scholarly journals First Report of Alternaria alternata Causing Leaf Spot on Kidney Bean in China

Plant Disease ◽  
2021 ◽  
Author(s):  
Yazhong Jin ◽  
YaNan Xiong ◽  
Yuhu Zuo ◽  
YouLi Zhang ◽  
Xueqing Geng ◽  
...  
Keyword(s):  
Phaseolus Vulgaris ◽  
Leaf Spot ◽  
Leaf Tissue ◽  
Its Region ◽  
French Bean ◽  
Kidney Bean ◽  
Distilled Water ◽  
Heilongjiang Province ◽  
Vegetable Crops ◽  
Bean Plants

Kidney bean (Phaseolus vulgaris), also being known as common bean, dry bean or french bean, is one of the most precious and highly nutritious legume crop cultivated and consumed worldwide(Blair et al.,2012; Choudhary et al.,2018) , which is an important edible foods or one of the most economically important vegetable crops in China. It is widely grown in the Heilongjiang Province in China. In July of 2020, leaf spot symptoms were found on the old or new leaves of Kidney bean plants (Phaseolus vulgaris L.) in our experimental fields located in Zhaozhou County(N45°42 '20.16 ", E125°15' 58.63" ), Daqing City, Heilongjiang Province, China. This field had disease incidences of approximately 20%. The leaf spot is conducive to the onset at high temperature and humidity environment, and this disease spreads very quickly after rainy days, therefore it is potentially a large risk for the development of Kidney bean industry. In its early occurrence phase, the infected leaves showed yellowish halo on the leaves, in which the middle mesophyll lost green. Thereafter, the yellow halo turned brown, and the middle leaf tissue of the halo appeared brown, ultimately the whole leaves had many brown spots (Supplementary Figure S1). To isolate the pathogen, diseased tissue (5×5 mm) was excised from the margins of individual lesions from the leaves of diseased plants with typical symptoms, and was disinfected with 75% ethanol for 10s followed by 2% NaClO for 3 min and then washed five to eight times with sterile water. Afterwards, the samples were transferred to potato dextrose agar (PDA) plates and incubated. After 5 to 7 days of incubation at 25°C (Wei et al.,2018), the mycelia were dark green with white margins in obverse and dark in reverse. Conidiophores were light brown with 2 to 4 septa and obclavate, 17.5to 44.0 × 6.5 to 14.5μm, with a short beak, and with 1 to 5 transverse septa and 0 to 2 longitudinal septa, light brown to olive-brown (Supplementary Figure S2). Based on morphological features and sporulation pattern, the pathogen was similar to characteristics described Alternaria alternate (Zhou et al,2014), being identified as A. alternata. To confirm pathogenicity, the isolates were cultured on PCA for 7days to prepare conidial suspensions, then being produced a final concentration of 1×108 spores/ml. Five potted Kidney bean plants were sprayed with conidial suspensions, and five control potted plants were sprayed with sterile distilled water, in which these potted Kidney bean plants were treated after wiping each leaf surface with 75% ethanol and washing each leaf with sterilized distilled water five times. These plants were incubated in an artificial growth chamber at 26 to 28°C with a 12 h light/dark photoperiod, with 85% relative humidity. After 3 days, yellowish halo lesions appeared on the inoculated plants, and pale lesions with distinct dark brownish red borders on Kidney bean leaves were observed after eight days, but no lesions were observed on the control leaves. Pathogenicity tests were repeated three times. The internal transcribed spacer (ITS) region of rDNA was amplified and sequenced with primers ITS1/ITS4. BLAST analysis of the sequences showed 100% sequence identity with a pathogenic A. alternata (Fr.) Keissl (Supplementary Figure S3), and the nucleotide sequence of the ITS region was submitted to GenBank under accession MZ951052. In China, there are no detailed records about the causal agent of this disease on Kidney bean in a paper in Chinese. To our knowledge, this is the first confirmed report of leaf spot causing by A. alternata on Kidney bean in China.

scholarly journals First Report of Leaf Spot of Sweet Basil Caused by Cercospora guatemalensis in Korea

Plant Disease ◽  
2012 ◽  
Vol 96 (10) ◽  
pp. 1580-1580
Author(s):  
J. H. Park ◽  
K. S. Han ◽  
J. Y. Kim ◽  
H. D. Shin
Keyword(s):  
Leaf Spot ◽  
Morphological Characteristics ◽  
Its Region ◽  
Culture Collection ◽  
Distilled Water ◽  
First Report ◽  
Sweet Basil ◽  
Organic Farm ◽  
Leaf Spots ◽  
Close Phylogenetic Relationship

Sweet basil, Ocimum basilicum L., is a fragrant herb belonging to the family Lamiaceae. Originated in India 5,000 years ago, sweet basil plays a significant role in diverse cuisines across the world, especially in Asian and Italian cooking. In October 2008, hundreds of plants showing symptoms of leaf spot with nearly 100% incidence were found in polyethylene tunnels at an organic farm in Icheon, Korea. Leaf spots were circular to subcircular, water-soaked, dark brown with grayish center, and reached 10 mm or more in diameter. Diseased leaves defoliated prematurely. The damage purportedly due to this disease has reappeared every year with confirmation of the causal agent made again in 2011. A cercosporoid fungus was consistently associated with disease symptoms. Stromata were brown, consisting of brown cells, and 10 to 40 μm in width. Conidiophores were fasciculate (n = 2 to 10), olivaceous brown, paler upwards, straight to mildly curved, not geniculate in shorter ones or one to two times geniculate in longer ones, 40 to 200 μm long, occasionally reaching up to 350 μm long, 3.5 to 6 μm wide, and two- to six-septate. Conidia were hyaline, acicular to cylindric, straight in shorter ones, flexuous to curved in longer ones, truncate to obconically truncate at the base, three- to 16-septate, and 50 to 300 × 3.5 to 4.5 μm. Morphological characteristics of the fungus were consistent with the previous reports of Cercospora guatemalensis A.S. Mull. & Chupp (1,3). Voucher specimens were housed at Korea University herbarium (KUS). An isolate from KUS-F23757 was deposited in the Korean Agricultural Culture Collection (Accession No. KACC43980). Fungal DNA was extracted with DNeasy Plant Mini DNA Extraction Kits (Qiagen Inc., Valencia, CA). The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced. The resulting sequence of 548 bp was deposited in GenBank (Accession No. JQ995781). This showed >99% similarity with sequences of many Cercospora species, indicating their close phylogenetic relationship. Isolate of KACC43980 was used in the pathogenicity tests. Hyphal suspensions were prepared by grinding 3-week-old colonies grown on PDA with distilled water using a mortar and pestle. Five plants were inoculated with hyphal suspensions and five plants were sprayed with sterile distilled water. The plants were covered with plastic bags to maintain a relative humidity of 100% for 24 h and then transferred to a 25 ± 2°C greenhouse with a 12-h photoperiod. Typical symptoms of necrotic spots appeared on the inoculated leaves 6 days after inoculation, and were identical to the ones observed in the field. C. guatemalensis was reisolated from symptomatic leaf tissues, confirming Koch's postulates. No symptoms were observed on control plants. Previously, the disease was reported in Malawi, India, China, and Japan (2,3), but not in Korea. To our knowledge, this is the first report of C. guatemalensis on sweet basil in Korea. Since farming of sweet basil has recently started on a commercial scale in Korea, the disease poses a serious threat to safe production of this herb, especially in organic farming. References: (1) C. Chupp. A Monograph of the Fungus Genus Cercospora. Ithaca, NY, 1953. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology & Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , May 5, 2012. (3) J. Nishikawa et al. J. Gen. Plant Pathol. 68:46, 2002.

scholarly journals Allelopathic Interactions of Parthenium hysterophorous with Kidney Bean, Phaseolus vulgaris

2020 ◽  
pp. 25-33
Author(s):  
H. M. Tsingalia ◽  
J. M. Auma
Keyword(s):  
Phaseolus Vulgaris ◽  
Seed Germination ◽  
Leaf Extract ◽  
Shoot Growth ◽  
Combined Treatment ◽  
Kidney Bean ◽  
Root Extract ◽  
Indigenous Species ◽  
Distilled Water ◽  
Leaf Extracts

Allelopathy, an important mechanism in invasive species stems from the lack of coevolved tolerance of indigenous species to novel chemicals released by the invader species. These chemicals are key to successful invasive of species of natural plant communities and ecosystems. This study analyzed the allelopathic effects of the invasive plant, Parthenium hysterophorous on the growth of kidney beans (Phaseolus vulgaris). One hundred and fifty viable kidney bean seeds were washed in distilled water, and transferred in triplicates to pots with wet sterile sand. Ten grams of freshly collected Parthenium leaves and roots were weighed, grounded separately using a mortar and a pestle, mixed with 100 ml of distilled water in a beaker and left for 24 hours in a dark at a room temperature (250C). The aqueous extract filtrates were used in experimental treatments. While untreated (control) seeds germinated on day 4 seeds treated with leaf extract germinated on day 14 and day 9 for the root extract. Leaf extract inhibited germination and sprouting of new leaves more effectively than root extract. Leaves in control seeds appeared on day 1 after germination. In treated seeds, leaves appeared on the 4th day then stagnated until day 15 when more leaves sprouted. Root extract significantly depressed seed germination. The number of new leaves increased significantly in control seedlings compared to the treated ones. Combined root and leaf extracts highly significantly inhibited of seed germination and the number of new leaves. Additionally, combined treatment with root and leaf extracts significantly inhibited shoot growth, and the increase in leaf length and width. A comparison of the effectiveness of the root and leaf extracts showed that leaf extract was more effective in inhibiting shoot growth and leaf width than the root extract.

Localization of Atrazine in Corn (Zea mays), Oat (Avena sativa), and Kidney Bean (Phaseolus vulgaris) Leaf Cells

Weed Science ◽  
1983 ◽  
Vol 31 (5) ◽  
pp. 664-671 ◽  
Author(s):  
Robert F. Norris ◽  
Ivy E. Fong
Keyword(s):  
Zea Mays ◽  
Phaseolus Vulgaris ◽  
Avena Sativa ◽  
Gradient Centrifugation ◽  
Leaf Tissue ◽  
Kidney Bean ◽  
Vascular Bundles ◽  
Sucrose Density Gradient Centrifugation ◽  
Test Species ◽  
Subcellular Organelles

Corn (Zea maysL. ‘DeKalb 640′), kidney beans (Phaseolus vulgarisL. ‘Light red’) and oats (Avena sativaL. ‘Kanota’) were grown in solution culture and the roots exposed to radioactively labeled atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine]. The radioactivity from3H-atrazine, or its metabolites, was located in microautoradiographs of corn leaf sections, almost exclusively at the perimeter of the vascular bundles, and was primarily confined to the cell walls and intercellular spaces, with no activity associated with subcellular organelles. Radioactivity from3H-atrazine in oat leaf section microautoradiographs was primarily associated with the chloroplasts, with no evidence of radioactivity specifically associated with other subcellular organelles. Sucrose density gradient centrifugation of homogenized leaf tissue following exposure of the plants to14C-atrazine showed that most of the radioactivity was associated with the light cell fragments and cytoplasm for the test species. There was no accumulation of14C-activity in any of the heavier subcellular organelles from corn leaf cells. A peak of radioactivity was associated with the chloroplast fraction from oat and kidney bean leaves.

Phenolic and Oxidative Metabolism as Bioindicators of Nitrogen Deficiency in French Bean Plants (Phaseolus vulgaris L. cv. Strike)

Plant Biology ◽  
2000 ◽  
Vol 2 (3) ◽  
pp. 272-277 ◽  
Author(s):  
E. Sánchez ◽  
J. M. Soto ◽  
P. C. García ◽  
L. R. López-Lefebre ◽  
R. M. Rivero ◽  
...  
Keyword(s):  
Phaseolus Vulgaris ◽  
Oxidative Metabolism ◽  
Nitrogen Deficiency ◽  
French Bean ◽  
Phaseolus Vulgaris L ◽  
Bean Plants

scholarly journals First Report of a Chaetomella sp. Causing a Leaf Spot on Sansevieria trifasciata in China

Plant Disease ◽  
2013 ◽  
Vol 97 (7) ◽  
pp. 992-992 ◽  
Author(s):  
Y. L. Li ◽  
Z. Zhou ◽  
W. Lu ◽  
J. R. Ye
Keyword(s):  
Leaf Spot ◽  
Disease Incidence ◽  
Morphological Characteristics ◽  
Leaf Tissue ◽  
Aerial Mycelium ◽  
Control Treatment ◽  
Distilled Water ◽  
First Report ◽  
Potted Plants ◽  
Fungal Isolates

Sansevieria trifasciata originates from tropical West Africa. It is widely planted as a potted ornamental in China for improving indoor air quality (1). In February 2011, leaves of S. trifasciata plants in an ornamental market of Anle, Luoyang City, China, were observed with sunken brown lesions up to 20 mm in diameter, and with black pycnidia present in the lesions. One hundred potted plants were examined, with disease incidence at 20%. The symptomatic leaves affected the ornamental value of the plants. A section of leaf tissue from the periphery of two lesions from a plant was cut into 1 cm2 pieces, soaked in 70% ethanol for 30 s, sterilized with 0.1% HgCl2 for 2 min, then washed five times in sterilized distilled water. The pieces were incubated at 28°C on potato dextrose agar (PDA). Colonies of two isolates were brown with submerged hyphae, and aerial mycelium was rare. Abundant and scattered pycnidia were reniform, dark brown, and 200 to 350 × 100 to 250 μm. There were two types of setae on the pycnidia: 1) dark brown setae with inward curved tops, and 2) straight, brown setae. Conidia were hyaline, unicellular, cylindrical, and 3.75 to 6.25 × 1.25 to 2.50 μm. Morphological characteristics suggested the two fungal isolates were a Chaetomella sp. To confirm pathogenicity, six mature leaves of a potted S. trifasciata plant were wounded with a sterile pin after wiping each leaf surface with 70% ethanol and washing each leaf with sterilized distilled water three times. A 0.5 cm mycelial disk cut from the margin of a 5-day-old colony on a PDA plate was placed on each pin-wounded leaf, ensuring that the mycelium was in contact with the wound. Non-colonized PDA discs were placed on pin-wounded leaves as the control treatment. Each of two fungal isolates was inoculated on two leaves, and the control treatment was done similarly on two leaves. The inoculated plant was placed in a growth chamber at 28°C with 80% relative humidity. After 7 days, inoculated leaves produced brown lesions with black pycnidia, but no symptoms developed on the control leaves. A Chaetomella sp. was reisolated from the lesions of inoculated leaves, but not from the control leaves. An additional two potted plants were inoculated using the same methods as replications of the experiment, with identical results. To confirm the fungal identification, the internal transcribed spacer (ITS) region of rDNA of the two isolates was amplified using primers ITS1 and ITS4 (2) and sequenced. The sequences were identical (GenBank Accession No. KC515097) and exhibited 99% nucleotide identity to the ITS sequence of an isolate of Chaetomella sp. in GenBank (AJ301961). To our knowledge, this is the first report of a leaf spot of S. trifasciata caused by Chaetomella sp. in China as well as anywhere in the world. References: (1) X. Z. Guo et al. Subtropical Crops Commun. Zhejiang 27:9, 2005. (2) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, CA, 1990.

scholarly journals Occurrence and Host Range of Ascochyta Phaseolorum in Queensland

1968 ◽  
Vol 21 (6) ◽  
pp. 1143 ◽  
Author(s):  
JLA lcorn
Keyword(s):  
Phaseolus Vulgaris ◽  
Host Range ◽  
French Bean ◽  
Indigenous Species ◽  
Vegetable Crops ◽  
Wide Host Range ◽  
Natural Hosts

The presence of Ascochyta phaseolorum as a pathogen of Phaseolus vulgaris in Queensland is reported. The fungus has been found to have a wide host range including vegetable crops, pastures, weeds, and indigenous species. Natural infections were found in 48 hosts in 14 families, and an additional 12 species proved susceptible when inoculated experimentally. Pathogenicity of isolates from French bean towards many of the natural hosts has been demonstrated, and in reciprocal inoculations cultures from field�infected hosts produced symptoms on bean typical of those produced by bean isolates. The fungus is shown to be a weak parasite, requiring some form of wounding to initiate infection under Queensland conditions.

scholarly journals An Outbreak of Leaf Spot Caused by Stemphylium solani on Eggplant in Malaysia

Plant Disease ◽  
2013 ◽  
Vol 97 (5) ◽  
pp. 689-689
Author(s):  
A. Nasehi ◽  
J. B. Kadir ◽  
M. Nasr Esfahani ◽  
F. Mahmodi ◽  
H. Ghadirian ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Direct Sequencing ◽  
Disease Incidence ◽  
Solanum Melongena ◽  
Its Region ◽  
Gray Leaf Spot ◽  
Distilled Water ◽  
Conidial Suspension ◽  
Morphological Criteria ◽  
Pathogenicity Testing

In 2011, a severe gray leaf spot was observed on eggplant (Solanum melongena) in major eggplant growing areas in Malaysia, including the Pahang, Johor, and Selangor states. Disease incidence was >70% in severely infected areas of about 150 ha of eggplant greenhouses and fields examined. Symptoms initially appeared as small (1 to 5 mm diameter), brownish-black specks with concentric circles on the lower leaves. The specks then coalesced and developed into greyish-brown, necrotic lesions, which also appeared on the upper leaves. Eventually, the leaves senesced and were shed. Tissue cut from the edges of leaf spots were surface-sterilized in 1% NaOCl for 2 min, rinsed in sterilized water, dried, and incubated on potato dextrose agar (PDA). Fungal colonies were greyish green to light brown, and produced a yellow pigment. Single, muriform, brown, oblong conidia formed at the terminal end of each conidiophore, were each 21.6 to 45.6 μm long and 11.5 to 21.6 μm wide, and contained 2 to 7 transverse and 1 to 4 longitudinal septa. The conidiophores were tan to light brown and ≤220 μm long. Based on these morphological criteria, 25 isolates of the fungus were identified as Stemphylium solani (1). To produce conidia in culture, 7-day-old single-conidial cultures were established on potato carrot agar (PCA) and V8 juice agar media under an 8-h/16-h light/dark photoperiod at 25°C (4). Further confirmation of the identification was obtained by molecular characterization in which fungal DNA was extracted and the internal transcribed spacer (ITS) region of ribosomal DNA amplified using primers ITS5 and ITS4 (2), followed by direct sequencing. A BLAST search in the NCBI database revealed that the sequence was 99% identical with published ITS sequences for two isolates of S. solani (Accession Nos. AF203451 and HQ840713). The amplified ITS region was deposited in GenBank (JQ736023). Pathogenicity testing of a representative isolate was performed on detached, 45-day-old eggplant leaves of the cv. 125066-X under laboratory conditions. Four fully expanded leaves (one wounded and two non-wounded leaflets/leaf) were placed on moist filter paper in petri dishes, and each leaflet inoculated with a 20-μl drop of a conidial suspension containing 1 × 105 conidia/ml in sterilized, distilled water (3). The leaves were wounded by applying pressure to leaf blades with the serrated edge of forceps. Four control leaves were inoculated similarly with sterilized, distilled water. Inoculated leaves were incubated in humid chambers at 25°C with 95% RH and a 12-h photoperiod. After 7 days, symptoms similar to those observed in the original fields developed on both wounded and non-wounded inoculated leaves, but not on control leaves, and S. solani was reisolated consistently from the symptoms using the same method as the original isolations. Control leaves remained asymptomatic and the fungus was not isolated from these leaves. The pathogenicity testing was repeated with similar results. To our knowledge, this is the first report of S. solani on eggplant in Malaysia. References: (1) B. S. Kim et al. Plant Pathol. J. 20:85, 2004. (2) Y. R. Mehta et al. Curr. Microbiol. 44:323, 2002. (3) B. M. Pryor and T. J. Michailides. Phytopathology 92:406, 2002. (4) E. G. Simmons. CBS Biodiv. Series 6:775, 2007.

scholarly journals First Report of a Leaf Spot on Hazel Leaves Caused by Phyllosticta coryli in Liaoning Province of China

Plant Disease ◽  
2013 ◽  
Vol 97 (9) ◽  
pp. 1254-1254 ◽  
Author(s):  
J. Sun ◽  
D.-M. Wang ◽  
X.-Y. Huang ◽  
Z.-H. Liu
Keyword(s):  
Leaf Spot ◽  
Control Strategies ◽  
Morphological Characteristics ◽  
Leaf Tissue ◽  
Its Region ◽  
Liaoning Province ◽  
Single Spore ◽  
First Report ◽  
Leaf Spots ◽  
Microscopic Morphology

Hazel (Corylus heterophylla Fischl) is an important nut tree grown in China, especially in Liaoning Province, and is rich in nutritional and medicinal values. In August 2011, leaf spotting was observed on hybrid hazel (Dawei) leaves in Paotai Town, Wafangdian County of Liaoning Province. By August 2012, the disease had spread to Zhangdang Town, Fushun County. Symptoms initially appeared on both sides of leaves as pinpoint brown spots, which enlarged and developed into regular, dark brown lesions, 3 to 9 mm in diameter. The lesions were lighter in color in the center compared to the margin. To identify the pathogen, leaf pieces (3 to 5 mm) taken from the margins, including both symptomatic and healthy portions of leaf tissue, were surface-disinfected first in 75% ethanol for 5 s, next in 0.1% aqueous mercuric chloride for 50 s, and then rinsed with sterilized water three times. Leaf pieces were incubated on potato dextrose agar (PDA) at 25°C for 14 days in darkness. Single spore isolates were obtained from individual conidia. For studies of microscopic morphology, isolates were grown on synthetic nutrient agar (SNA) in slide cultures. Colonies grew up to 45 to 48 mm in diameter on PDA after 14 days. Pycnidia appeared on the colonies after 12 days. Conidiophores were short. Pycnidia were dark brown, subglobose, and 150 to 205 μm in diameter. Conidia were unicellular, colorless, ovoid to oval, and from 2.4 to 4.5 × 1.6 to 2.4 μm. On the basis of these morphological characteristics, the isolates were tentatively identified as Phyllosticta coryli Westend (2). The rDNA internal transcribed spacer (ITS) region was amplified using primers ITS1 and ITS4 and sequenced (GenBank Accession No. KC196068). The 490-bp amplicons had 100% identity to an undescribed Phyllosticta species isolated from Cornus macrophylla in Gansu, Tianshui, China (AB470897). On the basis of morphological characteristics and nucleotide homology, the isolate was tentatively identified as P. coryli. Koch's postulates were fulfilled in the growth chamber on hazelnut leaves inoculated with P. coryli conidial suspensions (107 conidia ml–1). Eight inoculated 1-year-old seedlings (Dawei) were incubated under moist conditions for 8 to 10 days at 25°C. All leaf spots that developed on inoculated leaves were similar in appearance to those observed on diseased hazel leaves in the field. P. coryli was recovered from lesions and its identity was confirmed by morphological characteristics. P. coryli was first reported as a pathogen of hazel leaves in Bull of Belgium (2). In China, P. coryli was first reported on Corylus heterophylla Fisch. in Jilin Province (1). To our knowledge, this is the first report of P. coryli causing leaf spot on hybrid hazel in Liaoning Province of China. The outbreak and spread of this disease may decrease the yield of hazelnut in northern regions of China. More studies are needed on control strategies, including the possible resistance of hazel cultivars to P. coryli. References: (1) Y. Li et al. J. Shenyang Agric. Univ. 25:153, 1994. (2) P. A. Saccardo. Sylloge Fungorum Vol. III, page 31, 1884.

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