Rainwater monitoring of rust spores Charlie Barnes USDA-ARS Cereal Disease Laboratory Charlie Barnes USDA-ARS Cereal Disease Laboratory

Rainwater monitoring of rust spores Les J. Szabo Jerry L. Johnson Kim P. Nguyen USDA ARS CDL University of Minnesota Les J. Szabo Jerry L. Johnson Kim P. Nguyen USDA ARS CDL University of Minnesota Funding: USDA- ARS, USB and MNSR&PC Van Bowersox Karen Harlin Illinois State Water Survey NADP/NTN Van Bowersox Karen Harlin Illinois State Water Survey NADP/NTN

Student workers Andrea Carlson Faith Durham Kate Butler Andrea Carlson Faith Durham Kate Butler John Bulter Jackie Koch Josh Rosnow Yibai Li John Bulter Jackie Koch Josh Rosnow Yibai Li

Outline  The real-time PCR assay  Project one: Puccinia graminis spores in rain  Project two: Phakopsora pachyrhizi spores in rain  The real-time PCR assay  Project one: Puccinia graminis spores in rain  Project two: Phakopsora pachyrhizi spores in rain

Fungal 18SITS15.8S ITS2 P. graminis nested assay Rust Probe 18SITS15.8S

P. graminis nested assay  Verify amplicon size  Sequence select positives  Verify amplicon size  Sequence select positives

Project One Puccinia graminis in rain

NADP sites used to monitor P. graminis in rain in 2004

A typical NADP station

P. graminis project outline  Rain is collected weekly at NADP sites  Rain is sent to Illinois and filtered  Filters are dried and sent overnight  Remove debris from filter (day 1)  DNA is extracted (day 2)  Run real-time PCR assay (day 3)  Rain is collected weekly at NADP sites  Rain is sent to Illinois and filtered  Filters are dried and sent overnight  Remove debris from filter (day 1)  DNA is extracted (day 2)  Run real-time PCR assay (day 3)

P. graminis in rain-May 18 Mod. spore load SR field reports

P. graminis in rain-May 25 Mod spore load SR field reports May 18

P. graminis in rain-June 1 Mod spore load SR field reports

P. graminis in rain-June 8 Mod spore load SR field reports 3 weeks later

P. graminis in rain-June 15 Mod spore load SR field reports 3 weeks later

P. graminis in rain-June 22 Mod spore load SR field reports 3 weeks later

P. graminis in rain-July 20 Mod spore load SR field reports

Summary  Detection limit of 1-10 spores  Detect stem rust spores 3 weeks prior to 1 st reported infections consistently along the Puccinia pathway  Regional trends confirms assay  What one would expect from the biology of the organism  Detection limit of 1-10 spores  Detect stem rust spores 3 weeks prior to 1 st reported infections consistently along the Puccinia pathway  Regional trends confirms assay  What one would expect from the biology of the organism

Project Two Phakopsora pachyrhizi in rain Data for 2005 and 2006

FungalPhp specific* 18SITS15.8S ITS2 Ph. pachyrhizi nested assay Rust Probe 18SITS15.8S * Frederick et al. 2002

US soybean production 2005 by county

NADP sites used to monitor Ph. pachyrhizi in rain

Weekly trends: Percent Positive MayJuneJulySept.Aug Oct.

Comparison of 2005 & 2006 Geographical Distribution (May-Aug)

Comparison of 2005 & 2006 Geographical Distribution (May-Aug)

Comparison of 2005 & 2006 Geographical Distribution (May-Aug)

Comparison of 2005 & 2006 Geographical Distribution (May-Aug)

ASR field reports 2005

ASR field reports boundry

Summary  Ph. pachyrhizi spores were detected throughout the soybean growing region of the U.S.  Frequency and spore load increased in  Detection of spores in rain further north in 2006 matches increase in field reports.  Rain data is consistent with ASR becoming established in Southern U.S. and the Gulf Coast region of Mexico and Central America.  Ph. pachyrhizi spores were detected throughout the soybean growing region of the U.S.  Frequency and spore load increased in  Detection of spores in rain further north in 2006 matches increase in field reports.  Rain data is consistent with ASR becoming established in Southern U.S. and the Gulf Coast region of Mexico and Central America.

Overall summary  So far, detect 2 rust pathogens in rain  Adaptable assay system  Currently have probes for:  P. coronata (7 different groups)  P. recondita f.sp secalis  P. striiformis  P. triticina  And others  So far, detect 2 rust pathogens in rain  Adaptable assay system  Currently have probes for:  P. coronata (7 different groups)  P. recondita f.sp secalis  P. striiformis  P. triticina  And others