Phytophthoraspecies recovered from the Connecticut River Valley in Massachusetts, USA

Abstract

Little is currently known about the assemblage of Phytophthora species in northeastern North America, representing a gap in our understanding of species incidence. Therefore, Phytophthora species were surveyed at 20 sites in Massachusetts, with 16 occurring in the Connecticut River Valley. Many of the sampled waterways were adjacent to active agricultural lands, yet were buffered by mature floodplain forests composed of Acer, Platanus, Populus and Ulmus. Isolates were recovered with three types of baits (rhododendron leaves, pear, green pepper) in 2013 and water filtration in 2014. Overall, 457 isolates of Phytophthora were recovered and based on morphological characters and rDNA internal transcribed spacer (ITS), β-tubulin (β-tub) and cytochrome oxidase c subunit I (cox1) sequences, 18 taxa were identified, including three new species: P. taxon intercalaris, P. taxon caryae and P. taxon pocumtuck. In addition, 49 isolates representing five species of Phytopythium also were identified. Water filtration captured a greater number of taxa (18) compared to leaf and fruit baits (12). Of the three bait types rhododendron leaves yielded the greatest number of isolates and taxa, followed by pear and green pepper, respectively. Despite the proximity to agricultural lands, none of the Phytophthora species baited are considered serious pathogens of vegetable crops in the region. However, many of the recovered species are known woody plant pathogens, including four species in the P. citricola s.l. complex that were identified: P. plurivora, P. citricola III, P. pini and a putative novel species, referred to here as P. taxon caryae. An additional novel species, P. taxon pocumtuck, is a close relative of P. borealis based on cox1 sequences. The results illustrate a high level of Phytophthora species richness in the Connecticut River Valley and that major rivers can serve as a source of inoculum for pathogenic Phytophthora species in the northeast.

Phytophthora hydropathica y Phytophthora drechsleri aisladas de canales de irrigación del Valle de Culiacán

“…These studies show that P. hydropathica is a threat for tomato and chilli crops, which are extremely important in this region. Similar studies (Bienapfl and Balci, 2014;Brazee et al, 2016), mention that although P. hydropathica rarely has been found to have a relation to plant diseases, it does have the potential to cause diseases.…”

“…Examples of species reported with this dispersal mean include P. cactorum, P. parasitica, P. citricola, P. gonapodyides, and P. cambivora, isolated from irrigation waters in the state of Washington (Yamak et al, 2002). Recently, one of the species with the greatest incidence in surface waters has been P. hydropathica (Brazee et al, 2016;Ghimire et al, 2011;Hulvey et al, 2010). In most of these cases,…”

“…Algunos ejemplos de especies reportadas con este medio de diseminación son: P. cactorum, P. parasitica, P. citricola, P. gonapodyides y P. cambivora, aisladas de aguas de irrigación en el estado de Washington (Yamak et al, 2002). Recientemente una de las especies con mayor incidencia en aguas superficiales es la especie P. hydropathica (Brazee et al, 2016;Ghimire et al, 2011;Hulvey et al, 2010). En la mayoría de estos casos, la presencia de especies de Phytophthora en agua no se ha relacionado con la existencia de síntomas o daños en hospedantes vegetales terrestres (Resser et al, 2011).…”

“…In the channels where Phytophthora was found, P. hydropathical was found in only 40 %, in 30 % only P.drechsleri, and in 30 %, both species ( Figure 6). P. hydropathica is considered a native species to river ecosystems (Hong et al, 2010), therefore it is very common to find, in this type of studies, a high frequency of isolates of this species (Bienapfl and Balci, 2014;Brazee et al 2016).…”

“…P. hydropathica es considerada una especie nativa de ecosistemas fluviales (Hong et al, 2010) por lo que es muy común en este tipo de estudios encontrar una alta frecuencia de aislamientos de esta especie (Bienapfl y Balci, 2014;Brazee et al 2016).…”