<i>Phytophthora irrigata</i>, a new species isolated from irrigation reservoirs and rivers in Eastern United States of America

Hong, Chuanxue; Gallegly, M. E.; Richardson, Patricia A.; Kong, Ping; Moorman, Gary W.

doi:10.1111/j.1574-6968.2008.01226.x

Cited by 40 publications

(24 citation statements)

References 32 publications

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“…Several new species have recently been described from ITS Clade 9 from irrigation water (Hong et al 2008(Hong et al , 2010, however, the pathogenicity of these species is unknown and they may fill a similar ecological niche to that proposed for Clade 6 with a predominance in native riparian, forest and woody ecosystems (Brasier et al 2003a;Jung et al 2011;Nechwatal et al 2012). Davison et al (2005) had previously isolated P. cinnamomi var.…”

Section: Discussionmentioning

confidence: 99%

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Fishing for Phytophthora from Western Australia’s waterways: a distribution and diversity survey

Hüberli

Hardy

White

et al. 2013

Australasian Plant Pathol.

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During one spring season, 12 Phytophthora species, two Phytophthora hybrids, three Halophytophthora species and three Phytopythium species, were isolated from 48 waterways across Western Australia. The waterways were sampled using nylon mesh bags containing leaf baits of up to six different plant species and were isolated by plating necrotic lesions on these onto Phytophthora-selective agar media. Phytophthora species were isolated from all except one waterway. Of the Phytophthora species isolated, eight are known while the remaining four are undescribed taxa. Six of the Phytophthora species and the two hybrids are from clade 6. The two hybrids and P. inundata were the predominant species recovered.Recoveries from different plant leaf baits varied with the best two baits being Pittosporum undulatum and Banksia attentuata; and from these two combined all Phytophthora species were isolated. There was a marked difference in the Phytophthora diversity in the waterways from different regions. This is the first comprehensive study from Australia to examine the Phytophthora communities in waterways, and advances our understanding of the role of these oomycetes in natural and anthropized ecosystems.

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Section: Discussionmentioning

confidence: 99%

“…Brasier et al 2003a;Hong et al 2008;Hulvey et al 2010;Reeser et al 2011;Scibetta et al 2012). Among this list are the notorious plant pathogens, P. ramorum and P. cinnamomi (Palzer 1980;Von Broembsen 1984;Smith et al 2009;Sutton et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Fishing for Phytophthora from Western Australia’s waterways: a distribution and diversity survey

Hüberli

Hardy

White

et al. 2013

Australasian Plant Pathol.

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“…Phytophthora citricola, Phytophthora citrophthora, Phytophthora insolita, Phytophthora irrigata, Phytophthora megasperma, Phytophthora nicotianae, and Phytophthora tropicalis, were used in this study (Table 1). These species were selected because of their frequent recovery from recycling irrigation systems in the Mid-Atlantic region, including Virginia, Maryland, Pennsylvania, and North Carolina (9,10,20,21) and from natural waterways in Virginia (C. Hong, unpublished data). These species were also selected because of their potential economic significance (14, 16, 20, 24, 25; USDA fungal databases at http://nt.ars-grin.gov/fungaldatabases/).…”

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confidence: 99%

Zoosporic Tolerance to pH Stress and Its Implications for Phytophthora Species in Aquatic Ecosystems

Kong

Moorman

Lea‐Cox

et al. 2009

Appl Environ Microbiol

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Phytophthora species, a group of destructive plant pathogens, are commonly referred to as water molds, but little is known about their aquatic ecology. Here we show the effect of pH on zoospore survival of seven Phytophthora species commonly isolated from irrigation reservoirs and natural waterways and dissect zoospore survival strategy. Zoospores were incubated in a basal salt liquid medium at pH 3 to 11 for up to 7 days and then plated on a selective medium to determine their survival. The optimal pHs differed among Phytophthora species, with the optimal pH for P. citricola at pH 9, the optimal pH for P. tropicalis at pH 5, and the optimal pH for the five other species, P. citrophthora, P. insolita, P. irrigata, P. megasperma, and P. nicotianae, at pH 7. The greatest number of colonies was recovered from zoospores of all species plated immediately after being exposed to different levels of pH. At pH 5 to 11, the recovery rate decreased sharply (P < 0.0472) after 1-day exposure for five of the seven species. In contrast, no change occurred (P > 0.1125) in the recovery of any species even after a 7-day exposure at pH 3. Overall, P. megasperma and P. citricola survived longer at higher rates in a wider range of pHs than other species did. These results are generally applicable to field conditions as indicated by additional examination of P. citrophthora and P. megasperma in irrigation water at different levels of pH. These results challenge the notion that all Phytophthora species inhabit aquatic environments as water molds and have significant implications in the management of plant diseases resulting from waterborne microbial contamination.Phytophthora species, a group of oomycetes in the kingdom of Stramenopila and well-known plant pathogens, were first listed as "water molds" by Blackwell in 1944 (5), and this notion has since been generally accepted. These species are phylogenetically close to golden-brown algae, although morphologically and physiologically, they resemble fungi. Most algae are aquatic in nature. Phytophthora species produce flagellate zoospores as their primary dispersal structure (35)(36)(37)39). Zoospores can travel in aquatic environments actively on their own locomotion and passively through water movement (12,13,41).More than 20 species of Phytophthora, including P. ramorum, the sudden oak death pathogen, have been isolated from irrigation reservoirs and natural waterways (20-22, 30, 40, 43), and a number of previously unknown taxa also have been documented in aquatic environments (8,24). These pathogens pose a threat to agricultural sustainability and natural ecosystems, as agriculture increasingly depends on recycled water for irrigation in light of rapidly spreading global water scarcity (19,22). Recycling irrigation systems provide an efficient means of pathogen dissemination from a single point of infection to an entire farm and from a single farm to other farms sharing the same water resources (22,24).A search of science-based solutions to this crop health issue reveals a surprisi...

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“…A variety of plant pathogens including bacteria, fungi and oomycetes are present in the RIRs [23], among which Phytophthora species are the most economically important to nursery production. Phytophthora species, such as P. gonapodyides and P. pini have been reported to survive best at temperature 20-25 °C [9,24] and a few high-temperature tolerant species, such as P. aquimorbida, P. hydrogena, P. hydropathica, P. insolita, P. irrigata, and P. virginiana have an optimal growth temperature of 35 °C [4][5][6][7][8]. Temperature differences between these two sampling points of within 1 °C would not alter the temperature biome for pathogen activities.…”

Section: Discussionmentioning

confidence: 99%

“…Phosphorous becomes less available to the plants when pH is above 7.2 [3]. Water temperature (T) [4][5][6][7][8][9], pH [10], dissolved oxygen (DO) [11], EC [12] and oxidation-reduction potential (ORP) [13] also affect the survival and growth of plant pathogens in the same reservoirs.…”

Section: Introductionmentioning

confidence: 99%

Comparative Analysis of Water Quality between the Runoff Entrance and Middle of Recycling Irrigation Reservoirs

Zhang

Richardson

Belayneh

et al. 2015

Water

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Recycling irrigation reservoirs (RIRs) are an emerging aquatic ecosystem of critical importance, for conserving and protecting increasingly scarce water resources. Here, we compare water quality between runoff entrance and middle of four RIRs in nurseries in Virginia (VA) and Maryland (MD). Surface water temperature (T) and oxidation-reduction potential (ORP) were lower in the middle than at the entrance, while the trend was opposite for dissolved oxygen (DO), pH and chlorophyll a (Chla). The magnitude of these differences between the entrance and middle decreased with increasing depth. These differences were magnified by water stratification from April to October. Minimum differences were observed for electrical conductivity (EC), total dissolved solids (TDS) and turbidity (TUR). Cluster analyses were performed on water quality difference data to evaluate whether the differences vary with respect to reservoirs. Two clusters were OPEN ACCESSWater 2015, 7 3862 formed with one consisting primarily of VA reservoirs, and the other consisting mostly of MD reservoirs in both years. Water quality in the middle and at the entrance of RIRs was expected to vary greatly because of runoff inflow. The two-point water quality differences observed here, although statistically significant, are not large enough to cause significant impact on crop health and productivity for most water quality parameters except pH. Additional analysis of outlet data shows that the range and magnitude of water quality difference between the middle and the outlet are comparable to those between the middle and entrance of RIRs. These results indicate that monitoring at a single point is sufficient to obtain reliable water quality estimates for most water quality parameters in RIRs except pH. This is important when considering the cost of labor and equipment necessary for documenting water quality in agricultural production systems. However, additional pH measurements are still necessary to make practical water quality management decisions.

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Phytophthora irrigata, a new species isolated from irrigation reservoirs and rivers in Eastern United States of America

Cited by 40 publications

References 32 publications

Fishing for Phytophthora from Western Australia’s waterways: a distribution and diversity survey

Fishing for Phytophthora from Western Australia’s waterways: a distribution and diversity survey

Zoosporic Tolerance to pH Stress and Its Implications for Phytophthora Species in Aquatic Ecosystems

Comparative Analysis of Water Quality between the Runoff Entrance and Middle of Recycling Irrigation Reservoirs

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