population genetics of puccinia coronata f. sp. avenae hattie dambroski and martin carson usda-ars...

Population Genetics of Puccinia coronata f. sp.

avenae

Hattie Dambroski and Martin CarsonHattie Dambroski and Martin CarsonUSDA-ARS

Cereal Disease LaboratorySaint Paul, MN

Oat Crown Rust

Puccinia Pathway

Objective

To study the diversity and population structure of Puccinia coronata.

• sexual populations in the north

• asexual populations in the south

•DNA isolated from germinated and non-germinated urediniospores

•Five DNA samples isolated from aeciospores

•41 dinucleotide microsatellites

•Target sequence (CA)n

•Highly Polymorphic, allelic diversity ranges from 2 to 22

Microsatellites

Populations

• Northern Populations• MN, ND, SD, WI, NE

• Southern Populations• NC, FL, LA, AL

• Texas

• California

• Foreign Populations• Brazil, Israel, Russia, Egypt, Australia, Mexico, Canada, Uruguay, Turkey, Argentina

Isolates

CA

TX

SD

ND MN

LAFL

NC

Surveyed 75 isolates so far

NE

WI

AL

Statistics

HO ranged from 0.014 to 0.973

HE from 0.166 to 0.742

11 loci are in Hardy-Weinberg equilibrium (P<0.05)

Preliminary Results

AMOVA showed most molecular variance within populations vs. among populations

Neighbor joining tree based on genetic distance

Tree Results

1.Group with little genetic differentiation forming between north, south and Texas populations (asexual pop.)

2.Northern aecial isolates form a group with greater genetic differentiation between isolates (sexual pop.)

3.California isolates forming own group with great genetic differentiation from other groups

Things yet to do…..

•Finish U.S. Isolates

•Screen Foreign Isolates

•Screen Markers on other Rust species

•Analyze data