Detection and Biological Characteristics of Alternaria alternata Resistant to Difenoconazole from Paris polyphylla var. chinensis, an Indigenous Medical Herb

Plant Disease ◽  
2020 ◽  
Author(s):  
Chunxia Sun ◽  
Fengjie Li ◽  
Mengdi Wei ◽  
Zengxu Xiang ◽  
Changjun Chen ◽  
...  
Keyword(s):  
Sequence Alignment ◽  
Growth Rates ◽  
Alternaria Alternata ◽  
Mycelial Growth ◽  
Black Spot ◽  
Cross Resistance ◽  
Yield Losses ◽  
Resistant Genotype ◽  
Paris Polyphylla ◽  
Resistant Genotypes

Black spot caused by Alternaria alternata (BSAA) is one of the most common diseases of Paris polyphylla var. chinensis (PPVC), causing yield losses in China. Demethylation-inhibitors (DMIs) have been used to control this disease in China for decades. Some farmers in complained about the decreased efficacy of DMIs against BSAA. The objective of this study was to detect and characterize the resistance of A. alternata against difenoconazole from PPVC during 2018. Of the 22 isolates of A. alternata obtained from Sichuan Province in the southwest of China, 20 were resistant to difenoconazole. Mycelial growth rates and sporulation of the difenoconazole resistant (DfnR) isolates were not different from those of the difenoconazole sensitive (DfnS) isolates. No cross-resistance between difenoconazole and tebuconazole, or propiconazole was observed. Mutations were identified at AaCYP51 of DfnR isolates based on the sequence alignment of the DfnR and DfnS isolates. All the mutations could be divided into three resistant genotypes, Ⅰ (K715R + Y781C), Ⅱ (K715R + D1140G + T1628A) and Ⅲ (no mutation). Docking total score of the DfnS isolates was 5.6020, higher than the resistant genotype Ⅰ (4.4599), or the resistant genotype Ⅱ (3.8651), suggesting that the DMI-resistance of A. alternata may be caused by the decreased affinity between AaCYP51 and difenoconazole.

Detection and fitness of dicarboximide-resistant isolates of Alternaria alternata from Dendrobium officinale, a Chinese indigenous medicinal herb.

Plant Disease ◽  
2020 ◽  
Author(s):  
Weicheng Zhao ◽  
Chunxia Sun ◽  
Lingling Wei ◽  
Wenchan Chen ◽  
Bingran Wang ◽  
...  
Keyword(s):  
Alternaria Alternata ◽  
Mycelial Growth ◽  
Medicinal Herb ◽  
Dendrobium Officinale ◽  
Cross Resistance ◽  
Resistance Pattern ◽  
Amino Acid Sequence Alignment ◽  
Group I ◽  
Black Spots ◽  
Significant Difference

Black spots caused by Alternaria Alternata poses a sever threat to the industry of Dendrobium officinale, a Chinese indigenous medicinal herb. Dicarboximide fungicides (DCFs) are intensively used to control this disease for decades in China, and offering excellent efficacy. The resistance of phytopathogenic pathogens against DCFs are reportedly selected in fields; however, the DCF-resistance of A. alternata from D. officinale is not well understood. The low procymidone-resistant (ProLR) isolates of A. alternata were detected in the commercial orchards of D. officinale in China in 2018 and biochemically characterized in this study. The result showed that the low procymidone-resistant (ProLR) isolates were selected in the commercial orchards with the resistance frequency of 100 %, and no significant difference in mycelial growth, sporulation and virulence was observed among the ProLR and ProS isolates. A positive cross-resistance pattern was exhibited between procymidone and iprodione. Amino acid sequence alignment results of AaOS-1 from the tested isolates showed that all the ProLR genotypes could be categorized into two groups, including group I (mutations at AaOs-1) and group II (no mutation). On procymidone (5.0 μg/ml) treatment condition, the AaOs-1 expression levels increased in the ProS isolates ranged from 2.94~3.69 folds higher than those on procymidone-free condition, while the AaOs-1 expressions of the ProLR isolates were significantly lower than those in the ProS isolates on the same conditions. The data indicated that the mutations at AaOs-1 are involved in the DCF-resistance of A. alternata selected in the D. officinale orchards.

scholarly journals Studies of alternaria black spot disease of pomegranate caused by Alternaria alternata in Punjab

2017 ◽  
Vol 9 (1) ◽  
pp. 156-161 ◽  
Author(s):  
Adesh Kumar ◽  
Tanjeet Singh Chahal ◽  
Mandeep Hunjan Singh Singh ◽  
Harminder Kaur ◽  
Roomi Rawal
Keyword(s):  
Alternaria Alternata ◽  
Mycelial Growth ◽  
Disease Incidence ◽  
Black Spot ◽  
Economic Losses ◽  
Group Method ◽  
Research Station ◽  
Toxic Reaction ◽  
Pair Group ◽  
Highly Virulent

Alternaria black spot of pomegranate caused by Alternaria alternata pose significant economic losses in India as it reduce the crop yield. Farm survey was undertaken at Punjab Agricultural University, Pomegranate Research Block, Fruit Research Station, Jallowal- Lesriwal Jalandhar during 2015. Among all the five cultivars highest disease incidence (70%) and severity (30%) was registered in cultivar Bhagwa. Twenty two isolates of A. alternata were recovered from infected fruits and clustered using UPGMA (unweighted pair group method with arithmetic averages) on the basis of disease score produced in five cultivars (Ganesh, Ruby, Bhagwa, Jyoti and Mridula). It was revealed that five isolates namely AL14, AL15, AL20, AL21 and AL22 were highly virulent on almost all the pomegranate cultivars. Two cultivars viz. Bhagwa and Mridula were found to be most susceptible as 45.45 % isolates were found to be highly virulent on them.Thein vitro antifungal effects of the six fungicides on mycelial growth were investigated. Based on the inhibition of mycelial growth, all the fungicides showed most toxic reaction with 50% effective concentrations (EC50) of < 1 ppm. However, they varied in EC90 values. 10 ppm cocentration of Tilt (azole group) showed 90% effective concentration (EC90). Folicur also showed approximately same results as Tilt while EC90 value of Natio and SAAF was <25 ppm and > 20 ppm. However, two fungicides namely Dithane Z-78 and Bavistin showed less toxicity against Alternaria alternata as compared to other with EC90 value at concentrations <50 ppm and > 25 ppm. Azole group fungicides (Tilt and Folicur) were found most effective to inhibit the pathogen growth.

scholarly journals Biochemical and molecular characterization of Alternaria alternata isolates highly resistant to procymidone from broccoli and cabbage

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Bingran Wang ◽  
Tiancheng Lou ◽  
Lingling Wei ◽  
Wenchan Chen ◽  
Longbing Huang ◽  
...  
Keyword(s):  
Alternaria Alternata ◽  
Single Point ◽  
Sodium Dodecyl ◽  
Cross Resistance ◽  
Molecular Characteristics ◽  
Single Point Mutation ◽  
Wide Range ◽  
Significant Difference ◽  
Leaf Blights ◽  
High Level

AbstractAlternaria alternata, a causal agent of leaf blights and spots on a wide range of hosts, has a high risk of developing resistance to fungicides. Procymidone, a dicarboximide fungicide (DCF), has been widely used in controlling Alternaria leaf blights in China for decades. However, the resistance of A. alternata against DCFs has rarely been reported from crucifer plants. A total of 198 A. alternata isolates were collected from commercial fields of broccoli and cabbage during 2018–2019, and their sensitivities to procymidone were determined. Biochemical and molecular characteristics were subsequently compared between the high-level procymidone-resistant (ProHR) and procymidone-sensitive (ProS) isolates, and also between ProHR isolates from broccoli and cabbage. Compared with ProS isolates, the mycelial growth rate, sporulation capacity and virulence of most ProHR isolates were reduced; ProHR isolates displayed an increased sensitivity to osmotic stresses and a reduced sensitivity to sodium dodecyl sulfate (SDS); all ProHR isolates showed a reduced sensitivity to hydrogen peroxide (H2O2) except for the isolate B102. Correlation analysis revealed a positive cross-resistance between procymidone and iprodione, or fludioxonil. When treated with 10 μg/mL of procymidone, both mycelial intracellular glycerol accumulations (MIGAs) and relative expression of AaHK1 in ProS isolates were higher than those in ProHR isolates. Sequence alignment of AaHK1 from ten ProHR isolates demonstrated that five of them possessed a single-point mutation (P94A, V612L, E708K or Q924STOP), and four isolates had an insertion or a deletion in their coding regions. No significant difference in biochemical characteristics was observed among ProHR isolates from two different hosts, though mutations in AaHK1 of the cabbage-originated ProHR isolates were distinct from those of the broccoli-originated ProHR isolates.

Sensitivity of C. fructicola and C. siamense of peach in China to multiple classes of fungicides and characterization of pyraclostrobin-resistant isolates

Plant Disease ◽  
2021 ◽  
Author(s):  
Hafiz Muhammad Usman ◽  
Qin Tan ◽  
Mohammad Mazharul Karim ◽  
Muhammad Adnan ◽  
Weixiao Yin ◽  
...  
Keyword(s):  
High Resistance ◽  
Mycelial Growth ◽  
Management Strategies ◽  
Cross Resistance ◽  
Qoi Fungicides ◽  
Quinone Outside Inhibitor ◽  
Dmi Fungicides ◽  
Colletotrichum Gloeosporioides Species Complex ◽  
Cyt B Gene

Anthracnose, mainly caused by Colletotrichum gloeosporioides species complex including C. fructicola and C. siamense, is a devastating disease of peach. The chemical control has been widely used for years and management failures have increased towards commonly used fungicides. Therefore, screening of sensitivity of Colletotrichum spp. to fungicides with different modes of action is needed to make proper management strategies for peach anthracnose. In this study, sensitivity of 80 isolates of C. fructicola and C. siamense was screened for pyraclostrobin, procymidone, prochloraz and fludioxonil based on mycelial growth inhibition at discriminatory doses. Results showed that C. fructicola and C. siamense isolates were highly resistant to procymidone and fludioxonil with 100% resistance frequencies to both fungicides, but sensitive to prochloraz, i.e., no resistant isolates were found. For pyraclostrobin, 74% of C. fructicola isolates showed high resistance and 26 % were low resistant, all of the C. siamense isolates were low resistant. No positive cross-resistance was observed between pyraclostrobin and azoxystrobin, even they are members of the same quinone outside inhibitor (QoI) fungicide group, and between pyraclostrobin and non-QoIs. Resistant isolates to QoI fungicides were evaluated for the fitness penalty. Results showed that no significant differences except for mycelial growth rates were detected between highly resistant and low-resistant isolates of C. fructicola. Molecular characterization of Cyt b gene revealed that the G143A point mutation was the determinant of the high resistance in C. fructicola. This study demonstrated the current resistance status of C. fructicola and C. siamense to different fungicides and their future perspectives. Demethylation inhibitor (DMI) fungicides are the best option among different chemicals to control peach anthracnose in China.

scholarly journals AVALIAÇÃO DO REAL POTENCIAL INIBIDOR DE EXTRATOS ETANÓLICOS DE Ottonia martiana SOBRE Cylindrocladium spathulatum E Botrytis cinerea

FLORESTA ◽  
2013 ◽  
Vol 43 (2) ◽  
pp. 225
Author(s):  
Miriam Machado Cunico ◽  
Celso Garcia Auer ◽  
Marlon Wesley Machado Cunico ◽  
Obdulio Gomes Miguel ◽  
Patricio Peralta Zamora ◽  
...  
Keyword(s):  
Factorial Design ◽  
Botrytis Cinerea ◽  
Mycelial Growth ◽  
Black Spot ◽  
Gray Mold ◽  
Causal Agent ◽  
In Vitro Testing ◽  
Ethanolic Extracts ◽  
Antifungal Potential

 Extratos etanólicos de anestesia, Ottonia martiana Miq., foram reavaliados quanto à inibição do crescimento micelial dos fungos Cylindrocladium spathulatum (pinta-preta da erva-mate) e Botrytis cinerea (mofo-cinzento do eucalipto), por meio do planejamento fatorial. A ocorrência de decomposição de bioativos no processo de autoclavagem também foi investigada, por meio de teste de eficiência de extratos filtrados (filtro Millipore) e esterilizados (autoclave) no controle dos fitopatógenos, nas concentrações de 1, 10, 100 e 1000 ppm. Os extratos etanólicos filtrado e esterilizado inibiram o crescimento micelial dos fungos e foram mais ativos frente a B. cinerea.O extrato filtrado exibiu maior potencial antifúngico que o extrato esterilizado. O processo de esterilização por autoclavagem causou pequena decomposição dos bioativos presentes no extrato de anestesia.Palavras-chave: Anestesia; mofo-cinzento; pinta-preta. Abstract Fungitoxic potential of ethanolic extracts of anestesia in the control of phytopathogenic diseases. The antifungal potential of anestesia, Ottonia martiana Miq. was reassessed by factorial design, in vitro testing of fungal mycelial growth compared to the pathogenic isolates Cylindrocladium spathulatum, causal agent of black spot onyerba mate, and Botrytis cinerea causal agent of gray-mold on eucalypts. Occurrence of decomposition of bioactive of the autoclaving process was investigated using foliar detached test compared to the pathogens (1000 ppm). Ethanolic extracts - EBEtOH (filtered and autoclaved) inhibited the mycelial growth of C. spathulatum and B. cinerea (1000 ppm) and were more pronounced against B. cinerea (43.6 % and 68.9 %). EBEtOH filtered (0.22 µm) presented higher activity than EBEtOH autoclaved (C. spathulatum: 52.8 % and 43.6 %, B. cinerea: 68.9 % and 43.6 %), suggesting little decomposition ofbioactive after autoclaving. EBEtOH filtrate presented potential inhibition of 28 % in eucalypt leaves against B. cinerea.  Keywords: Ottonia martiana; black spot; gray-mold.

scholarly journals Alternaria Late Blight (Alternaria alternata) Resistance in Pistachio (Pistacia vera) and Selection of Resistant Genotypes

2001 ◽  
Vol 126 (4) ◽  
pp. 481-485 ◽  
Author(s):  
Chih-Cheng T. Chao ◽  
Dan E. Parfitt ◽  
Themis J. Michailides
Keyword(s):  
Late Blight ◽  
Alternaria Alternata ◽  
Pistacia Vera ◽  
Narrow Sense ◽  
Cultivar Selection ◽  
Resistant Genotypes ◽  
Selection Of

Pistachio (Pistacia vera L.) progeny were evaluated at two locations in California for resistance to alternaria late blight caused by Alternaria alternata (Fries) Keissler in 1995 and 1997. Large differences in alternaria late blight infection among seedlings were observed. Narrow sense heritabilities based on half-sib analysis of 20 open pollinated families were 0.48 and 0.11 at Kearney Agricultural Center in 1995 and 1997, respectively, and 0.56 and 0.54 at the Wolfskill Experimental Orchard near Davis in 1995 and 1997, respectively. Differences among families to alternaria late blight infection were highly significant and associated with the female parents. Fifty-eight highly resistant seedlings were identified for future cultivar selection efforts.

scholarly journals First Report of Alternaria Leaf Spot of Almond Caused by Species in the Alternaria alternata Complex in California

Plant Disease ◽  
2001 ◽  
Vol 85 (5) ◽  
pp. 558-558 ◽  
Author(s):  
B. L. Teviotdale ◽  
M. Viveros ◽  
B. Pryor ◽  
J. E. Adaskaveg
Keyword(s):  
Alternaria Alternata ◽  
Leaf Spot ◽  
Disease Incidence ◽  
Prunus Dulcis ◽  
Leaf Spot Disease ◽  
Yield Losses ◽  
Mature Leaves ◽  
Branching Chains ◽  
Paper Towels ◽  
Industry Conference

A new leaf spot disease of almond (Prunus dulcis [Mill.] D. Webb) was observed in California in the late 1980s and was first associated with severe defoliation in the mid-1990s (1). Orchards in areas with frequent summer dews, high humidity, and little air movement sustained severe defoliation, resulting in yield losses often exceeding 50%. Symptoms occur only on leaf blades in late spring and summer. Lesions develop as small, circular, tan spots 1 to 3 mm in diameter that may enlarge to 5 to 20 mm in size. Semicircular lesions frequently develop along the leaf margins and tips. The centers of mature lesions become black with fungal sporulation. The fungi isolated from the margins of sporulating and non-sporulating lesions were identified as three species in the Alternaria alternata complex: A. alternata, A. arborescens, and A. tenuissima (2,3). Cultures grown in the dark on potato dextrose (PDA) or potato-carrot agar are grayish white to olivacious green in the former two species and dark gray and wooly in the latter species. On 5% PDA, cultures of all three species produced catenulate dictyospores that were granular to punctate (-verrucose), pale yellowish to brown or black, and had visible apical and basal pores. Conidial morphology depended on chain position; apical conidia ranged from ovoid to ellipsoid, whereas basal conidia were elliptical to obclavate. Average conidial dimensions of A. alternata and A. arborescens ranged from 20 to 28 × 8 to 10 μm. Conidia of A. alternata were produced in acropetal succession in branching chains on single, short suberect conidiophores. A. arborescens produced conidia similarly but mostly in dichotomously branching chains on short to long conidiophores. Average conidial dimensions of A. tenuissima ranged from 20 to 34 × 8 to 12 μm and they were produced in simple chains with one or two branches forming occasionally. In preliminary studies, the optimum temperature for mycelial growth on PDA for all three species ranged from 24 to 28°C. Fifty mature leaves on each of four 7- or 8-year-old almond cv. Butte trees were inoculated at 2- to 3-week intervals from mid-spring through summer in 1999 and 2000. Leaves were sprayed with aqueous suspensions containing 105 conidia per milliliter for one isolate each of A. alternata and A. arborescens and two isolates of A. tenuissima or with sterile distilled water. The shoots were covered for 72 h with plastic-lined brown paper bags containing wet paper towels. Leaves were examined for infection after 7 and 14 days. All isolates were pathogenic and produced non-sporulating lesions similar to those observed in natural infections. No symptoms were observed on noninoculated control plants. Disease incidence was low (<15%) until late June 1999 and July 2000. Inoculations in summer produced increasingly more infections, reaching incidences of 40 to 52% in September 1999 and 18 to 80% in August 2000. References: (1) J. E. Adaskaveg. 1994. Pages 5–7 in Proceedings of the 22nd Annual Almond Industry Conference. 1994. (2) J. Rotem. 1994. The genus Alternaria. Biology, Epidemiology, and Pathogenicity. APS Press, St. Paul, MN. (3) E. G. Simmons. Mycotaxon 70:325–369, 1999.

scholarly journals Screening of French Bean (Phaseolus vulgaris L.) Genotypes against Alternaria Leaf Spot Caused by (Alternaria alternata) under Dryland Conditions of Kashmir

2021 ◽  
pp. 25-30
Author(s):  
Sabiya Bashir ◽  
Mohammad Najeeb Mughal ◽  
Zahida Rashid ◽  
Shabeena Majid ◽  
Sabeena Naseer ◽  
...  
Keyword(s):  
Alternaria Alternata ◽  
Leaf Spot ◽  
Disease Incidence ◽  
French Bean ◽  
Phaseolus Vulgaris L ◽  
Dryland Agriculture ◽  
Disease Reaction ◽  
The Mean ◽  
Selection For ◽  
Resistant Genotypes

Sixty-three genotypes of  french bean was screened against leaf spot (Alternaria  alternata) in sick plots at Research Farm of Dryland Agriculture Research Srinagar, Rangreth during  Kharif  2018 and 2019. The highest mean disease incidence ranged from 0.00 to 85.00 per cent  with  the mean disease intensity ranged from 0.00 to 53.26 per cent .One genotype namely  ‘Local Pulwama’ was highly susceptible in their disease reaction. Among the screened germplasm, ‘Highly Resistant’ genotypes was SKU-R-601, SKUA-R-105, SKU-R-927, DARS-25, DARS-66, DARS-R-615,  while as ‘Susceptible’ genotypes was  DARS-8, DARS-12,  DARS-11, SKUAST-R-155, SKU-R-928, DARS-7, DARS-R-4, Bhaderwah (L),  Local  Kupwara black and Raj Jawala. Local Pulwama was found to be a highly susceptible (HS) genotype.  Twenty nine genotypes namely., DARS-16, DARS-9, DARS-54, DARS-39, VL-125, DARS-63, ENTO-504, SKUAST-204,SKU-R-925, DARS-60, DARS-109, DARS-43, DARS-44, SKU-R-23, DARS-4, DARS-74, SKU-R-105, DARS-40, DARS-23, DARS-18, SKU-R-71, WB-341, SKU-R-605, Uri local, Shopian (L), SKU-R-23, DARS-71, SSGB-729, DARS-R-19 showed resistant reaction to disease. The selection for resistance was based on the reaction of varieties on leaves.

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