Smut fungus (Langdonia walkerae) incidence is lower in two bunchgrass species (Aristida stricta and A. beyrichiana) after fires early in the year.

Autor: Fill JM; School of Forest, Fisheries, and Geomatics Sciences, University of Florida, Gainesville, FL, 32611., Meadows I; Department of Entomology and Plant Pathology, Mountain Research Station, North Carolina State University, Waynesville, NC, 28786., Walker JL; US Forest Service Southern Research Station, Clemson, SC, 29631., Crandall RM; School of Forest, Fisheries, and Geomatics Sciences, University of Florida, Gainesville, FL, 32611., Kerrigan JL; Department of Plant and Environmental Sciences, Clemson University, Clemson, SC, 29634.
Jazyk: angličtina
Zdroj: American journal of botany [Am J Bot] 2024 Feb; Vol. 111 (2), pp. e16286. Date of Electronic Publication: 2024 Feb 17.
DOI: 10.1002/ajb2.16286
Abstrakt: Premise: In frequently burned southeastern USA pine-grassland communities, wiregrass (Aristida stricta and A. beyrichiana) are dominant bunchgrasses whose flowers are infected during flowering by a smut fungus (Langdonia walkerae). We hypothesized that because prescribed fire timing affects wiregrass flowering patterns, it could affect smut incidence (occurrence of smut on plants) and severity of infection in inflorescences and spikelets. Because soil order could influence plant susceptibility, we hypothesized that these patterns would differ between soil orders. We hypothesized differences between species as representative of geographic variation in this ecosystem.
Methods: We surveyed the incidence and severity of L. walkerae in wiregrass populations (85 populations at 14 sites) that had been prescription burned at different times during the previous year. We used binomial regressions to test whether incidence and severity differed by burn day, soil order, or species, with site as a random effect.
Results: Fires that occurred in the winter were associated with significantly lower incidence than fires later in the year (as the months progressed into summer). Plants growing on Spodosol soils were significantly less likely to be infected than those on other soils. More variation in incidence, however, was explained by site, suggesting that site-specific characteristics were important. Smut severity in inflorescences and spikelets was greater overall in populations of A. stricta than in southern populations (A. beyrichiana).
Conclusions: Our findings indicate that fire timing and soil order affect L. walkerae incidence in wiregrass plants, but neither appears to be associated with greater severity. Patterns of smut infection are related to site history and geographic variation.
(© 2024 Botanical Society of America.)
Databáze: MEDLINE
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