Production and viability of sclerotia from fungicide‐resistant and fungicide‐sensitive isolates of Botrytis cinerea, B. elliptica and B, tulipae

Hsiang, Tom; Chastagner, Gary A.

doi:10.1111/j.1365-3059.1992.tb02459.x

Cited by 24 publications

(4 citation statements)

References 19 publications

(23 reference statements)

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“…Similarly, the resistant BC isolates showed slower growth rates (6.4 mm d −1 ) at 91% of the growth rate of the non‐BC isolates (7.0 mm d −1 ). This is in line with previous research, which found that isolates of Botrytis species with decreased sensitivity to iprodione grew at a slower rate than sensitive isolates (Hsiang and Chastagner, 1991), and that sclerotia of iprodione‐resistant isolates of Botrytis elliptica showed lower survival rates than sensitive isolates (Hsiang and Chastagner, 1992). Raposo et al (2000) reported decreased sclerotia survival for iprodione‐resistant Botrytis cinerea isolates compared with sclerotia of sensitive isolates; however, they did not see differences in mycelial growth.…”

Section: Discussionsupporting

confidence: 92%

Resistance to Dicarboximide Fungicides in a Canadian Population of Microdochium nivale

Gourlie

Hsiang

2017

Intl Turfgrass Soc Res J

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Isolates of Microdochium nivale suspected of resistance to iprodione [3‐(3,5‐Dichlorophenyl)‐N‐isopropyl‐2,4‐dioxoimidazolidine‐1‐carboxamide] were collected from a golf course in Victoria, British Columbia (BC), Canada, in Fall 2015. The 9 BC isolates and 12 other reference isolates from around the world were tested with four concentrations of iprodione: 0, 1, 10, and 100 μg mL−1. The BC isolates showed a half maximal effective concentration (EC50) range of 14.2 to 40.8 μg mL−1 with a mean of 24.2 μg mL−1, while the non‐BC isolates showed an EC50 range of 1.2 to 4.3 μg mL−1 with a mean of 1.9 μg mL−1. The yielded resistance factor (EC50 resistant/EC50 sensitive) of 12.7 implies that these BC isolates have been selected for reduced sensitivity to iprodione. This level of resistance may be responsible for the reduced efficacy, particularly the observed reduced interval of control, but further research is needed to assess this. A test of >100 isolates of M. nivale from a worldwide collection using a discriminatory concentration of 10 μg mL−1 of iprodione showed four isolates with similar levels of reduced sensitivity, but these were the only isolates from their respective populations.

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Section: Discussionsupporting

confidence: 92%

Resistance to Dicarboximide Fungicides in a Canadian Population of Microdochium nivale

Gourlie

Hsiang

2017

Intl Turfgrass Soc Res J

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“…3 , sclerotia were observed after 10 dpi for the Δ bcfet1 mutant but not the B05.10 wild-type strain. These structures are required for overwintering, enabling the fungi to survive unfavorable conditions during extended periods of time when temperatures and/or nutrient availability are low ( 46 ). This observation is consistent with a mutant strain bearing a reduced/impaired acquisition of iron.…”

Section: Resultsmentioning

confidence: 99%

Defects in the Ferroxidase That Participates in the Reductive Iron Assimilation System Results in Hypervirulence in Botrytis Cinerea

Vasquez-Montaño

Hoppe

Vega

et al. 2020

mBio

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The plant pathogen Botrytis cinerea is responsible for gray-mold disease, which infects a wide variety of species. The outcome of this host-pathogen interaction, a result of the interplay between plant defense and fungal virulence pathways, can be modulated by various environmental factors. Among these, iron availability and acquisition play a crucial role in diverse biological functions. How B. cinerea obtains iron, an essential micronutrient, during infection is unknown. We set out to determine the role of the reductive iron assimilation (RIA) system during B. cinerea infection. This system comprises the BcFET1 ferroxidase, which belongs to the multicopper oxidase (MCO) family of proteins, and the BcFTR1 membrane-bound iron permease. Gene knockout and complementation studies revealed that, compared to the wild type, the bcfet1 mutant displays delayed conidiation, iron-dependent sclerotium production, and significantly reduced whole-cell iron content. Remarkably, this mutant exhibited a hypervirulence phenotype, whereas the bcftr1 mutant presents normal virulence and unaffected whole-cell iron levels and developmental programs. Interestingly, while in iron-starved plants wild-type B. cinerea produced slightly reduced necrotic lesions, the hypervirulence phenotype of the bcfet1 mutant is no longer observed in iron-deprived plants. This suggests that B. cinerea bcfet1 knockout mutants require plant-derived iron to achieve larger necrotic lesions, whereas in planta analyses of reactive oxygen species (ROS) revealed increased ROS levels only for infections caused by the bcfet1 mutant. These results suggest that increased ROS production, under an iron sufficiency environment, at least partly underlie the observed infection phenotype in this mutant. IMPORTANCE The plant-pathogenic fungus B. cinerea causes enormous economic losses, estimated at anywhere between $10 billion and $100 billion worldwide, under both pre- and postharvest conditions. Here, we present the characterization of a loss-of-function mutant in a component involved in iron acquisition that displays hypervirulence. While in different microbial systems iron uptake mechanisms appear to be critical to achieve full pathogenic potential, we found that the absence of the ferroxidase that is part of the reductive iron assimilation system leads to hypervirulence in this fungus. This is an unusual and rather underrepresented phenotype, which can be modulated by iron levels in the plant and provides an unexpected link between iron acquisition, reactive oxygen species (ROS) production, and pathogenesis in the Botrytis-plant interaction.

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“…(1983) showed that soilborne sclerotia of B. cinerea could survive in the field for up to 15 months. Work done by Hsiang & Chastagner (1992) indicated a longer period of survival, with B. cinerea sclerotia buried at 10 and 20 cm in field soil having an average viability of 77% after 18 months. However, Raposo et al.…”

Section: Discussionmentioning

confidence: 99%

Overwintering grapevine debris as an important source of Botrytis cinerea inoculum

et al. 2012

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Production of Botrytis cinerea conidia from infected grapevine debris (trash) left on the ground and in the canopy in the season following harvest was studied in vineyards in Marlborough, New Zealand. When subsamples were incubated under high relative humidity in the laboratory, rachides had the greatest sporulation potential (P < 0AE05), followed by tendrils, cane lengths and petioles. Trash remaining on the ground under the canopy had higher rates of sporulation (P < 0AE05) than that in the inter-row. The sporulation potential of rachides at different times during the growing season was assessed by placing them in vine canopies or on the inter-row soil in three vineyards in late spring. Subsamples were removed on five occasions between flowering (capfall) and harvest, and incubated under high relative humidity in the laboratory. Mean numbers of conidia produced from the canopy rachides diminished from 3AE5 · 10 5 per rachis at capfall to 2AE6 · 10 4 at harvest, and from 3AE9 · 10 5 to 2AE7 · 10 3 , respectively, from the ground rachides. The greater loss in sporulation capacity of ground rachides was considered to be associated with their earlier spontaneous sporulation and greater degradation in the moist inter-row sward, where they lost 29% of their weight (P < 0AE001) and 23% of their pedicels (P < 0AE001), compared to the canopy rachides which lost 0% of their weight and 3% of their pedicels from capfall to harvest. This study has shown that necrotic, overwintering grapevine debris can produce B. cinerea conidia throughout the following growing season, so may contribute to the subsequent risk of bunch rot.

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Production and viability of sclerotia from fungicide‐resistant and fungicide‐sensitive isolates of Botrytis cinerea, B. elliptica and B, tulipae

Cited by 24 publications

References 19 publications

Resistance to Dicarboximide Fungicides in a Canadian Population of Microdochium nivale

Resistance to Dicarboximide Fungicides in a Canadian Population of Microdochium nivale

Defects in the Ferroxidase That Participates in the Reductive Iron Assimilation System Results in Hypervirulence in Botrytis Cinerea

Overwintering grapevine debris as an important source of Botrytis cinerea inoculum

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