The signal crayfish (Pacifastacus leniusculus) in Lake Tahoe (USA) hosts multiple Aphanomyces species

Abstract

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Preliminary survey of Aphanomyces sp. associated with native and invasive crayfish in the Lower Susquehanna watershed of South Central Pennsylvania

“…Phylogenetic comparison to other Aphanomyces suggests that these samples are unique and more closely related to the fish pathogen A. salsuginosus than to A. astaci (Figure 2). Sequences of the ITS locus were identical across all A. astaci samples collected here ( Figure 2), and were also identical to an A. astaci sequence obtained from signal crayfish in Lake Tahoe, CA (Makkonen et al 2019); a single SNP differed between our sequences and that of the L1 strain originally isolated from Astacus astacus (Figure 2).…”

“…While the resulting 'crayfish plague' pathogen has been extensively studied throughout Europe, very little is known about the ecology or prevalence of A. astaci within its presumed native range. Only two studies to date have isolated A. astaci from latently infected native crayfish species collected within North America (Makkonen et al 2019;Panteleit et al 2019).…”

Experimental evaluation of the potential for crayfish plague transmission through the digestive system of warm‐blooded predators

“…For example, strains of the genotype group D did not show better survival than strains from other genotype groups (Figure 3) although they seem to be favoured under less extreme temperatures from 27°C to 29.5°C (Diéguez-Uribeondo, Huang, Cerenius, & Söderhäll, 1995). However, we observed substantial differences in survival of the two tested strains of the genotype group D, suggesting that various physiological characteristics may vary even among closely related A. astaci strains that belong to the same genotype group (as has been already observed for virulence; e.g., Makkonen, Jussila, Kortet, Vainikka, & Kokko, 2012;Makkonen et al, 2019;Makkonen et al, 2014). Interestingly, A. astaci mycelium sometimes did not start to grow noticeably until the third week after the exposure to high temperatures, while the growth of A. astaci was apparent after 1 week in almost all controls and in most of the cultures that have survived the incubation at high temperatures.…”

Narrow-clawed crayfish in Finland: Aphanomyces astaci resistance and genetic relationship to other selected European and Asian populations

“…The experimental system consisted of individual interconnected 2 L tanks with recirculating filtered water from the lake Kallavesi, the detailed system design as described by Jussila et al (2011) and Makkonen et al (2019) at a flow rate that ensured full turnover of the 2 L tanks every hour. The system contamination by A. astaci was prevented by filtration using set up described by Jussila et al (2013).…”

“…We used PsI-Tahoe (UEF_T16B, B haplogroup) and PsI-Puujärvi (UEF8866-2, B haplogroup) isolates from signal crayfish (Makkonen et al, 2011(Makkonen et al, , 2012a(Makkonen et al, ,b, 2014 to infect the experimental crayfish. Both isolates have been reported to be very virulent (Jussila et al, 2013b;Makkonen et al, 2019) and thus a good candidate for A. astaci isolate virulence comparisons. Both of these isolates had been isolated by the University of Eastern Finland crayfish research group and then maintained on PG1-agar (Unestam, 1965).…”