Comparison of the Fusarium species composition between a New England and Chinese salt marsh affected by dieback and climate change
W. ELMER (1). (1) Connecticut Agricultural Experiment Station, New Haven, CT, U.S.A.
A dieback of <i>Phragmites australis</i> (PA) at Dongtan of Chongmong Island in the Yangtze River estuary near Shanghai, China was found in areas where the invasive <i>Spartina alterniflora</i> (SA) had made serious inroads into PA communities. In contrast, New England dieback of SA occurs in the low marsh while PA remains a vigorous colonizer of the high marsh. <i>Fusarium palustre</i> and <i>F. incarnatum</i> are fungal endophytes/pathogens of SA along the Atlantic and Gulf coasts in and comprised approximately 80 % of the species found. Both species were recovered in greater densities from salt marshes stressed by dieback. Our objectives were to assay PA and SA in dieback and healthy areas on Chongmong Island to determine what species of <i>Fusarium</i> are present. Twenty sites were sampled. Three to five plants per sites were sampled, bulked, washed, and surface-disinfested in 0.53% NaClO for 1 min and rinsed. From these plants, 40 pieces of stems and 20 pieces of roots were placed on Peptone PCNB agar and incubated for 5 days. A single spore from each colony was sub-cultured onto carnation leaf agar for 7-12 days and identified under 200 X magnification. Out of 270 colonies from China, 60% were <i>F. incarnatum</i>, 24% were <i>F. palustre</i>. Given the differences between these sites, it was surprising to find both marshes were dominated by the same two species of endophytic <i>Fusarium</i>. This suggests these species may have been introduced with SA.
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