Temporal and spatial dynamics of ascochyta blight caused by Ascochyta fabae speg. In faba bean fields in Tunisia

Youssef, Noura Omri Ben; Chaar, H.; Bessaidi, Zayneb; Halila, Imen; Jammezi, Noura; Mbazia, Ahlem; Kharrat, Mohamed; May, Christophe Le

doi:10.1007/s13313-020-00758-w

Cited by 1 publication

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“…The present study aimed to: (i) assess the frequency and the distribution of both A. fabae mating types among different locations in a larger Tunisian population to confirm the findings of Omri Ben Youssef et al. (2019) ; (ii) define the aggressiveness level and the morphological features of A. fabae isolates belonging to each mating type, and (iii) define if the membership to a mating type is associated with particular phenotypic traits or aggressiveness level.…”

Section: Introductionmentioning

confidence: 86%

“…The first studies dealing with A. fabae mating type distribution and involvement in genetic structure were those of Ozkilinc et al. (2015) and Omri Ben Youssef et al. (2019) who studied the role of mating types in the population diversity of Syrian and Tunisian collections of A. fabae .…”

Section: Introductionmentioning

confidence: 99%

“…(2019) who studied the role of mating types in the population diversity of Syrian and Tunisian collections of A. fabae . Omri Ben Youssef et al. (2019) showed that among their 240 Tunisian isolates MAT1-2 was more common in Tunisia than MAT1-1, and Tunisian populations had a skewed distribution (1:2 ratio) for MAT1-1:MAT1-2.…”

Section: Introductionmentioning

confidence: 99%

“…However, the presence of two mating types in the same region or field does not lead automatically to sexual recombination as revealed by Ozkilinc et al. (2015) and Omri Ben Youssef et al. (2019) .…”

Section: Introductionmentioning

confidence: 99%

“…A spatial lag would work on a lower scale than the field (plant and/or its different organs). Indeed, mating types may develop in the same field but on different plants or different organs (stem or leaf) making their recombination difficult as suggested by Omri Ben Youssef et al. (2019) .…”

Section: Introductionmentioning

confidence: 99%

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Didymella fabae Punith.: mating type occurrence, distribution and phenotyping of the anamorph Ascochyta fabae Speg. in Tunisia

Omri Ben Youssef,

Halila,

Mbazia

et al. 2023

Front. Plant Sci.

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Faba bean ascochyta blight, caused by Ascochyta fabae Speg. (teleomorph: Didymella fabae Punith.), is one of the most devastating diseases of the crop. It can cause yield losses that reach 95% in conducive weather conditions. Surveys were carried out in five regions of Tunisia: Beja, Bizerte, Jendouba, Kef and Tunis-Cap Bon. A total of 513 fungal isolates were collected from 2011 to 2013. A molecular characterization was conducted to identify the mating type of each individual using a mating type specific PCR. Results revealed that the two mating types MAT1-2 and MAT1-1 coexisted in all surveyed regions. An imbalance in favor of MAT1-2 was observed particularly in Bizerte and Jendouba regions (sex ratio was 18:85 and 32:80, respectively). Moreover, morphological and pathogenic characterization of 122 isolates among the collection revealed a significant variability in conidia type (one celled or two celled conidia) frequency, in conidia mean size and in aggressiveness toward Badii faba bean cultivar (incubation period, IP; percentage necrotic leaf area, S; and area under disease progression curve, AUDPC). A principal component analysis (PCA) performed on morphologically studied parameters (frequency of conidia cell number and conidia mean size) identified three groups of isolates based on morphological traits: one celled (1C) and two celled (2C) conidia rates, one celled and two celled conidia length and width (1L, 1W, 2L and 2W, respectively). A second PCA using aggressiveness parameters (IP: Incubation period, S1, S4 and S9: percentage of necrotic leaf area respectively 5, 20 and 45 days after inoculation) identified three distinct pathogenic groups: poorly pathogenic AG1, moderately pathogenic AG2 and highly pathogenic AG3. Morphological and pathogenic groups and mating type data were used to conduct a multiple factorial correspondence analysis (MFCA) which revealed a correlation between the variables studied. Five groups were identified, each associated with a morphological and pathogenic trait and mating type. The most pathogenic group belonged to MAT1-2 suggesting that in locations where MAT1-2 is prevalent the epidemic risk is more important.

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Section: Introductionmentioning

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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