Alternaria species associated with early blight epidemics on tomato and other Solanaceae crops in northwestern Algeria

Bessadat, Nabahat; Berruyer, Romain; Hamon, Bruno; Bataillé‐Simoneau, Nelly; Benichou, Soumaya; Kihal, Mebrouk; Henni, Djamel Eddine; Simoneau, Philippe

doi:10.1007/s10658-016-1081-9

Cited by 61 publications

(66 citation statements)

References 30 publications

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“…This is the first report of DMI resistance in Alternaria isolates naturally occurring in field. A previous study reported that the baseline sensitivity of A. alternata , which is also in the Alternaria sect., from potato to difenoconazole was 0.14 μg mL −1 , similar to the baseline sensitivity of 0.17 μg mL −1 in the pathogen from pistachio orchards . In this study, we found that the mean EC 50 value of our isolates was 1.68 μg mL −1 , 10‐fold higher than the previous results .…”

Section: Discussionsupporting

confidence: 82%

“…Among them, the foliar disease of early blight, which causes premature defoliation and significant yield loss, is one of the major factors constraining potato production. This disease is caused by several species in Alternaria genus, including A. solani , A. grandis , A. alternata , A. longipes , A. tenuissima , A. dumosa , and A. arborescens etc., but dominant species recovered from diseased potato may vary substantially in space and time.…”

Section: Introductionmentioning

confidence: 99%

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Induced expression of CYP51 associated with difenoconazole resistance in the pathogenic Alternaria sect. on potato in China

Zhang

Zhou

Tian

et al. 2019

Pest Management Science

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BACKGROUND Early blight caused by Alternaria spp. is amongst the most important diseases in potato. Demethylation inhibitor (DMI) fungicides are widely used to control the disease but long‐term use may decrease its control efficacy due to fungicide resistance. This study investigated the occurrence of difenoconazole resistance in Alternaria spp. and molecular resistant mechanisms. RESULTS EC50 values of 160 isolates to difenoconazole ranged from 0.026 μg mL−1 to 15.506 μg mL−1 and the frequency of difenoconazole sensitivity formed a non‐normal distribution curve with a major and a minor peak. Isolates with EC50 values of 4.121 and 5.461 μg mL−1 were not controlled effectively at fungicide doses of 50 and 100 μg mL−1. Cross‐resistance was observed between DMI fungicides difenoconazole and propiconazole, but not between difenoconazole and other fungicide groups, including boscalid, iprodione, or carbendazim. The CYP51gene was 1673 bp encoding 525 amino acids in length and contained two introns. All sensitive and resistant isolates had the identical amino acid sequence of CYP51, with the exception of one resistant isolate carrying a mutation of R511W. A 6 bp insertion in the upstream region was observed in half of the resistant isolates. In the absence of propiconazole, the relative expression of CYP51 was not significantly different in sensitive and resistant isolates. In the presence of difenoconazole, expression of CYP51 gene was induced significantly in the DMI‐resistant isolates but not in the sensitive ones. CONCLUSION Induced expression of CYP51 in resistant isolates exposed to difenoconazole is an important determinant for DMI resistance in potato pathogens Alternaria sect. © 2019 Society of Chemical Industry

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Section: Discussionsupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Induced expression of CYP51 associated with difenoconazole resistance in the pathogenic Alternaria sect. on potato in China

Zhang

Zhou

Tian

et al. 2019

Pest Management Science

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“…More recently, Woudenberg et al [ 8 ] grouped several large-spored isolates including those from Solanaceae, Cucurbitaceae and Scrophulariaceae into a new species designated A. lineariae [ 8 ]. Large spore species were distinguished from small spore forms including A. alternata and A. arborescens ( A. alternata fsp lycopersici ), which have also been isolated from solanaceous plants and have been reported to cause EB-like symptoms in some situations [ 9 ]. To differentiate these closely-related large-spored Alternaria species, several morphological, molecular and chemotaxonomic approaches have been applied.…”

Section: Early Blightmentioning

confidence: 99%

Current Status of Early Blight Resistance in Tomato: An Update

Adhikari

Panthee

2017

IJMS

159

102

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Early blight (EB) is one of the dreadful diseases of tomato caused by several species of Alternaria including Alternaria linariae (which includes A. solani and A. tomatophila), as well as A. alternata. In some instances, annual economic yield losses due to EB have been estimated at 79%. Alternaria are known only to reproduce asexually, but a highly-virulent isolate has the potential to overcome existing resistance genes. Currently, cultural practices and fungicide applications are employed for the management of EB due to the lack of strong resistant cultivars. Resistance sources have been identified in wild species of tomato; some breeding lines and cultivars with moderate resistance have been developed through conventional breeding methods. Polygenic inheritance of EB resistance, insufficient resistance in cultivated species and the association of EB resistance with undesirable horticultural traits have thwarted the effective breeding of EB resistance in tomato. Several quantitative trait loci (QTL) conferring EB resistance have been detected in the populations derived from different wild species including Solanum habrochaites, Solanum arcanum and S. pimpinellifolium, but none of them could be used in EB resistance breeding due to low individual QTL effects. Pyramiding of those QTLs would provide strong resistance. More research is needed to identify additional sources of useful resistance, to incorporate resistant QTLs into breeding lines through marker-assisted selection (MAS) and to develop resistant cultivars with desirable horticultural traits including high yielding potential and early maturity. This paper will review the current understanding of causal agents of EB of tomato, resistance genetics and breeding, problems associated with breeding and future prospects.

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“…Alternaria tenuissima is an important global pathogen on a large variety of economically important crops, including broad bean, tomato, sunflower, potato, watermelon, and muskmelon (Rahman et al, 2002; Agamy et al, 2013; Wang et al, 2014; Zheng et al, 2015; Zhao et al, 2016a,b). The pathogen affects the above-ground parts of the crops, and is the causal agent of early blight, stem canker, and some fruit rots (Abdelfattah et al, 2016; Bessadat et al, 2017). Foliar diseases outbreaks caused by A. tenuissima are primarily epidemic and are especially devastating on tomato leaves (Agamy et al, 2013; Bessadat et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

The Population Genetics of Alternaria tenuissima in Four Regions of China as Determined by Microsatellite Markers Obtained by Transcriptome Sequencing

Yang

Chen

et al. 2018

Front. Microbiol.

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A total of 32,284 unigenes were obtained from the transcriptome of Alternaria tenuissima, a pathogenic fungus causing foliar disease in tomato, using next-generation sequencing (NGS) technology. In total, 24,670 unigenes were annotated using five databases, including NCBI non-redundant protein, Swiss-Prot, euKaryotic Orthologous Groups, Kyoto Encyclopedia of Genes and Genomes, and the Gene Ontology. A total of 1,140 simple sequence repeats were also identified for use as molecular markers. Sixteen of the simple sequence repeat loci were selected to study the population structure of A. tenuissima. A population genetic analysis of 191 A. tenuissima isolates, sampled from four geographic regions in China, indicated that A. tenuissima had a high level of genetic diversity, and that the selected simple sequence repeat markers could reliably capture the genetic variation. The null hypothesis of random mating was rejected for all four geographic regions in China. Isolation by distance was observed for the entire data set, but not within clusters, which is indicative of barriers to gene flow among geographic regions. The analyses of Bayesian and principal coordinates, however, did not separate four geographic regions into four separate genetic clusters. The different levels of historical migration rates suggest that isolation by distance did not represent a major biological obstacle to the spread of A. tenuissima. The potential epidemic spread of A. tenuissima in China may occur through the transport of plant products or other factors. The presented results provide a basis for a comprehensive understanding of the population genetics of A. tenuissima in China.

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Alternaria species associated with early blight epidemics on tomato and other Solanaceae crops in northwestern Algeria

Cited by 61 publications

References 30 publications

Induced expression of CYP51 associated with difenoconazole resistance in the pathogenic Alternaria sect. on potato in China

Induced expression of CYP51 associated with difenoconazole resistance in the pathogenic Alternaria sect. on potato in China

Current Status of Early Blight Resistance in Tomato: An Update

The Population Genetics of Alternaria tenuissima in Four Regions of China as Determined by Microsatellite Markers Obtained by Transcriptome Sequencing

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