Characterization of baseline sensitivity and resistance risk of Colletotrichum gloeosporioides complex isolates from strawberry and grape to two demethylation-inhibitor fungicides, prochloraz and tebuconazole

2014 ◽  
Vol 43 (6) ◽  
pp. 605-613 ◽  
Author(s):  
X. F. Xu ◽  
T. Lin ◽  
S. K. Yuan ◽  
D. J. Dai ◽  
H. J. Shi ◽  
...  
Plant Disease ◽  
2018 ◽  
Vol 102 (5) ◽  
pp. 1015-1024 ◽  
Author(s):  
Oliul Hassan ◽  
Jong Yeob Jeon ◽  
Taehyun Chang ◽  
Jun Sung Shin ◽  
Nam Kwon Oh ◽  
...  

Anthracnose is a major disease of persimmon in the pre- and postharvest phase. Several species of Colletotrichum (Colletotrichum gloeosporioides, C. acutatum, and C. horii) have been reported as causal agents of persimmon anthracnose in South Korea. In this study, a collection of 50 isolates associated with persimmon anthracnose were collected from Sangju (n = 25) and Cheongdo-gun (n = 25), South Korea. The morphological characteristics of all 50 Colletotrichum isolates were similar, and it was difficult to identify the isolates to the species level. A subsample of eight isolates was characterized phylogenetically to ascertain species. BLAST search and phylogenetic analysis of the internal transcribed spacer (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and actin (ACT) genes revealed two species: C. horii as well as a previously unreported persimmon anthracnose causal agent C. siamense. C. siamense isolates were confirmed again by phylogenetic analysis of the ITS, ACT, GAPDH, calmodulin, and Apn2-Mat1-2 intergenic spacer partial mating type genes. Koch’s postulates for C. horii and C. siamense were fulfilled, confirming the pathogenicity of the two species in persimmon fruit. Morphological characteristics (colony morphology and size and shape of conidia and appressoria) from two representative isolates support results of the phylogenetic analysis and match those of previous descriptions of C. horii and C. siamense.


2021 ◽  
Author(s):  
Mengze Gao ◽  
Miting Wan ◽  
Liyun Yang ◽  
Meng Zhao ◽  
Xiaojin Liu ◽  
...  

Mycologia ◽  
2012 ◽  
Vol 104 (2) ◽  
pp. 396-409 ◽  
Author(s):  
Diogo Nuno Silva ◽  
Pedro Talhinhas ◽  
Vítor Várzea ◽  
Lei Cai ◽  
Octávio Salgueiro Paulo ◽  
...  

Plant Disease ◽  
2021 ◽  
Author(s):  
Gangming Zhan ◽  
Fan Ji ◽  
Jun Zhao ◽  
Yue Liu ◽  
Aihong Zhou ◽  
...  

Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a destructive disease of wheat that seriously threatens production safety in wheat-producing areas worldwide. In China, the disease has been largely controlled with fungicide triadimefon. Although high levels of fungicide resistance in other fungal pathogens have been reported, failure to control Pst with any fungicides has seldomly been reported and fungicide sensitivity of Pst has not been evaluated in China. The distribution of triadimefon-resistant Pst isolates was investigated in the present study. The baseline sensitivity of 446 Pst isolates across the country to triadimefon was determined, and the concentration for 50% of maximal effect (EC50) showed a unimodal distribution curve, with a mean value of 0.19 μg mL-1. The results indicated a wide range of sensitivity to triadimefon, with more insensitive isolates collected from Pst winter-increasing areas and northwest over-summering areas, whereas more sensitive isolates were collected from southwest over-summering areas and epidemic areas of Xinjiang and Tibet. The majority of the tested Pst isolates were sensitive to triadimefon; only 6.79% had developed varying degrees of resistance. Characterization of parasitic fitness revealed that the triadimefon-resistant isolates exhibited strong adaptive traits in urediniospore germination rate, latent period, sporulation intensity, and lesion expansion rate. Positive cross-resistance was observed between triadimefon and tebuconazole or hexaconazole, but not between pyraclostrobin or flubeneteram. The point mutation Y134F in the 14α-demethylase enzyme (CYP51) was detected in triadimefon-resistant isolates. A molecular method (Kompetitive Allele Specific PCR) was established for the rapid detection of Y134F mutants in the Pst population. Two genotypes with one point mutation Y134F conferred resistance to triadimefon in Pst. The risk of resistance to triadimefon in Pst may be low to moderate. This study provided important data for establishment of high throughput molecular detection methods, fungicide resistance risk management, and the development of new target fungicides.


Author(s):  
Juan Diego Valenzuela Cobos ◽  
René Oscar Rodríguez-Grimón ◽  
Ana Grijalva-Endara ◽  
Raúl Marcillo-Vallejo ◽  
Onay Adonys Mercader-Camejo

Colletotrichum gloeosporioides (GC003) and Rhizopus stolonifer (RS001) were cultivated in two different liquid culture media: LC1 (glucose 40 g L-1, yeast extract 3 g L-1 and tryptone peptone 2 g L-1) and LC2 (glucose 40 g L-1, yeast extract 3 g L-1 and tryptone peptone 10 g L-1) for the production of mycelial biomass and exopolysaccharides (EPS). By using the liquid culture (LC2) under pH of 4.5 presented the highest biomass content (15.73 g L-1) in the propagation of Rhizopus stolonifer. The highest production of exopolysaccharides (1.74 g L-1) was obtained by the liquid culture (LC2) under pH of 4.5 in the cultivation of Colletotrichum gloeosporioides. The results presented that the production of biomass and exopolysaccharides (EPS) is directly related with the pHs values and the strain used in the cultivation.


2006 ◽  
Vol 96 (5) ◽  
pp. 542-548 ◽  
Author(s):  
Marcel Maymon ◽  
Aida Zveibil ◽  
Shimon Pivonia ◽  
Dror Minz ◽  
Stanley Freeman

Sixty-four isolates of Colletotrichum gloeosporioides were isolated from infected Limonium spp. cultivated in 12 different locations in Israel. All isolates were identified as belonging to the C. gloeosporioides complex by species-specific primers. Of these isolates, 46 were resistant to benomyl at 10 μg/ml and 18 were sensitive to this concentration of fungicide. Based on arbitrarily primed polymerase chain reaction of all isolates and internal transcribed spacer-1 sequence analyses of 12 selected isolates, the benomyl-resistant and -sensitive populations belong to two distinct genotypes. Sequence analyses of the β-tubulin genes, TUB1 and TUB2, of five sensitive and five resistant representative isolates of C. gloeosporioides from Limonium spp. revealed that the benomyl-resistant isolates had an alanine substitute instead of a glutamic acid at position 198 in TUB2. All data suggest that the resistant and sensitive genotypes are two independent and separate populations. Because all Limonium plant propagation material is imported from various geographic regions worldwide, and benomyl is not applied to this crop or for the control of Colletotrichum spp. in Israel, it is presumed that plants are bearing quiescent infections from the points of origin prior to arrival.


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