scholarly journals Multi-Year Evaluation of Commercial Soybean Cultivars for Resistance to Phytophthora sojae

Plant Disease ◽  
2010 ◽  
Vol 94 (3) ◽  
pp. 368-371 ◽  
Author(s):  
T. L. Slaminko ◽  
C. R. Bowen ◽  
G. L. Hartman
Keyword(s):  
Resistance Genes ◽  
Root Rot ◽  
Rapid Development ◽  
Soybean Seed ◽  
Phytophthora Sojae ◽  
Primary Methods ◽  
Phytophthora Root Rot ◽  
Soybean Cultivars ◽  
Information Program ◽  
Poorly Drained Soils

Phytophthora sojae causes damping-off, root rot, and stem rot of soybean, particularly in poorly drained soils. Soybean cultivar resistance is one of the primary methods to control this disease, with Rps1c, Rps1k, and Rps1a being the most commonly used genes. The Varietal Information Program for Soybeans (VIPS) at the University of Illinois evaluates soybean cultivars for resistance to a number of diseases including Phytophthora root rot (PRR). The objectives of this research were to evaluate PRR resistance among commercial cultivars or advanced lines, and to compare these results with the information on PRR resistance provided by the company that entered the cultivar in VIPS. Each year from 2004 to 2008, between 600 and 900 cultivars were evaluated for resistance to either race 17 or 26 of P. sojae using the hypocotyl inoculation method. P. sojae single resistance genes were reported in 1,808 or 51% of the entries based on company information. Of these, the most commonly reported resistance genes were Rps1c (50%), Rps1k (40%), and Rps1a (10%). To a much smaller degree, companies reported using Rps3a (0.3%), Rps1b (0.2%), and Rps7 (0.2%). For the duration of the 5-year testing period, almost half of the cultivars (46%) were entered in VIPS with no reported resistance genes, and only nine out of a total of 3,533 entries (less than 0.3%) reported a stacked combination of resistance genes. Agreement between company-reported genes and any resistance found in the VIPS PRR evaluation was highest for those cultivars claiming to have Rps1c (90%) and Rps1k (83%), followed by Rps1a (70%). On average, 54% of the cultivars submitted to VIPS each year were new, reflecting the rapid development and turnover of soybean cultivars provided by the soybean seed companies.

Detached-petiole inoculation method to evaluate Phytophthora root rot resistance in soybean plants

2017 ◽  
Vol 68 (6) ◽  
pp. 555
Author(s):  
Yinping Li ◽  
Suli Sun ◽  
Chao Zhong ◽  
Zhendong Zhu
Keyword(s):  
Root Rot ◽  
Dominant Gene ◽  
Phytophthora Sojae ◽  
Single Dominant Gene ◽  
Phytophthora Root Rot ◽  
Inoculation Methods ◽  
Inoculation Technique ◽  
Soybean Cultivars ◽  
F2 Population ◽  
Soybean Resistance

Phytophthora root rot (PRR) caused by Phytophthora sojae, is one of the most destructive soybean diseases. The deployment of resistant cultivars is an important disease management strategy. To this aim, the development of a fast and effective method to evaluate soybean resistance to P. sojae is strategic. In this study, a detached-petiole inoculation technique was developed and its reliability was verified in soybean cultivars and segregant populations for PRR resistance. The detached-petiole and hypocotyl inoculation methods were used to assess the resistance of soybean cultivars, the F2 population of a Zhonghuang47 × Xiu94-11 cross, and the derived F2:3 population. The reactions of 13 analysed cultivars to three P. sojae isolates were consistent between the two inoculation techniques. The reactions of the F2 and F2:3 populations to isolate PsMC1 were 95.20% similar between the two inoculation methods. The segregation of the resistance and susceptibility fit a 3 : 1 ratio. Our results suggest that the detached-petiole technique is a reliable method, and reveal that the PRR resistance in Xiu94-11 is controlled by a single dominant gene. The phenotypic ratios of the tested Jikedou2 × Qichadou1 F2 population using the detached-petiole inoculation technique fit a 3 : 1 ratio (Resistance : Susceptibility). This demonstrated that Qichadou1 contains a single dominant gene conferring resistance to P. sojae. Our new detached-petiole inoculation technique is effective, reliable, non-destructive to the plant, and does not require an excessive amount of seeds. It may be suitable for the largescale screening of soybean resistance to multiple P. sojae isolates.

scholarly journals Adaptation of Phytophthora sojae to Rps Resistance Genes over the Past Two Decades in North Dakota

2019 ◽  
Vol 20 (2) ◽  
pp. 88-93 ◽  
Author(s):  
Hui Yan ◽  
Berlin Nelson
Keyword(s):  
North Dakota ◽  
Resistance Genes ◽  
Root Rot ◽  
Phytophthora Sojae ◽  
Red River ◽  
Phytophthora Root Rot ◽  
Red River Valley ◽  
The Past ◽  
Primary Management ◽  
New Strategies

Phytophthora root rot, caused by Phytophthora sojae, is a major disease of soybean in North Dakota, especially in the Red River Valley (RRV). Planting resistant cultivars is the primary management. The resistance genes Rps 1c, 1k, 3a, and 6 are the most common genes deployed in this region. To determine the efficacy of these genes and document the pathotype changes in the population of P. sojae over several decades, a survey of pathotypes was conducted in 2015 in three counties in the southern RRV and compared with similar surveys conducted in 1991 to 1994 and 2002 to 2004 in the same area. The results showed that from 1991 to 1994 when 6% of the pathotypes could defeat the Rps1c gene, by 2004 it was 57% of the pathotypes, and that percentage remained the same in 2015. However, in 1994 no pathotype could defeat Rps 1k, but by 2004 it was 12% and in 2015 it was 41%. Pathotypes that defeat Rps 3a and 6 have been few over the years. Pathotypes that defeat both 1c and 1k increased from none to 31% between 1994 and 2015. With the increasing complexity of P. sojae pathotypes, new strategies for managing this pathogen in the future will be needed.

scholarly journals Development of a Simple Hydroponic Assay to Study Vertical and Horizontal Resistance of Soybean and Pathotypes of Phytophthora sojae

Plant Disease ◽  
2018 ◽  
Vol 102 (1) ◽  
pp. 114-123 ◽  
Author(s):  
A. Lebreton ◽  
C. Labbé ◽  
M. De Ronne ◽  
A. G. Xue ◽  
G. Marchand ◽  
...  
Keyword(s):  
Virulence Factors ◽  
Root Rot ◽  
Dry Weight ◽  
Phytophthora Sojae ◽  
Horizontal Resistance ◽  
Phytophthora Root Rot ◽  
Hydroponic System ◽  
Long Term Stability ◽  
Vertical Resistance

Phytophthora root rot, caused by Phytophthora sojae, is one of the most damaging diseases of soybean and the introgression of Rps (Resistance to P. sojae) genes into elite soybean lines is arguably the best way to manage this disease. Current bioassays to phenotype the gene-for-gene relationship are hampered with respect to reproducibility and long-term stability of isolates, and do not accurately predict horizontal resistance individually. The aim of our study was to investigate a new way of phenotyping P. sojae isolates and vertical and horizontal resistance in soybean that relies on zoospores inoculated directly into a hydroponic system. Inoculation of P. sojae isolates against a set of eight differentials accurately and reproducibly identified pathotypes over a period of two years. When applied to test vertical resistance of soybean lines with known and unknown Rps genes, the bioassay relied on plant dry weight to correctly identify all genes. In addition, simultaneous inoculations of three P. sojae isolates, collectively carrying eight major virulence factors against 64 soybean lines with known and unknown levels of horizontal resistance, separated the plants into five distinct groups of root rot, allowing the discrimination of lines with various degrees of partial resistance. Based on those results, this bioassay offers several advantages in facilitating efforts in breeding soybean for P. sojae resistance and in identifying virulence factors in P. sojae.

Pyramided QTL underlying tolerance to Phytophthora root rot in mega-environments from soybean cultivars ‘Conrad’ and ‘Hefeng 25’

2010 ◽  
Vol 121 (4) ◽  
pp. 651-658 ◽  
Author(s):  
Xiuping Li ◽  
Yingpeng Han ◽  
Weili Teng ◽  
Shuzheng Zhang ◽  
Kangfu Yu ◽  
...  
Keyword(s):  
Root Rot ◽  
Phytophthora Root Rot ◽  
Soybean Cultivars

Races of Phytophthora sojae on Soybean in Illinois

2000 ◽  
Vol 1 (1) ◽  
pp. 32
Author(s):  
R. A. Leitz ◽  
G. L. Hartman ◽  
W. L. Pedersen ◽  
C. D. Nickell
Keyword(s):  
United States ◽  
Glycine Max ◽  
Root Rot ◽  
The United States ◽  
Phytophthora Sojae ◽  
Phytophthora Root Rot ◽  
Glycine Max L

Phytophthora root rot of soybean (Glycine max (L.) Merr.), caused by Phytophthora sojae M. J. Kauffmann & J. W. Gerdemann, has been isolated throughout the soybean-producing regions of the United States. Posted 3 June 2000.

scholarly journals Development and Application of qPCR and RPA Genus- and Species-Specific Detection of Phytophthora sojae and P. sansomeana Root Rot Pathogens of Soybean

Plant Disease ◽  
2017 ◽  
Vol 101 (7) ◽  
pp. 1171-1181 ◽  
Author(s):  
J. Alejandro Rojas ◽  
Timothy D. Miles ◽  
Michael D. Coffey ◽  
Frank N. Martin ◽  
Martin I. Chilvers
Keyword(s):  
Mitochondrial Genome ◽  
Internal Control ◽  
Root Rot ◽  
Phytophthora Sojae ◽  
Diagnostic Tools ◽  
Specific Detection ◽  
Phytophthora Root Rot ◽  
Phytophthora Spp ◽  
Field Season ◽  
Species Specific

Phytophthora root rot of soybean, caused by Phytophthora sojae, is one of the most important diseases in the Midwestern United States, and is estimated to cause losses of up to 1.2 million metric tons per year. Disease may also be caused by P. sansomeana; however, the prevalence and damage caused by this species is not well known, partly due to limitations of current diagnostic tools. Efficient, accurate, and sensitive detection of pathogens is crucial for management. Thus, multiplex qPCR and isothermal RPA (recombinase polymerase amplification) assays were developed using a hierarchical approach to detect these Phytophthora spp. The assays consist of a genus-specific probe and two species-specific probes that target the atp9-nad9 region of the mitochondrial genome that is highly specific for the genus Phytophthora. The qPCR approach multiplexes the three probes and a plant internal control. The RPA assays run each probe independently with a plant internal control multiplexed in one amplification, obtaining a result in as little as 20 mins. The multicopy mitochondrial genome provides sensitivity with sufficient variability to discern among different Phytophthora spp. The assays were highly specific when tested against a panel of 100 Phytophthora taxa and range of Pythium spp. The consistent detection level of the assay was 100 fg for the qPCR assay and 10 pg for the RPA assay. The assays were validated on symptomatic plants collected from Michigan (U.S.) and Ontario (Canada) during the 2013 field season, showing correlation with isolation. In 2014, the assays were validated with samples from nine soybean producing states in the U.S. The assays are valuable diagnostic tools for detection of Phytophthora spp. affecting soybean.

scholarly journals Identification of Resistance Genes to Phytophthora sojae in Domestic Soybean Cultivars from China Using Particle Bombardment

Plant Disease ◽  
2020 ◽  
Vol 104 (7) ◽  
pp. 1888-1893
Author(s):  
Jin Yang ◽  
Sujiao Zheng ◽  
Xiaomen Wang ◽  
Wenwu Ye ◽  
Xiaobo Zheng ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Particle Bombardment ◽  
Phytophthora Sojae ◽  
Stem Rot ◽  
Avirulence Genes ◽  
Breeding Programs ◽  
Soybean Cultivars ◽  
Primary Means ◽  
Soybean Plants ◽  
Source Materials

Phytophthora root and stem rot caused by Phytophthora sojae is a destructive disease that afflicts soybean plants throughout the world. The use of resistant soybean cultivars is the primary means of managing this disease, as well as the most effective and economical approach. There are abundant soybean germplasm resources in China that could be deployed for breeding programs; however, the resistance genes (Rps genes) in most cultivars are unknown, leading to uncertainty concerning which are resistant cultivars for use. The resistance genes Rps1a, Rps1c, and Rps1k prevent root and stem rot caused by most P. sojae isolates within a Chinese field population. This study identified three Rps genes in Chinese domestic soybean cultivars using three related avirulence genes by particle bombardment. The complex genetic diversity of soybean cultivars and P. sojae strains has made it difficult to define single Rps genes without molecular involvement. Gene cobombardment is a method for identifying Rps genes quickly and specifically. We showed that cultivars Dongnong 60 and Henong 72 contained Rps1a, while Hedou 19, Henong 76, 75-3, Wandou 21020, Zheng 196, Wandou 28, Heinong 71, and Wandou 29 all contained Rps1c. The cultivars Jidou 12, Henong 72, Heinong 71, and Wandou 29 contained Rps1k. The cultivar Henong 72 contained both Rps1a and Rps1k, while Wandou 29 and Heinong 71 contained both Rps1c and Rps1k. We then evaluated the phenotype of 11 domestic soybean cultivars reacting to P. sojae using the isolates P6497 and Ps1. The 11 domestic cultivars were all resistant to P6497 and Ps1. This research provides source materials and parent plant strains containing Rps1a, Rps1c, and Rps1k for soybean breeding programs.

Isolation, Storage, Pathotype Characterization, and Evaluation of Resistance for Phytophthora sojae in Soybean

2008 ◽  
Vol 9 (1) ◽  
pp. 35 ◽  
Author(s):  
Anne E. Dorrance ◽  
Sue Ann Berry ◽  
Terry R. Anderson ◽  
Chuck Meharg
Keyword(s):  
Resistance Genes ◽  
Partial Resistance ◽  
Genetic Resistance ◽  
Phytophthora Sojae ◽  
Soybean Cultivars

Phytophthora sojae is effectively managed through soybean cultivars with single resistance genes (Rps) and partial resistance inherited quantitatively. There are over 50 described races of Phytophthora sojae, but many more pathotypes have been reported. Many of the isolates recently collected are more complex, causing disease on plants with 3 or more Rps genes. This diagnostic guide provides some standard assays to assist in the identification of virulence types of P. sojae and genetic resistance in soybean. Accepted for publication 4 October 2007. Published 18 January 2008.

Comparison of Phytophthora sojae populations in Iowa and Nebraska to identify effective Rps genes for Phytophthora stem and root rot management

2021 ◽  
Author(s):  
Rashelle Matthiesen-Anderson ◽  
Clarice Schmidt ◽  
Vinicius C. Garnica ◽  
Loren Giesler ◽  
Alison E Robertson
Keyword(s):  
Root Rot ◽  
Partial Resistance ◽  
Specific Resistance ◽  
Phytophthora Sojae ◽  
Soybean Variety ◽  
Soybean Cultivars ◽  
Soybean Genotypes ◽  
Rps Gene ◽  
High Level ◽  
Almost All

Phytophthora stem and root rot (PSRR) of soybean, caused by the oomycete Phytophthora sojae, is prevalent in Iowa and Nebraska. Reducing losses to PSRR primarily relies on growing cultivars with specific resistance (Rps) genes. Predominant genes used in commercial soybean cultivars include Rps 1a, Rps 1c, Rps 1k, and Rps 3a. Knowing which Rps gene to deploy depends on knowledge of which genes are effective against the pathogen. From 2016 to 2018, 326 isolates of P. sojae from were recovered from fields in Iowa and Nebraska and classified into pathotypes based on their virulence on 15 soybean genotypes. A total of 15 and 10 pathotypes were identified in Iowa and Nebraska, respectively. Almost all isolates were virulent on Rps 1a, while over 70% of isolates were virulent on Rps 1c and Rps 1k. Only 2.3% of isolates from Iowa were virulent on Rps 3a. Among commercial soybean cultivars tested in the Illinois Soybean Variety trials from 2010 to 2020, Rps 1c was always the most frequently reported gene followed by Rps 1k. In contrast, Rps 1a and Rps 3a were present in less than 10% and less than 5 % of the cultivars tested, respectively. Since many of the P. sojae isolates in our study were virulent on Rps 1a, Rps 1c, and Rps 1k, soybean cultivars with these genes are unlikely to provide protection against PSRR unless they have a high level of partial resistance.

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