Identification and characterization of Botrytis medusae, a novel cryptic species causing grey mould on wine grapes in Australia

Abstract

In a collection of 735 Botrytis isolates sampled from Australian wine grape‐growing regions, a single isolate from clade I and group I (based on Bc‐hch RFLP analysis) was found. As many Botrytis species are known to live sympatrically, it was hypothesized that this isolate might be a new Botrytis species. After phenotypic and molecular assays supported this hypothesis, the species was designated B. medusae. Phylogenetic analyses using the nuclear genes G3PDH, HSP60, RPB2, NEP1 and NEP2 consistently placed B. medusae in an early‐diverging clade I Botrytis spp. lineage. Botrytis medusae produced white aerial mycelium, grew faster at 30 °C and produced long‐branched conidiophore extensions, compared with B. cinerea and B. pseudocinerea. Botrytis medusae was only able to infect wounded grape leaves and was significantly less virulent on wounded leaves and berries than B. cinerea. Botrytis medusae also lacked villiform appendages on the conidial surface and long conidiophores, which are defining features of B. sinoviticola and B. californica, respectively. Identification and characterization of new cryptic Botrytis species living in sympatry on grapevines could potentially provide information to assist disease management strategies for B. cinerea.

Population Genetic Analyses of Botrytis cinerea Isolates From Michigan Vineyards Using a High-Throughput Marker System Approach

“…Thousands of studies across the globe have used morphological, genic, microsatellite, and other PCR-based markers to characterize genetic diversity and population structure of Botrytis spp. The pathogen is genetically diverse with closely related morphologically similar species that can be found on the same host or tissue complicate diversity studies (Walker et al, 2011;Li et al, 2012;Saito et al, 2016;Garfinkel et al, 2017;Rupp et al, 2017b;Hu et al, 2018;Harper et al, 2019). While it is widely accepted that population structure exists within Botrytis, the degree and factors by which populations can be differentiated has not been consistent.…”

“…Population structure and genetic variations have been studied in B. cinerea populations, and new morphologically identical or similar species were identified. Recently a number of cryptic species causing gray mold that lives in sympatry with the B. cinerea complex have been identified on a variety of hosts (Li et al, 2012;Saito et al, 2016;Dowling et al, 2017;Rupp et al, 2017b;Harper et al, 2019). These new cryptic species are more likely considered as host or region specific.…”

Fungicide resistance characterised across seven modes of action inBotrytis cinereaisolated from Australian vineyards

“…Induction of sporulation and the harvesting of conidia for all isolates was carried out as previously described by Harper et al (2019), with two modifications. YSS agar (YSSA) was used for culturing instead of PDA and the conidial suspension was adjusted to 10 5 conidia mL -1 , instead of 10 7 conidia mL -1 .…”

“…MDR1 candidate isolates Bc-128 and Bc-391 were genotyped for Mrr1 as they grew on the fludioxonil discriminatory concentration (DC) of 0.1 ug/mL and were subsequently designated flu MR (Figure 8, Table S4). DNA was extracted from isolates as previously described by Harper et al (2019). The primers used to amplify promoter and gene regions, and their respective annealing temperatures and extension times are shown in Table S5.…”

Characterization of Growth Morphology and Pathology, and Draft Genome Sequencing of Botrytis fabae, the Causal Organism of Chocolate Spot of Faba Bean (Vicia faba L.)

“…Two single spore isolates were produced from the two samples and these were designated SCD-16-611 and DLY-16-612, abbreviated in this paper as Bf 611 and Bf 612, respectively. B. cinerea isolate Bc7 was obtained from Dr. Francisco Lopez-Ruiz (Centre for Crop and Disease Management, Curtin University, Australia) for inclusion in growth morphology and pathology studies (Harper et al, 2019). B. fabae Bf 611, Bf 612 and B. cinerea Bc7 were maintained as agar plugs at 4 • C for routine use in the laboratory.…”