US NSF LTER sites US NSF National Ecological

US NSF LTER sites

US NSF National Ecological Observatory Network • New network for addressing major ecological questions, with Infectious Disease as one major theme • Planning for the next 30 years • General website www. neoninc. org • Website with latest reports from topics committees (prior to specifying particular systems) : http: //www. neoninc. org/archive/2005/04/latest_ neon_des. html#more

Long-term foliar infection in tallgrass prairie plants Tallgrass prairie in central USA

Not as flat as a pancake Flint Hills, Kansas, USA

3, 487 Ha Burn Interval Variable Annual 2 year 4 year 10 year 20 year Grazing Bison Cattle KONZA PRAIRIE BIOLOGICAL STATION N

Long-term plant species composition data • Long-term data set with complete plant species cover classes collected in many environments at Konza Prairie • See www. konza. ksu. edu

Sampling scheme within a transect for plant species composition assessment • Five quadrats are located along each transect • In general, four upland transects and four lowland transects are present in each watershed

Precipitation manipulation – Ra. MP project

Most important environmental effects • Burning is not so important across species (during drought years), but is for some particular species • Position on slope is the most important environmental predictor • Grazing effects were quite specific to hostpathogen system • Host frequency dependence was indicated

Overall effects of burning (during 3 drought years)

Effects of burning on rust of Erigeron strigosus Dendy et al. , in preparation

Topographic effect on big bluestem rust • Rates of infection by Puccinia andropogonis are greater for midslope sites than bottom or crest sites (P≤ 0. 05) Midslope Bottom Crest Morgan, Garrett, Todd, and Tisserat (in revision)

Precipitation effects on disease • A community epidemiology approach studying the responses of visually-distinguishable pathogens of 20 dominant tallgrass prairie plant species • Responses to burn return time and topography are less consistent from one host-pathogen system to another and may contribute to stability of plant productivity Garrett et al. (in preparation)

Flowering in Dalea candida as a function of precipitation level and leaf rust infection Garrett et al. (in preparation)

Movement of pathogens between agricultural and natural systems and external pathogen populations Agricultural (Managed) System Environment Host Natural (Unmanaged) System Plant community Environment Pathogen community Pathogen External pathogen community

BYDV infection in native grasses • First report of BYDV/CYDV in these grass species: percentage infection based on at least 50 plants of each species • PAV is the most common strain in wheat, but was not recovered from the grasses at Konza Prairie • In wheat, infection rates by the “tallgrass prairie” strains were common adjacent to prairie but fell off 30 m into wheat fields Grass species PAV MAV RMV RPV SGW Indian grass 0 0 0 Little bluestem 0 4 2 0 58 Switchgrass 0 31 0 0 4 Big bluestem 0 59 0 0 3 Garrett, Dendy, Power, Blaisdell, Alexander, and Mc. Carron 2004 Plant Disease

Susceptibility of native grasses to take-all Grass species Response Big bluestem R Little bluestem R Indian grass R Switchgrass R Sideoats grama S Blue grama S Buffalo grass S • Native grass seedlings showed nearly complete resistance or susceptibility to the takeall pathogen • Exchange between agricultural and natural systems needs study • In grasslands there is the potential for apparent competition via shared pathogens Cox, Garrett, Bockus, and Fang (in review)

Ecological genomics and epidemiology Garrett et al. , in review

In a study of the dominant tallgrass prairie plant species, Andropogon gerardii, we have been able to detect responses to simulated precipitation change in the field using maize microarrays Travers et al. , in review

Systemic acquired resistance • (Need nomenclature for new forms of resistance as they are understood) • Infection with an incompatible pathogen, or virulent pathogen that causes cell death, can make a plant more resistant to subsequent infection by the same or different pathogens – SAR response in Arabidopsis confers resistance to several diseases (Ryals et al. 1996)

Induced systemic resistance • Resistance to pathogens can be influenced by non-pathogenic organisms • Systemic changes in disease resistance in response to colonization by rhizospherecolonizing Pseudomonas have been welldocumented (Iavicoli et al. 2003, Cui et al. 2005) • Dissection of SAR and ISR signaling systems in Arabidopsis indicate they are controlled by different pathways and signaling molecules with some common components

Landscape ecological genomics Garrett et al. , in review