Detection of interactions between the pea root rot pathogens Aphanomyces euteiches and Fusarium spp. using a multiplex qPCR assay

2018 ◽  
Vol 67 (9) ◽  
pp. 1912-1923 ◽  
Author(s):  
T. L. Willsey ◽  
S. Chatterton ◽  
M. Heynen ◽  
A. Erickson
Author(s):  
D. J. Stamps

Abstract A description is provided for Aphanomyces euteiches. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Pea, Arabis, pansy, sweet pea, clover, bean, lupin, vetch, lucerne, Melilotus, barley, oats, Echinodorus brevipedicellatus. Conifer seedlings and other hosts were infected by inoculation. DISEASE: Root rot of pea. GEOGRAPHICAL DISTRIBUTION: Asia (Japan); Australia (Tasmania); Europe (UK, Denmark, France, Norway, Sweden, USSR); N. America (USA). (CMI Map 78, ed. 3, 1977). TRANSMISSION: Soil-borne, persisting in the soil for many years. Studies in Wisconsin suggested that A. euteiches may live as a weak parasite in the roots of many plants and occur naturally in some virgin soils (6, 523). Oospores were indicated to be the primary inocula for new outbreaks of pea root rot, zoospores the primary infective agents (39, 646). Survival between pea crops depended on oospore durability and possible alternative hosts, not saprophytic activity (41, 689). Studies were made of population dynamics in the soil (48, 2067) and penetration and infection of roots by zoospores (42, 287).


2014 ◽  
Vol 62 (20) ◽  
pp. 4584-4591 ◽  
Author(s):  
Shakhawat Hossain ◽  
Göran Bergkvist ◽  
Kerstin Berglund ◽  
Robert Glinwood ◽  
Patrick Kabouw ◽  
...  

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 529B-529
Author(s):  
M.A. Chandler ◽  
V.A. Fritz ◽  
F.L. Pfleger ◽  
R.R. Allmaras

Pea root rot is a serious economic threat to pea production in the Great Lakes region. The primary causal organism is Aphanomyces euteiches Drechs., which is responsible for an estimated 10% annual crop loss. A fall oat (Avena sativa) rotation before spring pea planting reduces disease severity. To better understand the beneficial effect of oat on A. euteiches, isolated individual pathogen lifecycle stages of zoospores, mycelium, and oospores were treated in culture with oat extract. Resulting mycelial mats were dried and weighed. Treatment with 90%, 70%, 50%, and 30% oat extract resulted in significant spore germination and mycelial growth of A. euteiches. In the presence of nutrient solution, oat extract concentrations of 90%, 70%, 50%, and 30% significantly enhanced spore germination and mycelial growth of the pathogen. These results demonstrate that the use of oat extract results in dosage dependent germination and growth of A. euteiches.


Plant Disease ◽  
1999 ◽  
Vol 83 (12) ◽  
pp. 1108-1112 ◽  
Author(s):  
L. Persson ◽  
M. Larsson-Wikström ◽  
B. Gerhardson

The ability of field soils to suppress pea root rot caused by Aphanomyces euteiches was assessed in field soil samples in a greenhouse bioassay and in field experiments sown with pea in monoculture for four years. In the bioassay, an inoculum of oospores in talcum powder was added to the test soils 1 week prior to sowing of pea seeds. The rate of infection was assessed 4 weeks after sowing. The field experiments were placed in six localities with varying degrees of soil suppressiveness to pea root rot and the pea yield and number of oospores of A. euteiches in root tissue were measured each year. A large variation in disease suppression was found in 24 arbitrarily chosen soils, sampled in the vining pea growing area in southern Sweden, and some soils were found to be strongly disease suppressive. The pea root rot development was also clearly different between the field experiments, depending on the soil. In an experiment on a soil showing low disease suppressiveness in the greenhouse bioassay, the crop failed in the second year, the number of oospores in root tissue increased rapidly over time, and no yield at all could be taken the fourth year. In contrast, on a soil with a high disease suppressiveness in the bioassay, the pea monoculture led to a slow build-up of oospores in root tissue and a steady high yield of 5,300 kg/ha the fourth year.


Plant Disease ◽  
2002 ◽  
Vol 86 (4) ◽  
pp. 411-414 ◽  
Author(s):  
R. D. Peters ◽  
C. R. Grau

Aphanomyces euteiches is an important root-rotting pathogen of pea. When recovering isolates of A. euteiches from infested soils in Wisconsin using pea as a bait host, isolates of Fusarium solani often were recovered. Experiments were established to compare disease symptoms of pea seedlings inoculated with isolates of A. euteiches and F. solani alone or in combination. Inoculation of pea seedlings with either of two isolates of A. euteiches produced typical root rot symptoms. However, inoculation of pea seedlings with an isolate of F. solani resulted in no disease symptoms, indicating that the isolate was nonpathogenic to pea. Co-inoculation of pea seedlings with A. euteiches and the nonpathogenic isolate of F. solani resulted in significantly (P = 0.05) greater disease severity than inoculation with A. euteiches alone. Both A. euteiches and F. solani could be reisolated, individually or together, from pea seedlings following individual or co-inoculations, respectively. Although the mechanisms of interaction between these two species are unknown, the synergism documented in this study indicates that the interactions of pathogens with nonpathogens may affect development of disease symptoms.


Plant Disease ◽  
2013 ◽  
Vol 97 (4) ◽  
pp. 461-471 ◽  
Author(s):  
F. Heyman ◽  
J. E. Blair ◽  
L. Persson ◽  
M. Wikström

A root rot disease of pea and faba bean caused by a Phytophthora sp. was observed in fields and field soil samples in southern Sweden. Observations of the disease in pea root rot greenhouse assays were systematically recorded, and incidence and geographic distribution data were compared with the pea root rot caused by Aphanomyces euteiches. Following one successful isolation of the pathogen, isolation procedures and selective media were optimized to retrieve more isolates. Phylogenetic analysis showed that the isolates belong to a novel lineage, closely related to Phytophthora sojae, and proposed here as a new species, P. pisi sp. nov. In a collection of 13 isolates from separate fields, intraspecific variation was detected in both nuclear and mitochondrial loci. Pathogenicity tests on a range of crop plants and wild legumes suggest that the host range of the pathogen is restricted to a group of legumes closely related to pea which, in addition to pea, include the crop species faba bean, lentil, common vetch, and chickpea. Morphology, growth requirements, and pathogenicity traits indicate that the species may be identical to the organism previously described as P. erythroseptica var. pisi. The work characterizes a novel Phytophthora sp. causing root rot of legume crops.


Author(s):  
M. Walter ◽  
C.M.A. Frampton ◽  
P.A.G. Elmer ◽  
R.A. Hill

2017 ◽  
Vol 63 (9) ◽  
pp. 758-768 ◽  
Author(s):  
A. Esmaeili Taheri ◽  
S. Chatterton ◽  
B.D. Gossen ◽  
D.L. McLaren

Oomycetes are a diverse group of microorganisms; however, little is known about their composition and biodiversity in agroecosystems. Illumina MiSeq was used to determine the type and abundance of oomycetes associated with pea root rot in the Canadian prairies. Additional objectives of the study were to identify differences in oomycete communities associated with pea root health and compare oomycete communities among the 3 prairie provinces, where field peas are commonly cultivated. Samples of soil from the rhizosphere of field pea (Pisum sativum L.) were collected from patches of asymptomatic or diseased plants from 26 commercial fields in 2013 and 2014. Oomycete communities were characterized using metagenomic analysis of the ITS1 region on Illumina MiSeq. From 105 identified operational taxonomic units (OTUs), 45 and 16 oomycete OTUs were identified at species and genus levels, respectively. Pythium was the most prevalent genus and Pythium heterothallicum the most prevalent species in all 3 provinces in both 2013 and 2014. Aphanomyces euteiches, a very important pea root rot pathogen in regions of the prairies, was detected in 57% of sites but at very low abundance (<0.2%). Multivariate analysis revealed differences in the relative abundance of species in oomycete communities between asymptomatic and diseased sites, and among years and provinces. This study demonstrated that deep amplicon sequencing can provide information on the composition and diversity of oomycete communities in agricultural soils.


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