Summary of the 15th Annual Sudden Death Syndrome (SDS) Fall Meeting

 

Questions? Please contact Dean Malvick or Linda Kull

The 2012 SDS Fall Meeting will be hosted by Kansas State University. Please contact Doug Jardine at jardine@ksu.edu for more information.

The 15th annual Sudden Death Syndrome (SDS) Fall Meeting was held November 17-18 in St. Paul, MN.

The NCSRP sponsored the meeting, together with the United Soybean Board, the Minnesota Soybean Research and Promotion Council, the Minnesota Corn Growers Association, and three commercial seed companies (Monsanto, Pioneer, and Syngenta).

About eighty researchers, four soybean growers and four soybean checkoff staff attended the meeting.

View the 2011 powerpoint presentations, the summary of breakout sessions and the agenda below.

2011 Presentations
Click on the presentation title to view the powerpoint presentation

SDS Status and State Reports for 2011 (Dean Malvick, University of Minnesota).

2010 and 2011 was a tale of contrasts for SDS. In 2010, SDS was widespread and severe in many parts of the region, while 2011 was too hot and dry in most areas for the disease to develop. When it did, symptoms appeared late and did not substantially impact yield. An exception was areas in Michigan,, where weather conditions were more conducive to SDS and the number of counties where SDS is confirmed continued to climb.

Of the 14,845 F. virguliforme genes more than 500 were induced very strongly in the infected soybean roots.

The SDS pathogen – What have we learned? (Madan Bhattacharyya,C. R. Bowen, J. Haudenshield, G. Hartman, Binod B. Sahu, Nilwala Abeysekara , Ramesh Pudake, Catherine Brooke, Jordan Lillian Baumbach)

Candidate pathogenicity genes have been identified this year, some of which show high identity to known pathogenicity genes.The list of candidate pathogenicity genes suggest that multiple approaches are taken by the pathogen to cause SDS, and that the process is highly complex.

A routine transformation and homologous recombination system was developed for knocking out the selected candidate pathogenicity genes in F. virguliforme. The next step is to use this information in creating SDS resistant soybean lines.

Increasing success with SDS field trials (Roger Bowen, University of Illinois, USDA-ARS, and Jason Bond, Southern Illinois University)

We worked this year on improving field techiniques to compare soybean genotypesor treatments. The current challenges to SDS field research are (1) the variation introduced by topography, soil texture, crop history, and soil compaction (2) the large environmental influences on disease occurance, especially late summer precipitation, and (3) temperature, SCN interaction, genetics, and other epidemiological factors such as infection timing, symptom development, and toxin transport.

Microscopic observations were made of SCN-infected plants growing in SDS-infested soil to determine if SCN infection affects the amount and distribution of F. virguliforme in roots.

How soil organisms may impact SDS (Ahmad Fakhoury, Dean Malvick, Nenad Tatalovic, Greg Tylka, Leonor Leandro)

In the samples processed so far, differences in soil biota profiles seem to be a major determinant for the development of SDS hot spots in a field. We used three different, complementary approaches. Metagenomic analysis using sequencing proved to be particularly valuable in revealing differences in the composition of the biota in SDS hot spots compared to those from spots with low SDS incidence.

Based on a survey of about 65 plants from different fields in Minnesota in 2010 with confirmed SDS, 17% also were infected with BSR, suggesting that BSR may be interacting with SDS frequently. In Iowa, the mechanism behind SDS – SCN interactions is being studied by comparing the root infection process by both pathogens in the same plant.

The 2011 SDS Regional Variety Trial was one of the largest trials ever conducted in the region.

Genetics and Breeding Update (Brian Diers, Tim Pruski, Osman Radwan, Steve Clough, Dechun Wang, and Cathy Schmidt)

The effect of resistance QTL (quantitative trait loci, genes) in different backgrounds was tested this year to determine their usefulness in applied breeding programs. Low disease pressure led to variable results.

The VIGS (Virus Induced Gene Silencing) system was used successfully to determine if the loss of a gene leads to a different response to the toxin. Differentially expressed genes from resistant genotypes are promising candidate genes for soybean leaf resistance to the Fusarium virguliforme toxin. The constructs are being tested for other soybean diseases.

In Michigan, a total of 243 F4:5 lines that are segregating for SDS resistance derived from a new resistance source, GD2422, were evaluated for SDS resistance in the field. Entries in the 2011 SDS Regional Test have been genotyped with 5,361 SNP markers.

With 140 entries, the 2011 Regional SDS Variety Test was one of the largest ever conducted. Although disease pressure was low, several new MG1 lines with good resistance were identified. Most locations of the MGII and MGIV tests had acceptable disease pressure to allow for selection. Disease pressure was low in most MGIII tests, but good for eliminating more susceptible lines.

SDS Patents (Anne Hall, University of Minnesota)

Glyphosate and SDS ( X.B. Yang, Iowa State University)

SDS Management Options (Daren Mueller, Iowa State University)

SDS is difficult to manage. Scout fields to determine where the disease occurs and take note of the areas. Avoid planting susceptible varieties. Several genes for resistance have been identified, although resistance is not complete. Cultivars with resistance to SCN are usually less susceptible to SDS. Cultivar reactions can vary among location and year – therefore plant multiple cultivars on farm-wide basis and keep good notes.

Ridge-tilled soil warms earlier in the spring and increases drainage. In one study, many fields with SDS were found in eastern Iowa, but little or no SDS was found in ridge-tilled fields in that region. But note that tillage can also help to spread inoculum in field and between fields if equipment not cleaned.

Current seed treatment products are not effective against SDS. There may be some promising ones in the pipeline.

Electron micrograph of plant root infection by Fusarium virguliforme. Photo credit: S. Mansouri Click on image to view a larger version.

Application of New Genetic and Genomic Resources to the Improved Control of Soybean Sudden Death Syndrome (Silvia Cianzio, Madan Bhattacharyya, ISU; Ahmad Fakhoury, Jason Bond, Khalid Meksem, SIU; John Rupe, Pengyin Chen, Burt Bluhm, UA)

Research continues to utilize new genetic resources to manage SDS. Resistance genes are being identified, and we are releasing SDS resistant, high-yielding germplasm lines. Nine resistance genes (quantitative trait loci—QTL) have been identified. For the SDS pathogen, we are examining the genetic mechanisms of disease infection and symptom expression. Advances are being made in screening methods for identifying plant resistance.

 

 

2011 Breakout Sessions

The 2011 Workshop agenda included three Breakout Sessions with the goal to outline future SDS research needs. The outcomes are listed below.

SDS disease pressure in 2011 was generally low, but adequate to for selection.

Breakout Session #1—Soybean Plant Host Research Needs

• Continue to evaluate the soybean germplasm collection for SDS resistance. Including early and later Maturity Group germplasm lines and association mapping.
• Map QTLs (QTLs generally can be defined as “genes”) for SDS resistance.
• Validate QTLs (genes) for SDS resistance.
• Identify genes responsible for SDS foliar and root resistance.
• Improve phenotyping methods (phenotyping refers to what an organism looks like as a result of genes and the environment).
• Clarify the interaction of SDS with other diseases.

Three approaches were used to assess biodiversity in soil samples, and to predict SDS hotspots. Click on image to view a larger version.

Breakout Session #2—Pathogen (Fusarium virguliforme) Research Needs

• Continue studies to understand the mode of action of the SDS toxin(s).
• Validate the QPCR methods among laboratories. Increase the exchange of information among laboratories and share SDS pathogen isolates.
• Continue to define the SDS pathogen variability with a focus on regions, environments, plot inoculations and evaluations.
• Continue studies to understand how the rhizosphere microbial populations impact the SDS pathogen and/or SDS foliar symptoms.
• Continue studies to understand to what extent the SDS pathogen varies in different regions and environments.
• Continue studies on the geographic distribution of the SDS pathogen and its impact on soybean symptoms.
• Focus also on areas with few SDS reports.

SDS Distribution and Impact 2006-2008 Click on image to view a larger version.

Breakout Session #3—Outreach and Educational Needs

• Develop a coordinating committee to update the SDS information on the Plant Health Initiative (PHI) Website.
• Link state SDS variety field test results and variety evaluations on the PHI website.
• Add information on the effects of irrigation on the SDS disease and efficacy of seed treatments
• Update the current SDS publications on the PHI website.
• Bring in publications and resources produced by other groups in the states dealing with SDS.
• Develop additional resources including pod casts, SDS publications, videos, and YouTube videos to communicate new information and management recommendations to soybean growers and others needing SDS information.
• Focus the website information to diverse target audiences including farmers, Certified Crop Advisors, educators, investigators, commodity industries, government agencies, and stakeholders in areas where SDS is beginning to show up.

 

2011 Agenda

(Click here for agenda in pdf format)

Thursday, November 17

12 Noon	Lunch
12:30 PM	Welcome, Introductions and Overview – USB Director and NCSRP (David Wright)
12:45	SDS Status and State Reports (led by Dean Malvick, University of Minnesota)
1:15	The SDS pathogen - what have we learned? Suggestions: variability and aggressiveness, biotech studies, detection, sequence analysis studies; toxin studies. (led by Madan Bhattacharyya, Iowa State University)
2:00	Increasing success with field trials (led by Jason Bond, Southern Illinois University and Roger Bowen, University of Illinois/USDA-ARS)
2:30	Afternoon Break
2:45	How soil organisms may impact SDS (led by Ahmad Fakhoury, Southern Illinois University)
3:15	Genetics update (led by Brian Diers, University of Illinois)
4:00	SIU SDS patent discussion (led by UM Technology representative)
4:30	Comments - NCSRP, USB, and state checkoff representatives
5:00	Social Hour
6:00	Dinner
Networking and project meetings on Thursday evening
Friday, November 18
7:00 AM	Continental Breakfast
8:00	Morning announcements
8:15	Glyphosate and SDS (led by X. B. Yang, Iowa State University)
8:45	SDS Management and Extension (led by Daren Mueller, Iowa State University)
9:15	USB SDS research update (led by Silvia Cianzio, Iowa State University) Iowa State University, Southern Illinois University, and the University of Arkansas
9:45 -11:30	Group Discussions and Future Research Planning
10:00	Morning Break
11:45	Comments NCSRP and USB Representatives Meeting Summary/Location and coordinators for 2012 meeting
12:15	Meeting Concludes