scholarly journals Association Analysis and Identification of SNP Markers for Stemphylium Leaf Spot (<i>Stemphylium botryosum</i> f. sp. <i>spinacia</i>) Resistance in Spinach (<i>Spinacia oleracea</i>)

2016 ◽  
Vol 07 (12) ◽  
pp. 1600-1611 ◽  
Author(s):  
Ainong Shi ◽  
Beiquan Mou ◽  
Jim Correll ◽  
Steven T. Koike ◽  
Dennis Motes ◽  
...  
Keyword(s):  
Association Analysis ◽  
Leaf Spot ◽  
Spinacia Oleracea ◽  
Snp Markers ◽  
Stemphylium Botryosum

scholarly journals High resolution mapping and candidate gene identification of downy mildew race 16 resistance in spinach

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Gehendra Bhattarai ◽  
Wei Yang ◽  
Ainong Shi ◽  
Chunda Feng ◽  
Braham Dhillon ◽  
...  
Keyword(s):  
Candidate Genes ◽  
Downy Mildew ◽  
Association Analysis ◽  
Spinacia Oleracea ◽  
Genotyping By Sequencing ◽  
Significant Snps ◽  
Snp Markers ◽  
Resistance Locus ◽  
Downy Mildew Resistance ◽  
Mildew Resistance

Abstract Background Downy mildew, the most devastating disease of spinach (Spinacia oleracea L.), is caused by the oomycete Peronospora effusa [=P. farinosa f. sp. spinaciae]. The P. effusa shows race specificities to the resistant host and comprises 19 reported races and many novel isolates. Sixteen new P. effusa races were identified during the past three decades, and the new pathogen races are continually overcoming the genetic resistances used in commercial cultivars. A spinach breeding population derived from the cross between cultivars Whale and Lazio was inoculated with P. effusa race 16 in an environment-controlled facility; disease response was recorded and genotyped using genotyping by sequencing (GBS). The main objective of this study was to identify resistance-associated single nucleotide polymorphism (SNP) markers from the cultivar Whale against the P. effusa race 16. Results Association analysis conducted using GBS markers identified six significant SNPs (S3_658,306, S3_692697, S3_1050601, S3_1227787, S3_1227802, S3_1231197). The downy mildew resistance locus from cultivar Whale was mapped to a 0.57 Mb region on chromosome 3, including four disease resistance candidate genes (Spo12736, Spo12784, Spo12908, and Spo12821) within 2.69–11.28 Kb of the peak SNP. Conclusions Genomewide association analysis approach was used to map the P. effusa race 16 resistance loci and identify associated SNP markers and the candidate genes. The results from this study could be valuable in understanding the genetic basis of downy mildew resistance, and the SNP marker will be useful in spinach breeding to select resistant lines.

scholarly journals Report of Leaf Spot of Spinach Caused by Stemphylium botryosum in Maryland and Delaware

Plant Disease ◽  
2001 ◽  
Vol 85 (11) ◽  
pp. 1209-1209 ◽  
Author(s):  
K. L. Everts ◽  
D. K. Armentrout
Keyword(s):  
Leaf Spot ◽  
Spinacia Oleracea ◽  
Disease Incidence ◽  
Deionized Water ◽  
Leaf Spot Disease ◽  
Pathogenicity Test ◽  
Fresh Market ◽  
Stemphylium Botryosum ◽  
Dark Regime ◽  
Research And Education

In October 2000, leaf spot symptoms were observed on spinach (Spinacia oleracea L. ‘Seven R’) at the University of Maryland Lower Eastern Shore Research and Education Center in Salisbury. In April 2001, a similar leaf spot disease was observed in two commercial spinach fields (cv. Vancouver) in Dorchester County, MD, and Sussex County, DE. Symptomatic plants occurred in foci, and overall disease incidence in the research and commercial fields was <10% of plants with lesions. However, low disease incidence may reduce the value of a spinach crop by requiring additional hand-sorting (fresh market) or lowering the grade (processing). Leaf spot lesions were small (0.2 to 0.7 cm), circular, tan, and papery and lacked visual signs of fungal infestation. Lesions resembled a new leaf spot of spinach reported in California (1) caused by Stemphylium botryosum Wallr. Plating surface-disinfested lesion margins on 0.25-strength potato dextrose agar consistently yielded S. botryosum. Single conidial cultures of three isolates were grown on V8 agar in a growth chamber with a 12 h light/dark regime at 21°C and were used for the pathogenicity test. Conidia were collected from 7-day-old colonies to test pathogenicity. Conidia were suspended in distilled water (1.1 × 105 conidia per milliliter), and sprayed on 4-week-old spinach plants (with four to six true leaves) of cvs. Seven R, Vancouver, and Melody. Noninoculated control plants were sprayed with deionized water. Plants were incubated for 72 h in a dew chamber (18°C, 9 to 15 h light/dark regime where dew formed during the dark periods) and then placed on a greenhouse bench (23°C) for 2 weeks. Plants that had been inoculated with any of the three isolates developed the aforementioned leaf spot lesions after 4 days in the greenhouse. Plants sprayed with deionized water were symptomless. One week after inoculation, more lesions were observed on ‘Seven R’ and ‘Vancouver’ than on ‘Melody’ (41, 39, and 1 lesion per plant, respectively; P< 0.0030), and the lesions were 1.5, 1.2, and 0.5 mm in diameter, respectively (P< 0.0001). S. botryosum was consistently reisolated from leaf spot lesions. The pathogenicity test was repeated with similar results. Isolates grown on V8 agar and incubated for ≈10 days produced conidia with mean dimensions of 31 × 19 μm. To our knowledge, this is the first report of leaf spot of spinach caused by S. botryosum in Maryland and Delaware. Reference: (1) S. T. Koike et al. Plant Dis. 85:126, 2001.

scholarly journals Genetic diversity and association analysis of leafminer (Liriomyza langei) resistance in spinach (Spinacia oleracea)

Genome ◽  
2016 ◽  
Vol 59 (8) ◽  
pp. 581-588 ◽  
Author(s):  
Ainong Shi ◽  
Beiquan Mou
Keyword(s):  
Association Analysis ◽  
Spinacia Oleracea ◽  
Insect Pest ◽  
Genetic Resistance ◽  
Genotyping By Sequencing ◽  
Complex Trait ◽  
Snp Markers ◽  
Minor Effect ◽  
Single Nucleotide ◽  
Wide Range

Leafminer (Liriomyza langei) is a major insect pest of many important agricultural crops, including spinach (Spinacia oleracea). Use of genetic resistance is an efficient, economic, and environment-friendly method to control this pest. The objective of this research was to conduct association analysis and identify single nucleotide polymorphism (SNP) markers associated with leafminer resistance in spinach germplasm. A total of 300 USDA spinach germplasm accessions were used for the association analysis of leafminer resistance. Genotyping by sequencing (GBS) was used for genotyping and 783 SNPs from GBS were used for association analysis. The leafminer resistance showed a near normal distribution with a wide range from 1.1 to 11.7 stings per square centimeter leaf area, suggesting that the leafminer resistance in spinach is a complex trait controlled by multiple genes with minor effect in this spinach panel. Association analysis indicated that five SNP markers, AYZV02040968_7171, AYZV02076752_412, AYZV02098618_4615, AYZV02147304_383, and AYZV02271373_398, were associated with the leafminer resistance with LOD 2.5 or higher. The SNP markers may be useful for breeders to select plants and lines for leafminer resistance in spinach breeding programs through marker-assisted selection.

scholarly journals Seedborne Cladosporium variabile and Stemphylium botryosum in Spinach

Plant Disease ◽  
2006 ◽  
Vol 90 (2) ◽  
pp. 137-145 ◽  
Author(s):  
Pablo Hernandez-Perez ◽  
Lindsey J. du Toit
Keyword(s):  
United States ◽  
Relative Humidity ◽  
Leaf Spot ◽  
Spinacia Oleracea ◽  
The United States ◽  
Causal Agent ◽  
Similar Species ◽  
Stemphylium Botryosum ◽  
Aerial Hyphae ◽  
Potential Difficulty

Assays of 77 spinach (Spinacia oleracea) seed lots produced in the United States, Denmark, the Netherlands, or New Zealand in 2000 to 2003 showed that Stemphylium botryosum, causal agent of Stemphylium leaf spot, was present in every lot, at a mean incidence of 29.1% per lot. Either Cladosporium variabile, causal agent of Cladosporium leaf spot, or the morphologically similar species C. macrocarpum, was present in 37 of the 77 lots, at a mean incidence of 1.8% per lot. Some seed isolates of S. botryosum and C. variabile proved pathogenic on spinach. Nonpathogenic isolates resembling C. variabile were identified as C. macrocarpum by the absence of torulose aerial hyphae. Pathogenic isolates of S. botryosum were also detected in each of 12 seed lots stored for up to 11 years at 4.4°C and 60% relative humidity. C. variabile or C. macrocarpum was detected in only 2 of the 11 lots, which had been stored for 3 and 8 years. Component seed assays demonstrated that S. botryosum and C. variabile (or C. macrocarpum) were internal and external in spinach seed. S. botryosum was detected in 5 to 76% of the embryos of five seed lots, but the two Cladosporium species were detected in only 0 to 1% of the embryos of these lots. This suggests greater potential difficulty at eradicating S. botryosum than C. variabile from infected spinach seed using seed treatments.

scholarly journals First Report of Stemphylium botryosum on Spinach in Texas

Plant Disease ◽  
2010 ◽  
Vol 94 (11) ◽  
pp. 1377-1377 ◽  
Author(s):  
J. D. Reed ◽  
J. E. Woodward ◽  
K. L. Ong ◽  
M. C. Black ◽  
L. A. Stein
Keyword(s):  
Leaf Spot ◽  
Spinacia Oleracea ◽  
Disease Incidence ◽  
Morphological Characteristics ◽  
Tween 80 ◽  
Growing Season ◽  
Control Treatment ◽  
Infected Leaf ◽  
First Report ◽  
Stemphylium Botryosum

During the 2009 to 2010 growing season, symptoms of an unknown leaf spot were observed on spinach (Spinacia oleracea L.) in production fields in southwest Texas. Approximately 500 ha were affected, especially cvs. Rakaia and Viceroy. Disease incidence was 30 and 2% for Rakaia and Viceroy, respectively. Diseased plants exhibited small (1 to 3 mm in diameter), tan, necrotic lesions with a circular to oval shape and were void of any signs of a pathogen. Symptomatic leaves were surface sterilized in 1.5% NaOCl for 1 min, rinsed with sterile water, and air dried. Leaf sections (~1 cm2) were cut and placed on acidified potato dextrose agar (APDA), or APDA supplemented with streptomycin (SAPDA). Fungal mycelia growing from the edges of infected leaf sections were transferred to PDA and incubated at 25°C with a 12-h/12-h light/dark cycle. After 14 days of incubation, dark brown mycelia giving rise to unbranched conidiophores bearing brown, deeply septate, ovoid conidia were observed. Conidia measured 16.8 to 27.3 × 13.1 to 19.6 μm. On the basis of these morphological characteristics, the fungus was identified as Stemphylium botryosum (3). Cultures were transferred to clarified V8 juice agar to obtain inoculum for pathogenicity tests. Eight-week-old plants (n = 20) of spinach cvs. Hybrid 310, Wintergreen, Ashley, and Rakaia were sprayed until runoff with a suspension containing 0.001% Tween 80 and 1 × 104 conidia/ml. Noninoculated plants served as a control treatment. Plants were placed in a growth chamber and incubated in the dark at 25°C and 95% relative humidity. Following 36 h of incubation, plants were transferred to a plastic enclosure and maintained at 23 ± 4°C. After 7 to 10 days, tan, oval-shaped lesions were observed on all inoculated spinach plants. All control plants, with the exception of Rakaia, failed to develop symptoms. Isolates of S. botryosum were recovered on SAPDA from symptomatic leaves, confirming Koch's postulates. Previous reports have shown that S. botryosum can be transmitted from infected seed (1), thus, additional plants of each cultivar (n = 36) were grown in the greenhouse to determine the potential for seedborne contamination. After 8 weeks, leaf spot symptoms identical to those observed on the original plants developed on 75% of the Rakaia plants, while symptom development on the other cultivars was negligible. Isolates of S. botryosum were only recovered from symptomatic Rakaia leaves. Similar field observations were made during the 2001 to 2002 growing season; however, attempts to isolate S. botryosum in that season were unsuccessful. Recent outbreaks of Stemphylium leaf spot have been reported in Arizona (4), California (3), Delaware and Maryland (2), and Washington (1). To our knowledge, this is the first report of S. botryosum on spinach in Texas. While the origin of inoculum causing the disease in Texas is unknown, S. botryosum may have been seedborne (2). The implementation within the past few years of very high density plantings of spinach (1.9 to 3.7 million seeds/ha) may lead to an increase in incidence and severity of this disease in Texas. References: (1) L. J. du Toit and M. L. Derie. Plant Dis. 85:920, 2001. (2) K. L. Everts and D. K. Armentrout. Plant Dis. 85:1209, 2001. (3) S. T. Koike et al. Plant Dis. 85:126, 2001. (4) S. T. Koike et al. Plant Dis. 89:1359, 2005.

scholarly journals First Report of Leaf Spot of Spinach Caused by Stemphylium botryosum in Arizona

Plant Disease ◽  
2005 ◽  
Vol 89 (12) ◽  
pp. 1359-1359 ◽  
Author(s):  
S. T. Koike ◽  
M. E. Matheron ◽  
L. J. du Toit
Keyword(s):  
Leaf Spot ◽  
Spinacia Oleracea ◽  
Morphological Characteristics ◽  
Fungal Growth ◽  
Geographic Area ◽  
First Report ◽  
Stemphylium Botryosum ◽  
Leaf Spots ◽  
Plant Disease Management ◽  
Seed Crops

During the winter (December through February) of 2003-2004, and again during 2004-2005, spinach (Spinacia oleracea) crops in the Yuma region of Arizona developed a foliar disease that previously had not been diagnosed in this geographic area. The problem was found on only a few acres and severity was low. The first symptoms consisted of round to oval leaf spots that were gray to olive green and visible from both adaxial and abaxial leaf surfaces. The spots were 3 to 6 mm in diameter but expanded up to as much as 10 mm. As disease progressed, leaf spots became tan and dry and papery in texture. Fungal growth was not observed on the spots. Isolations from the edges of surface-sterilized lesions onto V8 juice agar consistently resulted in fungal colonies. The fungus was identified as Stemphylium botryosum based on the following morphological characteristics of isolates incubated under fluorescent lights: dark green-to-brown mycelial growth, unbranched conidiophores with distinctly swollen apical cells that had dark bands, and dictyoconidia. The conidia were brown, ellipsoidal to ovoid, verrucose, borne singly, and measured 17 to 28 × 13 to 19 μm. To test pathogenicity, inoculum of each of five isolates (approximately 1 × 105 conidia/ml) was sprayed separately onto 20 to 25 plants each of spinach cvs. Whitney, Rushmore, Lion, Springfield, Nordic IV, and Unipak 144. Inoculated plants were incubated in a humidity chamber for 48 h and then maintained in a greenhouse (24 to 26°C). After 10 to 14 days, leaf spots resembling those seen in the field developed on all inoculated plants, and S. botryosum was reisolated from the spots. Control plants were similarly inoculated with water but did not develop symptoms. To our knowledge, this is the first report of leaf spot of spinach caused by S. botryosum in Arizona. The possibility of seedborne S. botryosum (3) may account for the development of this disease in winter spinach crops in this arid region. Leaf spot could be damaging to spinach grown in this region if rainfall is higher than normal, such as in 2004-2005. This disease has been reported in production spinach crops in California, Delaware, Florida, and Maryland (2,4) and in spinach seed crops in Washington (1). References: (1) L. J. du Toit and M. L. Derie. Plant Dis. 85:920, 2001. (2) K. L. Everts and D. K. Armentrout. Plant Dis. 85:1209, 2001. (3) P. Hernandez-Perez and L. J. du Toit. (Abstr.) Phytopathology 95:S41, 2005. (4) R. N. Raid and T. Kucharek. 2003 Florida Plant Disease Management Guide: Spinach. University of Florida, Gainesville, 2003.

Cladosporium variabile. [Descriptions of Fungi and Bacteria].

1995 ◽  
Author(s):  
J. C. David
Keyword(s):  
Geographical Distribution ◽  
Leaf Spot ◽  
Spinacia Oleracea ◽  
Wind Dispersal ◽  
Airborne Conidia

Abstract A description is provided for Cladosporium variabile. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Spinacia oleracea. Reports of this species from other hosts, such as Impatiens and Brassica, generally refer to infections by Cladosporium macrocarpum Preuss. DISEASE: Leaf-spot of spinach. GEOGRAPHICAL DISTRIBUTION: Asia: China (Shaanxi, Xinjiang), India. N. America: USA (MA, VA). Europe: Austria, Belgium, Denmark, Germany, Italy, Romania, Spain, UK. TRANSMISSION: By wind dispersal of airborne conidia.

scholarly journals Identification and characterization of maize lines resistant to leaf diseases

2019 ◽  
Vol 40 (2) ◽  
pp. 517
Author(s):  
Kaian Albino Corazza Kaefer ◽  
Adilson Ricken Schuelter ◽  
Ivan Schuster ◽  
Jonatas Marcolin ◽  
Eliane Cristina Gruszka Vendruscolo
Keyword(s):  
Genetic Diversity ◽  
Leaf Spot ◽  
Block Design ◽  
Snp Markers ◽  
Gray Leaf Spot ◽  
Leaf Blight ◽  
Yield Reduction ◽  
Northern Leaf Blight ◽  
Sources Of Resistance ◽  
White Leaf

Among the maize leaf diseases, white leaf spot, northern leaf blight, gray leaf spot, and southern rust are recognized not only by the potential for grain yield reduction but also by the widespread occurrence in the producing regions of Brazil and the world. The aim of this study was to characterize common maize lines for resistance to white leaf spot, northern leaf blight, gray leaf spot, and southern rust and suggest crosses based on the genetic diversity detected in SNP markers. The experiment was conducted in a randomized block design with three replications in order to characterize 72 maize lines. Genotypic values were predicted using the REML/BLUP procedure. These 72 lines were genotyped with SNP markers using the 650K platform (Affymetrix®) for the assessment of the genetic diversity. Genetic diversity was quantified using the Tocher and UPGMA methods. The existence of genetic variability for disease resistance was detected among maize lines, which made possible to classify them into three large groups (I, II, and III). The maize lines CD 49 and CD50 showed a good performance and can be considered sources of resistance to diseases. Therefore, their use as gene donors in maize breeding programs is recommended. Considering the information of genetic distance together with high heritability for leaf diseases, backcrossing of parent genotypes with different resistance levels, such as those of the lines CD49 x CD69 and CD50 x CD16, may result in new gene combinations, as they are divergent and meet good performances.

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