Temperature and Water Stress Effects on Sporangium Viability and Zoospore Discharge in Phytophthora cryptogea and P. megasperma

MacDonald, J. D.

doi:10.1094/phyto-68-1449

Cited by 21 publications

(6 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At high temperatures (30 "C) non-chilled cultures caused failure of zoospore release compared to chilled cultures. Zoospore discharge has been reported to occur at 30 "C but stops abruptly at 33 "C (MacDonald & Duniway, 1978). The optimum temperature for mycelial growth of P. cryptogea isolate BR7 was in the range 20 -25 "C similar to that reported by Brooks (1953) and Weste (1983).…”

Section: Discussionsupporting

confidence: 80%

Phytophthora cryptogea root rot of tomato in rock woo] nutrient culture. II. Effect of root zone temperature on infection, sporulation and symptom development

Kennedy

Pegg

1990

Annals of Applied Biology

View full text Add to dashboard Cite

The effect of root-zone temperature on Phytophthora cryptogea root rot was studied in tomato cv. Counter grown under winter and summer conditions in rockwool culture. A nutrient temperature of 25 "C resulted in increased root initiation and growth, higher in winter-grown than in summer-grown plants. Rhizosphere zoospore populations were greatly reduced at 25 "C and above.Growth of P. cryptogea in vitro was optimal between 20 "C and 25 "C and completely suppressed at 30 "C. Encystment was enhanced by increased temperatures above 20 "C. Zoospore release in vitro occurred in cultures maintained at constant temperatures in the absence of the normal chilling stimulus. Optimal release was at 10 "C; no zoospores were released at 30 "C.Inoculated, winter-grown tomato plants maintained at 15 "C developed acute aerial symptoms and died after 21 days. Comparable plants grown at a root-zone temperature of 25°C remained symptomless for the 3-months duration of the experiment. Summer-grown infected plants at the higher root temperature wilted but did not die. Enhanced temperature was ineffective as a curative treatment in summer-grown plants with established infection.Aerial symptoms of Phytophthora infection are seen as a function of the net amount of available healthy root. With high root zone temperatures this is determined by new root production and decreased inoculum and infection.

show abstract

Section: Discussionsupporting

confidence: 80%

Phytophthora cryptogea root rot of tomato in rock woo] nutrient culture. II. Effect of root zone temperature on infection, sporulation and symptom development

Kennedy

Pegg

1990

Annals of Applied Biology

View full text Add to dashboard Cite

show abstract

“…Plants sampled in the spring and fall months, when air and water temperatures typically are moderate, were more likely to be infested (15 of 22 infested plants = 68%) than plants sampled in the summer and winter months, when temperatures typically are more extreme. This seasonal pattern in plant root infestation was not unexpected, given that survival of some species of Phytophthora are negatively affected by temperatures below 13°C and above 30°C, and most species can actively grow and sporulate between 15 and 25°C (Erwin and Ribeiro, 1996;MacDonald and Duniway, 1978). However, no obvious seasonal patterns of infestation of individual plant species were observed, with infested plants of each wetland species found in different months in several seasons.…”

Section: Discussionmentioning

confidence: 88%

Phytophthora Species Associated with Plants in Constructed Wetlands and Vegetated Channels at a Commercial Plant Nursery Over Time

Ridge

Bell

Gitto

et al. 2019

hortte

View full text Add to dashboard Cite

Constructed wetlands have been used for decades in agricultural settings to remediate nutrients and other agrichemicals from irrigation runoff and drainage; however, little is known about the presence and distribution of Phytophthora species within irrigation runoff water being treated in constructed wetlands. Therefore, we collected plant samples from within vegetated runoff collection channels and treatment stages of two constructed wetland systems receiving irrigation runoff at a commercial plant nursery in Cairo, GA, to determine if roots of wetland plants were infested by species of Phytophthora. Samples were collected 12 times, at 1- to 2-month intervals, over a 19-month period, from Mar. 2011 through Sept. 2012. The sample period covered all four seasons of the year, so we could determine if the association of Phytophthora species with roots of specific plant species varied with season. Approximately 340 samples from 14 wetland plant species were collected, and 22 isolates of Phytophthora species were recovered. Phytophthora species were typically isolated from plants in channels receiving runoff water directly from plant production areas; Phytophthora species were not detected on plants where water leaves the nursery. No seasonal patterns were observed in plant infestation or presence of species of Phytophthora. In fact, Phytophthora species were rarely found to be associated with the roots of the wetland plants collected; species of Phytophthora were found infesting roots of only 6.5% of the 336 plants sampled. Species of Phytophthora were not found to be associated with the roots of golden canna (Canna flaccida), lamp rush (Juncus effusus var. solutus), duckweed (Lemna valdiviana), or sedges (Carex sp.) during the study period. The exotic invasive plant species marsh dayflower [Murdannia keisak (33% of samples infested)] and alligatorweed [Alternanthera philoxeroides (15% of samples infested)] were found to have the first and third highest, respectively, incidences of infestation, with smooth beggartick (Bidens laevis) having the second highest incidence of samples infested (22%). Management of invasive species in drainage canals and constructed wetland systems may be critical because of their potential propensity toward infestation by Phytophthora species. Plant species recommended for further investigation for use in constructed wetlands to remediate irrigation runoff include golden canna, marsh pennywort (Hydrocotyle umbellata), pickerelweed (Pontederia cordata), and broadleaf cattail (Typha latifolia). The results from this study provide an important first look at the associations between species of Phytophthora and wetland plants in constructed wetland systems treating irrigation runoff and will serve to further optimize the design of constructed wetlands and other vegetation-based treatment technologies for the removal of plant pathogens from irrigation runoff.

show abstract

“…The decline in ability to infect leaf baits was only observed during the first summer trial, when the average temperature of container solutions was 28°C during the day and 25°C at night, with extended periods of solution temperatures above 30°C. Previously, MacDonald and Duniway (16) reported that prolonged exposure to temperatures ≥30°C resulted in a consistent decline in the ability of sporangia of P. cryptogea to discharge zoospores. The optimum temperature for growth for P. cryptogea is 20 to 25°C, with the upper limits for zoospore release being 33°C (6,16).…”

Section: Perimeter Colonized (%) Ymentioning

confidence: 92%

“…Previously, MacDonald and Duniway (16) reported that prolonged exposure to temperatures ≥30°C resulted in a consistent decline in the ability of sporangia of P. cryptogea to discharge zoospores. The optimum temperature for growth for P. cryptogea is 20 to 25°C, with the upper limits for zoospore release being 33°C (6,16). Consequently, excessive daytime solution temperatures during the first summer trial may have adversely affected zoospore release by P. cryptogea.…”

Section: Perimeter Colonized (%) Ymentioning

confidence: 92%

In Situ Production of Zoospores by Five Species of Phytophthora in Aqueous Environments for Use as Inocula

Ridge¹,

Jeffers²,

Bridges³

et al. 2014

Plant Disease

View full text Add to dashboard Cite

The goal of this study was to develop a procedure that could be used to evaluate the potential susceptibility of aquatic plants used in constructed wetlands to species of Phytophthora commonly found in nurseries. V8 agar plugs from actively growing cultures of three or four isolates of Phytophthora cinnamomi, P. citrophthora, P. cryptogea, P. nicotianae, and P. palmivora were used to produce inocula. In a laboratory experiment, plugs were placed in plastic cups and covered with 1.5% nonsterile soil extract solution (SES) for 29 days, and zoospore presence and activity in the solution were monitored at 2- or 3-day intervals with a rhododendron leaf disk baiting bioassay. In a greenhouse experiment, plugs of each species of Phytophthora were placed in plastic pots and covered with either SES or Milli-Q water for 13 days during both summer and winter months, and zoospore presence in the solutions were monitored at 3-day intervals with the baiting bioassay and by filtration. Zoospores were present in solutions throughout the 29-day and 13-day experimental periods but consistency of zoospore release varied by species. In the laboratory experiment, colonization of leaf baits decreased over time for some species and often varied among isolates within a species. In the greenhouse experiment, bait colonization decreased over time in both summer and winter, varied among species of Phytophthora in the winter, and was better in Milli-Q water. Zoospore densities in solutions were greater in the summer than in the winter. Decreased zoospore activities for some species of Phytophthora were associated with prolonged temperatures below 13 or above 30°C in the greenhouse. Zoospores from plugs were released consistently in aqueous solutions for at least 13 days. This procedure can be used to provide in situ inocula for the five species of Phytophthora used in this study so that aquatic plant species can be evaluated for potential susceptibility.

show abstract

Temperature and Water Stress Effects on Sporangium Viability and Zoospore Discharge in Phytophthora cryptogea and P. megasperma

Cited by 21 publications

References 0 publications

Phytophthora cryptogea root rot of tomato in rock woo] nutrient culture. II. Effect of root zone temperature on infection, sporulation and symptom development

Phytophthora cryptogea root rot of tomato in rock woo] nutrient culture. II. Effect of root zone temperature on infection, sporulation and symptom development

Phytophthora Species Associated with Plants in Constructed Wetlands and Vegetated Channels at a Commercial Plant Nursery Over Time

In Situ Production of Zoospores by Five Species of Phytophthora in Aqueous Environments for Use as Inocula

Contact Info

Product

Resources

About