scholarly journals First Report of Alternaria alternata Causing Leaf Spots of Tea (Camellia sinensis) in China

Plant Disease ◽  
2014 ◽  
Vol 98 (5) ◽  
pp. 697-697 ◽  
Author(s):  
L. X. Zhou ◽  
W. X. Xu
Keyword(s):  
Camellia Sinensis ◽  
Alternaria Alternata ◽  
Plant Diseases ◽  
Unknown Etiology ◽  
Leaf Spot Disease ◽  
Post Inoculation ◽  
Tea Leaves ◽  
First Report ◽  
Leaf Spots ◽  
Young Leaves

Tea is the most popular non-alcoholic beverage crop in the world, which originated in China and has been cultivated in over 45 countries. In recent years, a leaf spot disease of unknown etiology has been observed on young leaves of tea trees (Camellia sinensis) grown in Luotian county, Hubei Province, China. Observed symptoms display grayish brown to white spots (about 1 cm in diameter) surrounded by brown edges. Over 20% of the young leaves were affected on surveyed trees. To identify the pathogen, six symptomatic tea leaves were collected from six individual tea trees of unknown variety in August 2012. A thin section (3 to 5 mm) of symptomatic tissue was sterilized in a bleach solution of 3% hypochlorite and placed on potato dextrose agar (PDA) medium at 25°C in darkness for isolation. Six fungal colonies displaying gray-brown and gray-white aerial mycelia were consistently recovered from lesions of the six leaves, termed as T1 to T6, respectively. Conidia produced on the colonies were olive brown, obpyriform, short conical beak at the tip, 0 to 3 vertical and 1 to 6 transverse septa, and length × width of 7.1 to 31.7 (avg. 20.1) × 2.9 to 12.7 (avg. 7.2) μm. T1 to T6 were identified as Alternaria alternata on the basis of morphological characterization, respectively (2). Confirmation of the species identification was obtained by molecular characterization of their internal transcribed spacer (ITS) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) regions amplified from the genomic DNAs using the universal primers (1). The results revealed identical sequences of ITS (GenBank Accession No. KF699530) and GAPDH among the six isolates. BLAST searches showed that they had the highest similarity with A. alternata strains, with 98.3% for ITS (AJ276055) and 96.2% for GAPDH (EF513205), deposited in fungus database ( http://www.mycobank.org/ ). Pathogenicity tests were conducted on the detached leaves expanding for 10 to 20 days of two tea varieties (cvs. Fudingdabai and Taicha No. 12) in triplicate by placing 4 mm diameter discs from 5-day-old PDA plates of T3 and T6, which were incubated in an incubator at 25°C with a 12-h photoperiod for 7 days. All inoculated leaves with or without wound treatment developed brown spots similar to the original ones at 7 days post inoculation (dpi) while the control leaves inoculated with non-colonized PDA plugs remained asymptomatic. Isolates recovered from diseased samples were of the same morphology and ITS sequence as the inoculated ones. Alternaria alternata had been described on C. sinensis in China (3), but it was only reported as a severe foliar fungal pathogen of tea in North Bengal, India (1), and to our knowledge, this is the first report of A. alternata causing leaf spots on tea leaves (C. sinensis) in China. In addition to quantity loss, the species may result in a decrease of quality of tea crop considering that it can produce Alternaria toxins related to animal and public health. The etiologic identification of the disease is expected to provide useful information for its control. References: (1) B. N. Chakraborty et al. Plant Pathol. 55:303, 2006. (2) E. G. Simmons. Page 1 in: Alternaria Biology, Plant Diseases and Metabolites. J. Chelchowski and A. Visconti, eds. Elsevier, Amsterdam, 1992. (3) F. L. Tai. Page 1527 in: Sylloge Fungorum Sinicorum. eds. Sci. Press Acad. Sin. Beijing, 1979. (4) B. S. Weir et al. Stud. Mycol. 73:115, 2012.

scholarly journals First Report of Leaf Spot Caused by Alternaria alternata on Marigold (Tagetes erecta) in Beijing, China

Plant Disease ◽  
2014 ◽  
Vol 98 (8) ◽  
pp. 1153-1153 ◽  
Author(s):  
Y. Li ◽  
J. Shen ◽  
B. H. Pan ◽  
M. X. Guo ◽  
Q. X. Wang ◽  
...  
Keyword(s):  
Alternaria Alternata ◽  
Leaf Spot ◽  
Leaf Spot Disease ◽  
Tagetes Erecta ◽  
Pathogenicity Test ◽  
First Report ◽  
Leaf Spots ◽  
Commercial Crop ◽  
Necrotic Spots ◽  
Beijing China

Marigold (Tagetes erecta) is an important commercial crop and 200 ha are planted every year in the Beijing district of China. A leaf spot disease of T. erecta was observed during 2012 and 2013 in the Beijing district. The disease was widespread, with 60 to 75% of the fields affected. Leaves of the affected plants had small, brown, necrotic spots on most of the foliage. Yield losses of flowers of up to 20 to 30% were reported. The spots gradually enlarged, becoming irregular in shape, or remained circular, and with concentric rings or zones. In the later stages of infection, the spots coalesced, and the leaves withered, dried, and fell from the plants (4). A fungus was consistently isolated on potato dextrose agar (PDA) from the infected leaves of T. erecta. After 6 days of incubation at 26°C and a 12-h photoperiod, the fungus produced colonies that were flat, with a rough upper surface (2). The conidiophores were short. Conidia varied from 18 × 6 to 47 × 15 μm and were medium to dark brown or olive-brown in color, short beaked, borne in long chains, oval and bean shaped, with 1 to 5 transverse septa and 0 to 2 longitudinal septa. The rDNA of the internal transcribed spacer regions 1 and 2 and the 5.8S gene in seven isolates were amplified using primers ITS1 (5′-TCCGTAGGTGAACCTGCGG-3′) and ITS4 (5′-TCCTCCGCTTATTGATATGC-3′). The nucleotide sequence was the same as isolate No. 7, which was deposited in GenBank (Accession No. KF307207). A BLAST search showed 97% identity with the strain Alternaria alternata GNU-F10 (KC752593). Seven isolates were also confirmed as A. alternata by PCR identification performed by specific primers (C_for/C_rev) of A. alternata (1). Seven isolates were grown on PDA for 2 weeks and the conidia harvested. A 5-μl drop of spore suspension (1 × 105 spores/ml) was placed on each leaflet of 140 detached, surface-sterilized T. erecta leaves. Twenty leaves were inoculated with sterile distilled water as a control. The leaves were incubated in a growth chamber at 80 to 90% relative humidity, 50 to 60 klx/m2 light intensity, and a 12-h photoperiod. After 6 days, leaf spots similar to the original developed at inoculation sites for all isolates and A. alternata was consistently re-isolated. The control leaves remained symptomless. The pathogenicity test was performed three times. Leaf spot of T. erecta caused by Alternaria spp. is well known in Asian countries such as Japan (3). To our knowledge, this is the first report of A. alternata on T. erecta in the Beijing district of China. References: (1) T. Gat. Plant Dis. 96:1513, 2012. (2) E. Mirkova. J. Phytopathol. 151:323, 2003. (3) K. Tomioka. J. Gen. Plant Pathol. 66:294, 2000. (4) T. Y. Zhang. Page 284 in: Flora Fungorum Sinicorum, Volume 16: Alternaria. Science Press, Beijing, 2003.

scholarly journals First Report of Leaf Spot Disease on Cinnamomum camphora (Camphor tree) Caused by Epicoccum poaceicola in China

Plant Disease ◽  
2021 ◽  
Author(s):  
Da Li ◽  
Tianning Zhang ◽  
Qingni Song ◽  
Jun Liu ◽  
Haiyan Zhang ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Leaf Growth ◽  
Leaf Spot Disease ◽  
Molecular Characteristics ◽  
Post Inoculation ◽  
Cinnamomum Camphora ◽  
First Report ◽  
Spot Disease ◽  
Leaf Spots ◽  
Camphor Tree

As an important industrial, pharmaceutical and evergreen shade tree (Singh and Jawaid 2012), the camphor tree (Cinnamomum camphora) has been coppiced in Jiangxi Province, China. From 2017 to 2020, we noticed many camphor trees with leaf spots, with an incidence estimated at 50 to 75%, which could severely inhibit leaf growth and reduce their biomass. A dark-green circle with a watery spot appeared on the infected leaves at the initial stage, and necrosis with forming shot-spots surrounded by yellow halos occurred (Figure 1 A). Five leaves with typical symptoms were sampled and washed with tap water for ca. 15 min. Isolation and morphological analysis were performed following the method of Bao et al. (2019). Among 61 fungal isolates, 49 showed the same culture characters. Colonies on PDA were villose and regular, the reverse was scarlet at the edge of the colony, which was ca. 8.75 cm after 7 days of inoculation (Figure 1 I). Chlamydospores were aseptate, dark brown, smooth, in chains or solitary, ellipsoidal to ovoid, 4.8–9.6 × 4.8–11.1 μm (Figure 1 J). The pycnidia were produced on PDA and varied from 47.4 to 85.8 µm (mean 60.2 µm) × 38.6 to 66.8 μm (mean 49.7 μm) (n = 17) (Figure 1 K). Conidia were hyaline, unicellular, elliptical to ovoid, 4.3-6.4 µm (mean 5.1 µm) × 2.3-3.3 µm (mean 2.8 µm) (n = 52) (Figure 1 L). Pathogenicity tests of isolate XW-9 was carried out in the field. Ten leaves were wounded with a sterilized insect needle and inoculated with mycelium plugs (7-mm diameter). Non-colonized PDA plugs served as the negative controlIn addition, conidial suspensions (105 conidia/mL) of isolate XW-9 were sprayed on surface-sterilized leaves with a further ten leaves being sprayed with sterile water as the control. Symptoms described in this study appeared in 100% of the mycelium-inoculated leaves and more than 80% of the conidium-inoculated leaves after 7 days post-inoculation (Figure 1 B-E). No symptoms were seen in the controls (Figure 1 C). Three days after inoculation, brown spots resembling those observed in the field developed on the inoculated leaves, and some lesions turned into shot holes on the infected leaves (Figure 1 G & H). However, no symptoms were observed on the controls (Figure 1 F). The fungus was re-isolated from the margins of the leaf spots and labelled P-XW-9A. The gene regions for ITS, LSU, tub2, RPB2 and ACT of isolates XW-9 and P-XW-9A were amplified and sequenced. The sequences of rDNA-ITS, LSU, tub2, RPB2 and ACT of XW-9 were GenBank MW142397, MW130844, MW165322, MW446945 and MW165324, respectively and those of P-XW-9A were GenBank MW142398, MW130845, MW165323, MW446946 and MW165325, respectively (Lumbsch, et al. 2000; Aveskamp, et al. 2009; Hou et al. 2020). Phylogenetic analysis using concatenated sequences of ITS, LSU, RPB2, and tub2 showed that isolates XW-9 and P-XW-9A formed a single clade with the reference strain of E. poaceicola CBS 987.95 (Figure 2). Thus, XW-9 was identified as E. poaceicola based on its morphological and molecular characteristics. Significantly, the recovered isolate P-XW-9A also aligned with E. poaceicola fulfilling the criteria for Koch's Postulates. E. poaceicola was only reported as a fungal pathogen of Phyllostachys viridis in China (Liu et al. 2020). To our knowledge, this is the first report of leaf spot disease on camphor trees caused by E. poaceicola in China and our findings will be useful for its management.

scholarly journals First Report of Alternaria alternata Causing Black Leaf Spot of Rubber Tree in China

Plant Disease ◽  
2015 ◽  
Vol 99 (2) ◽  
pp. 290-290 ◽  
Author(s):  
Z. Y. Cai ◽  
Y. X. Liu ◽  
G. H. Li ◽  
Y. F. Wang ◽  
M. Zhou
Keyword(s):  
Alternaria Alternata ◽  
Leaf Spot ◽  
Rubber Tree ◽  
Morphological Characteristics ◽  
Correct Identification ◽  
Post Inoculation ◽  
First Report ◽  
Leaf Spots ◽  
Plastic Bags ◽  
Black Leaf Spot

We first reported Alternaria heveae (E.G. Simmons ) to be the pathogen that caused black leaf spot of rubber tree (Hevea brasiliensis Muell. Arg) in Heikou county in July 2014 (1). Black leaf spots that resembled the symptoms caused by A. heveae were observed on the leaves of rubber trees of the whole propagule collection nursery in Jingping County (22°68′ N and 103°05′ E) of Yunnan Province. Black foliar spots (0.1 to 2 mm in diameter) surrounded by a yellow halo with lesions slightly sunken on the leaf surface were observed. To confirm whether the disease was caused by the same pathogen, 5-mm2 sections were removed from the leading edge of the lesion and were surface-sterilized in 75% ethanol, air-dried, plated on potato carrot agar (PCA), and incubated at 28°C in the dark. Colonies of the fungus on PCA had round margins and little aerial mycelia with gray-black coloration after 6 days of growth on PCA (2). Medium brown conidia were found to be in short chains of two to eight spores, ovoid, obclavate, and obpyriform, with or without a short conical or cylindrical-shaped apical beak. Conidia ranged from 22.5 to 67.5 μm long (mean 39.9 μm) × 10 to 15 μm wide (mean 12.5 μm; 100 colodia were measured), with three to six transverse septa and zero to three longitudinal or oblique septa. Morphological characteristics matched the descriptions of A. alternata [(Fries) Keissler] (4).The ITS1-5.8S-ITS2 region of one single-spore isolate, Ah02JP1, was amplified with primers ITS1 and ITS4. The PCR product was sequenced directly and deposited in GenBank (Accession No. KM111289). A BLAST search of the GenBank database revealed 100% similarity with A. alternata isolates KJ829535.1, KJ677246.1, and KF813070.1. Therefore, the pathogen was identified as A. alternata on the basis of its morphological characteristics and ITS sequence. Pathogenicity of a representative isolate, Ah02JP1 was confirmed using a field rubber tree inoculation method. Three rubber plants (the clone of rubber tree Yunyan77-4) were grown to the copper-colored leaf stage. Leaves were spray-inoculated (104 conidia per milliliter spore suspension) until drops were equally distributed using a manual pressure sprayer. Three rubber plants sprayed with sterile distilled water were used as controls. After inoculation, the plants were covered with plastic bags to maintain high relative humidity. The plastic bags were removed 2 days post-inoculation (dpi), and the plants were monitored daily for symptom development. Five days post-inoculation, spots similar to the original ones seen on the field trees developed on all inoculated leaves, while control leaves remained symptomless. A. alternata was re-isolated from spray-inoculated leaves, confirming Koch's postulates. A. alternata has been reported as the causal agent of leaf blight of rubber tree in India, which initially appeared as minute spots on leaves and enlarged with the growth of the leaves (3). However, in the present study, the symptoms (black leaf spots) remained small over time after inoculation. To our knowledge, this is the first report of A. alternata on rubber tree in China. Correct identification of pathogens is essential for disease management strategies. This report will establish a foundation for the further study of Alternaria alternata to address the disease effectively. References: (1) Z. Y. Cai et al. Plant Dis. 98:1011, 2014. (2) E. Mirkova. J. Phytopathol. 151:323, 2003. (3) C. B. Roy et al. J. Plantation Crops 34:499, 2006. (4) T. Y. Zhang. Page 32 in: Flora Fungorum Sinicorum, Vol. 16: Alternaria. Science Press, Beijing, 2003.

scholarly journals First Report of Leaf Spot Disease in Withania coagulans Caused by Alternaria alternata in India

Plant Disease ◽  
2013 ◽  
Vol 97 (3) ◽  
pp. 420-420
Author(s):  
A. Sharma ◽  
V. Singh ◽  
G. Singh ◽  
P. K. Pati
Keyword(s):  
Medicinal Plant ◽  
Alternaria Alternata ◽  
Leaf Spot ◽  
Management Program ◽  
Leaf Spot Disease ◽  
Post Inoculation ◽  
Isolation Technique ◽  
Leaf Spots ◽  
Withania Coagulans ◽  
Initial Symptoms

Withania coagulans (Paneer doddi) is a medicinal plant in the Solanaceae (1) that grows in northwestern India. An unknown disease appeared in the Amritsar district of Punjab, India on W. coagulans starting in 2009, and was noticed annually in the post-monsoon seasons through 2011. The plants were grown in a net house (74.82323 to 74.82332°E, 31.63678 to 31.63688°N, 221 m elevation), Guru Nanak Dev University, Amritsar. Symptoms first appeared as brown to black spots (2 to 10 mm in diameter) that were sometimes surrounded by a yellow halo, starting on the lower leaves and gradually spreading to the upper leaves. Spots were apparent on both the dorsal and ventral sides of the leaves. In the most severe outbreak of the disease, more than 90% of the leaf area was covered with the leaf spot symptoms. The pathogen was isolated by placing pieces of surface-sterilized leaf spots on potato dextrose agar (PDA), and the hyphae that emerged from the leaf pieces were sub-cultured to PDA. Initially, the fungal colony was white, and gradually turned olive-brown as it matured. Conidiophores were mostly simple, usually becoming geniculate by sympodial elongation. Conidiophores were mostly branched and conidia were arranged in acropetal chains of 6 to 10. Conidia were 15 to 25 μm long and 5 to 10 μm wide, with 3 to 4 transverse septa and 2 to 3 longitudinal septa, muriform, ovoid to ellipsoid, with a broadly rounded base and an apical beak. Based on these morphological characters, the pathogen was identified as Alternaria alternata (Fr.) Keissler (4). The identification of the pathogen was also confirmed by MTCC, Chandigarh, India and deposited in their culture collection with Accession No. MTCC-10939 ( http://mtcc.imtech.res.in ). During preliminary studies, the optimum temperature for its growth was 25 ± 2°C. Pathogenicity of the fungus was demonstrated on three potted W. coagulans plants after spray-inoculating leaves with a spore suspension of 3 × 105 spores per ml. A batch of three plants sprayed with sterile distilled water served as controls. Both inoculated and control plants were incubated at 100% relative humidity for 5 days and transferred to a glasshouse at 25 ± 2°C. Initial symptoms developed on a few plants at 5 to 7 days post-inoculation, and the same leaf symptoms described above from field plants became apparent on all inoculated plants by 10 to 14 days. Control plants did not develop symptoms. The pathogen was recovered from leaf spots using the isolation technique described above, and was identified as A. alternata, thus fulfilling Koch's postulates. Although the leaf spot diseases caused by A. alternata and A. dianthicola were reported on W. somnifera (2,3), to the best of our knowledge, there is no report of either pathogen infecting W. coagulans. Thus, the identification of pathogen will facilitate the disease management program and for enhancing the commercial value of this important endangered medicinal plant. References: (1) S. A. Gilani et al. Afr. J. Biotechnol. 8:2948, 2009. (2) C. K. Maiti et al. Plant Dis. 91:467, 2007. (3) P. K. Pati et al. Indian J Microbiol. 48:432, 2008. (4) E. G. Simmons. Alternaria: An identification manual. American Phytopathological Society, St. Paul, MN, 2007.

scholarly journals Molecular Phylogenetic Diversity and Biological Characterization of Diaporthe Species Associated with Leaf Spots of Camellia sinensis in Taiwan

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1434
Author(s):  
Hiran A. Ariyawansa ◽  
Ichen Tsai ◽  
Jian-Yuan Wang ◽  
Patchareeya Withee ◽  
Medsaii Tanjira ◽  
...  
Keyword(s):  
Camellia Sinensis ◽  
Leaf Spot ◽  
Phylogenetic Trees ◽  
Fungal Infections ◽  
Elongation Factor ◽  
Fungal Species ◽  
Tea Leaves ◽  
Phenotypic Characters ◽  
Leaf Spots ◽  
Molecular Phylogenetic

Camellia sinensis is one of the major crops grown in Taiwan and has been widely cultivated around the island. Tea leaves are prone to various fungal infections, and leaf spot is considered one of the major diseases in Taiwan tea fields. As part of a survey on fungal species causing leaf spots on tea leaves in Taiwan, 19 fungal strains morphologically similar to the genus Diaporthe were collected. ITS (internal transcribed spacer), tef1-α (translation elongation factor 1-α), tub2 (beta-tubulin), and cal (calmodulin) gene regions were used to construct phylogenetic trees and determine the evolutionary relationships among the collected strains. In total, six Diaporthe species, including one new species, Diaporthe hsinchuensis, were identified as linked with leaf spot of C. sinensis in Taiwan based on both phenotypic characters and phylogeny. These species were further characterized in terms of their pathogenicity, temperature, and pH requirements under laboratory conditions. Diaporthe tulliensis, D. passiflorae, and D. perseae were isolated from C. sinensis for the first time. Furthermore, pathogenicity tests revealed that, with wound inoculation, only D. hongkongensis was pathogenic on tea leaves. This investigation delivers the first assessment of Diaporthe taxa related to leaf spots on tea in Taiwan.

scholarly journals A New Bacterial Disease on Bluberry (Vaccinium Corymbosum) Caused by Pseudomonas Spp.

2013 ◽  
Vol 53 (1) ◽  
pp. 32-36 ◽  
Author(s):  
Monika Kałużna ◽  
Joanna Puławska ◽  
Beata Meszka
Keyword(s):  
Hypersensitivity Reaction ◽  
Pseudomonas Syringae ◽  
Vaccinium Corymbosum ◽  
Leaf Spot Disease ◽  
Bacterial Disease ◽  
Pseudomonas Spp ◽  
Leaf Spots ◽  
Pectolytic Activity ◽  
Young Leaves ◽  
First Time

Abstract In 2011, leaf spot disease was observed on the blueberry (Vaccinium corymbosum) cv. Nelson growing on a commercial field located in Central Poland. The disease symptoms could be seen as russet brown, irregular spots. The diameter of the spots was 0.3-0.5 cm, and the spots often coalesced. From these leaf spots, a fluorescent bacterium was repeatedly isolated in almost pure culture. Polymerase chain reaction (PCR) using primers Ps-for and Ps-rev, specific for Pseudomonas spp. confirmed that they belong to this genus. Based on LOPAT tests [levan production from sucrose (L), presence of oxidase (O), pectolytic activity on potato (P), the presence of arginine dihydrolase (A), hypersensitivity reaction on tobacco (T)], 6 isolates were classified to the LOPAT group Ib - group of Pseudomonas syringae subsp. savastanoi and Pseudomonas delphini, and one isolate to group Ia - P. syringae. All isolates caused a hypersensitivity reaction on tobacco plants, and symptoms similar to those under natural conditions, when young leaves of blueberry cv. Nelson were inoculated. Sequence analysis of 16S rRNA and rpoB genes showed the highest similarity of 6 studied strains to the species P. avellanae. Further taxonomic study is necessary to enable definitive classification of these isolates. It is the first time that a bacterial disease caused by the Pseudomonas spp. was observed in Poland.

scholarly journals First Report of Alternaria Leaf Spot of Banana Caused by Alternaria alternata in the United States

Plant Disease ◽  
2013 ◽  
Vol 97 (8) ◽  
pp. 1116-1116 ◽  
Author(s):  
V. Parkunan ◽  
S. Li ◽  
E. G. Fonsah ◽  
P. Ji
Keyword(s):  
United States ◽  
Alternaria Alternata ◽  
Leaf Spot ◽  
Morphological Characteristics ◽  
The United States ◽  
Its Sequencing ◽  
Single Spore ◽  
First Report ◽  
Alternaria Leaf Spot ◽  
Leaf Spots

Research efforts were initiated in 2003 to identify and introduce banana (Musa spp.) cultivars suitable for production in Georgia (1). Selected cultivars have been evaluated since 2009 in Tifton Banana Garden, Tifton, GA, comprising of cold hardy, short cycle, and ornamental types. In spring and summer of 2012, 7 out of 13 cultivars (African Red, Blue Torres Island, Cacambou, Chinese Cavendish, Novaria, Raja Puri, and Veinte Cohol) showed tiny, oval (0.5 to 1.0 mm long and 0.3 to 0.9 mm wide), light to dark brown spots on the adaxial surface of the leaves. Spots were more concentrated along the midrib than the rest of the leaf and occurred on all except the newly emerged leaves. Leaf spots did not expand much in size, but the numbers approximately doubled during the season. Disease incidences on the seven cultivars ranged from 10 to 63% (10% on Blue Torres Island and 63% on Novaria), with an average of 35% when a total of 52 plants were evaluated. Six cultivars including Belle, Ice Cream, Dwarf Namwah, Kandarian, Praying Hands, and Saba did not show any spots. Tissue from infected leaves of the seven cultivars were surface sterilized with 0.5% NaOCl, plated onto potato dextrose agar (PDA) media and incubated at 25°C in the dark for 5 days. The plates were then incubated at room temperature (23 ± 2°C) under a 12-hour photoperiod for 3 days. Grayish black colonies developed from all the samples, which were further identified as Alternaria spp. based on the dark, brown, obclavate to obpyriform catenulate conidia with longitudinal and transverse septa tapering to a prominent beak attached in chains on a simple and short conidiophore (2). Conidia were 23 to 73 μm long and 15 to 35 μm wide, with a beak length of 5 to 10 μm, and had 3 to 6 transverse and 0 to 5 longitudinal septa. Single spore cultures of four isolates from four different cultivars were obtained and genomic DNA was extracted and the internal transcribed spacer (ITS1-5.8S-ITS2) regions of rDNA (562 bp) were amplified and sequenced with primers ITS1 and ITS4. MegaBLAST analysis of the four sequences showed that they were 100% identical to two Alternaria alternata isolates (GQ916545 and GQ169766). ITS sequence of a representative isolate VCT1FT1 from cv. Veinte Cohol was submitted to GenBank (JX985742). Pathogenicity assay was conducted using 1-month-old banana plants (cv. Veinte Cohol) grown in pots under greenhouse conditions (25 to 27°C). Three plants were spray inoculated with the isolate VCT1FT1 (100 ml suspension per plant containing 105 spores per ml) and incubated under 100% humidity for 2 days and then kept in the greenhouse. Three plants sprayed with water were used as a control. Leaf spots identical to those observed in the field were developed in a week on the inoculated plants but not on the non-inoculated control. The fungus was reisolated from the inoculated plants and the identity was confirmed by morphological characteristics and ITS sequencing. To our knowledge, this is the first report of Alternaria leaf spot caused by A. alternata on banana in the United States. Occurrence of the disease on some banana cultivars in Georgia provides useful information to potential producers, and the cultivars that were observed to be resistant to the disease may be more suitable for production. References: (1) E. G. Fonsah et al. J. Food Distrib. Res. 37:2, 2006. (2) E. G. Simmons. Alternaria: An identification manual. CBS Fungal Biodiversity Center, Utrecht, Netherlands, 2007.

scholarly journals First Report of a Leaf Spot Disease of Bells-of-Ireland (Moluccella laevis) Caused by Cercospora apii in California

Plant Disease ◽  
2003 ◽  
Vol 87 (2) ◽  
pp. 203-203
Author(s):  
S. T. Koike ◽  
S. A. Tjosvold ◽  
J. Z. Groenewald ◽  
P. W. Crous
Keyword(s):  
Leaf Spot ◽  
Sequence Data ◽  
Disease Incidence ◽  
Leaf Spot Disease ◽  
Conidial Suspension ◽  
Internal Transcribed Spacer Region ◽  
First Report ◽  
Spot Disease ◽  
Leaf Spots ◽  
Initial Symptoms

Bells-of-Ireland (Moluccella laevis) (Lamiaceae) is an annual plant that is field planted in coastal California (Santa Cruz County) for commercial cutflower production. In 2001, a new leaf spot disease was found in these commercially grown cutflowers. The disease was most serious in the winter-grown crops in 2001 and 2002, with a few plantings having as much as 100% disease incidence. All other plantings that were surveyed during this time had at least 50% disease. Initial symptoms consisted of gray-green leaf spots. Spots were generally oval in shape, often delimited by the major leaf veins, and later turned tan. Lesions were apparent on both adaxial and abaxial sides of the leaves. A cercosporoid fungus having fasciculate conidiophores, which formed primarily on the abaxial leaf surface, was consistently associated with the spots. Based on morphology and its host, this fungus was initially considered to be Cercospora molucellae Bremer & Petr., which was previously reported on leaves of M. laevis in Turkey (1). However, sequence data obtained from the internal transcribed spacer region (ITS1, ITS2) and the 5.8S gene (STE-U 5110, 5111; GenBank Accession Nos. AY156918 and AY156919) indicated there were no base pair differences between the bells-of-Ireland isolates from California, our own reference isolates of C. apii, as well as GenBank sequences deposited as C. apii. Based on these data, the fungus was subsequently identified as C. apii sensu lato. Pathogenicity was confirmed by spraying a conidial suspension (1.0 × 105 conidia/ml) on leaves of potted bells-of-Ireland plants, incubating the plants in a dew chamber for 24 h, and maintaining them in a greenhouse (23 to 25°C). After 2 weeks, all inoculated plants developed leaf spots that were identical to those observed in the field. C. apii was again associated with all leaf spots. Control plants, which were treated with water, did not develop any symptoms. The test was repeated and the results were similar. To our knowledge this is the first report of C. apii as a pathogen of bells-of-Ireland in California. Reference: (1) C. Chupp. A Monograph of the Fungus Genus Cercospora. Cornell University Press, Ithaca, New York, 1954.

scholarly journals Metabolism of Gallic Acid and Its Distributions in Tea (Camellia sinensis) Plants at the Tissue and Subcellular Levels

2020 ◽  
Vol 21 (16) ◽  
pp. 5684 ◽  
Author(s):  
Xiaochen Zhou ◽  
Lanting Zeng ◽  
Yingjuan Chen ◽  
Xuewen Wang ◽  
Yinyin Liao ◽  
...  
Keyword(s):  
Gallic Acid ◽  
Camellia Sinensis ◽  
Tea Plant ◽  
Plant Diseases ◽  
Tea Leaves ◽  
Specialized Metabolites ◽  
Tea Plants ◽  
Mg Content ◽  
Ga Content

In tea (Camellia sinensis) plants, polyphenols are the representative metabolites and play important roles during their growth. Among tea polyphenols, catechins are extensively studied, while very little attention has been paid to other polyphenols such as gallic acid (GA) that occur in tea leaves with relatively high content. In this study, GA was able to be transformed into methyl gallate (MG), suggesting that GA is not only a precursor of catechins, but also can be transformed into other metabolites in tea plants. GA content in tea leaves was higher than MG content—regardless of the cultivar, plucking month or leaf position. These two metabolites occurred with higher amounts in tender leaves. Using nonaqueous fractionation techniques, it was found that GA and MG were abundantly accumulated in peroxisome. In addition, GA and MG were found to have strong antifungal activity against two main tea plant diseases, Colletotrichum camelliae and Pseudopestalotiopsis camelliae-sinensis. The information will advance our understanding on formation and biologic functions of polyphenols in tea plants and also provide a good reference for studying in vivo occurrence of specialized metabolites in economic plants.

scholarly journals First Report of Leaf Spot Disease Caused by Epicoccum nigrum on Lablab purpureus in India

Plant Disease ◽  
2014 ◽  
Vol 98 (2) ◽  
pp. 284-284 ◽  
Author(s):  
S. Mahadevakumar ◽  
K. M. Jayaramaiah ◽  
G. R. Janardhana
Keyword(s):  
Leaf Spot ◽  
Leaf Surface ◽  
Disease Incidence ◽  
Leaf Spot Disease ◽  
Post Inoculation ◽  
Conidial Suspension ◽  
Lablab Purpureus ◽  
First Report ◽  
Spot Disease ◽  
Epicoccum Nigrum

Lablab purpureus (L.) Sweet (Indian bean) is an important pulse crop grown in arid and semi-arid regions of India. It is one of the most widely cultivated legume species and has multiple uses. During a September 2010 survey, we recorded a new leaf spot disease on L. purpureus in and around Mysore district (Karnataka state) with 40 to 80% disease incidence in 130 ha of field crop studied, which accounted for 20 to 35% estimated yield loss. The symptoms appeared as small necrotic spots on the upper leaf surface. The leaf spots were persistent under mild infection throughout the season with production of conidia in clusters on abaxial leaf surface. A Dueteromyceteous fungus was isolated from affected leaf tissues that were surface sterilized with 2% NaOCl2 solution then washed thrice, dried, inoculated on potato dextrose agar (PDA) medium, and incubated at 28 ± 2°C at 12 h alternate light and dark period for 7 days. The fungal colony with aerial mycelia interspersed with dark cushion-shaped sporodochia consists of short, compact conidiophores bearing large isodiametric, solitary, muricate, brown, globular to pear shaped conidia (29.43 to 23.92 μm). Fungal isolate was identified as Epicoccum sp. based on micro-morphological and cultural features (1). Further authenticity of the fungus was confirmed by PCR amplification of the internal transcribed spacer (ITS) region using ITS1/ITS4 universal primer. The amplified PCR product was purified, sequenced directly, and BLASTn search revealed 100% homology to Epicoccum nigrum Link. (DQ093668.1 and JX914480.1). A representative sequence of E. nigrum was deposited in GenBank (Accession No. KC568289.1). The isolated fungus was further tested for its pathogenicity on 30-day-old healthy L. purpureus plants under greenhouse conditions. A conidial suspension (106 conidia/ml) was applied as foliar spray (three replicates of 15 plants each) along with suitable controls. The plants were kept under high humidity (80%) for 5 days and at ambient temperature (28 ± 2°C). The appearance of leaf spot symptoms were observed after 25 days post inoculation. Further, the pathogen was re-isolated and confirmed by micro-morphological characteristics. E. nigrum has been reported to cause post-harvest decay of cantaloupe in Oklahoma (2). It has also been reported as an endophyte (3). Occurrence as a pathogen on lablab bean has not been previously reported. To our knowledge, this is the first report of the occurrence of E. nigrum on L. purpureus in India causing leaf spot disease. References: (1) H. L. Barnet and B. B. Hunter. Page 150 in: Illustrated Genera of Imperfect Fungi, 1972. (2) B. D. Bruten et al. Plant Dis. 77:1060, 1993. (3) L. C. Fávaro et al. PLoS One 7(6):e36826, 2012.

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