefaciens could transfer T-DNA not only to plant cells but also to fungal cells. In this study, AtMT was applied to Colletotrichum lagenarium for random insertional mutagenesis. We constructed a binary vector pBIG2RHPH2 carrying a hygromycin-resistant gene cassette between the right and left borders of T-DNA. Optimal co-cultivation of C. lagenarium wild-type 104-T with pBIG2RHPH2-introduced A. tumefaciens C58C1 led to the production of 150–300 hygromycin-resistant transformants per 10⁶ conidia. Southern blot analysis revealed that T-DNA was mainly integrated at a single site in the genome and at different sites in transformants. The T-DNA inserts showed small truncations of either end, but the hygromycin-resistant gene cassette inside the T-DNA was generally intact. The mode of T-DNA insertion described above resulted in highly efficient gene recovery from the transformants by thermal asymmetrical interlaced-polymerase chain reaction. The fungal genomic DNA segments flanking T-DNA were identified from five of eight mutants that had defective melanin biosynthesis. The sequence from one of the segments was identical to that of the melanin biosynthesis gene PKS1 of C. lagenarium, which we previously characterized. These results strongly support our notion that AtMT is a possible tool for tagging genes relevant to pathogenicity in the plant pathogenic fungus C. lagenarium.