FIG. 2.

Evolutionary distance dendrogram showing the positions of environmental SSU rDNA sequences recovered from rice roots (ARR sequences) and anoxic bulk soil (ABS sequences) from flooded rice microcosms. The positions of sequences are shown in relation to the positions of known members of the Crenarchaeota and environmental sequences retrieved from coastal marine environments (ANTARCTIC 12, SBAR5, and WHAR Q [9]), from a hot spring in the Yellowstone National Park (pJP27, pJP41, pJP78, and pJP 89 [4], as well as pSL12, pSL17, and pSL22 [3]), from shallow-sediment and marsh environments (pGrfC26 and pGrfA4 [17]), and from a forest soil (FFSB2 [21]). The numbers in parentheses indicate whether the environmental sequences were recovered from 84-day-old flooded rice microcosms or 90-day-old flooded rice microcosms. SSU rDNA sequences from Aquifex pyrophilus, from members of the Euryarchaeota, and from members of the “Korarchaeota” were used as outgroup reference sequences. The dendrogram was constructed as described in the legend to Fig. 1. Scale bar = 10% difference in nucleotide sequence positions.