Symbioses: Plant, Animal, and Microbe Interactions
Shipunov, Alexey B. , Raghavendra, Anil Kumar , Newcombe, George .
Fungal endophytes of spotted knapweed: taxonomical, geographical and chronological analysis.
The biology and diversity of plant fungal endophytes of spotted knapweed (Centaurea stoebe L., Asteraceae) is important both theoretically and practically. We sampled seed-borne fungal endophytes of spotted knapweed from both native and invaded ranges: U.S., Canada end Europe from Southern France to Urals. More that 2700 fungal isolates from 105 knapweed localities were obtained. These strains were selected for subsequent cultivation, determined by morphology (mostly to generic level) and selected again for DNA sequence identification (two ITS regions with 5.8S RNA, and “Alternaria a 1” gene sequences were used) via BLAST search through the Gen Bank.
Up to date, we determined 75 different fungal haplotypes (unique combinations of ITS and “Alternaria a 1”). They belong to 7 classes of ascomycetes, more than 80% to Dothideomycetes. The most abundant genera are mitosporic fungi from Alternaria and Cladosporium genera. In several cases, putative new taxa were described. In all, native region (Eurasia) have more fungal diversity than exotic region, despite of the prevalence of Alternaria in most Eurasian sites. For comparison with knapweed, we also tried to obtain endophytic fungi from native American Asteraceae: Aster jessicae, Helianthus annuus, Cirsium brevifolium, C. magnificum and Saussurea americana. These species have quite different endophyte flora, along with two fescue species, Festuca idahoensis and F. ovina, which also used for comparison.
Some knapweed sites have 0% of fungal isolation, our preliminary research shows that there is putative relation between late-summer and autumn rains and isolation frequencies. In several cases, we repeated the sampling from the same location one or two years after and found that endophyte flora composition seems to be stable.
The comparison of seed sampling an cultivation-independent method for determining endophytes is on the way.
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1 - University of Idaho, Department of Forest Resources, Moscow, Idaho, 83844-1133, USA
2 - University of Idaho, Department of Forest Resources, Moscow, Idaho, 83844, USA
Presentation Type: Oral Paper:Papers for Topics
Location: Continental B/Hilton
Date: Wednesday, July 11th, 2007
Time: 2:30 PM