Data Access

G. intraradices sequences analyzed originated from one of several sources. Two libraries were obtained from material obtained by culture of G. intraradices in a two-compartment system with transformed Daucus carota host cells (Sawaki, [104] and Harrison, unpublished). The two libraries were prepared independently, using different strains and cloning vectors, though both sampled from transcripts expressed in extraradical mycelia. Libraries were prepared from mycelia collected from a compartment isolated from plant host cells, and so are not expected to have plant transcripts present.

A third library represents transcripts obtained from axenic germinating spores and germ tubes (Lammers, unpublished). An axenic Medicago truncatula root-hair enriched library (Long, [34]) provided a negative control, in which no fungal transcripts are expected to be present. The four axenic libraries, three from G. intraradices and one from Medicago, are summarized in Table 4.1.

Transcripts from the Harrison library are being prepared for GenBank submission (as of April, 2001 AD). Except for transcripts from the Harrison library, all sequences were obtained from the GenBank database using the Entrez retrieval tool [13,126,127], in a manner similar to that described in Section 2.3.1.

Table 4.1: Test sets: Number of transcript sequences (n) and nucleotides (nt) in raw and filtered (trimmed N-rich regions, poly-A and poly-T sites, and screened to remove ribosomal DNA and remaining sequences shorter than 100 nt) sets of sequences. The investigator associated with each library and the tissue type from which each library was prepared are also indicated.

INVESTIGATOR	TISSUE	RAW		FILTERED
		n	nt	n	nt
Glomus intraradices
Harrison	mycelia	770	630,841	362	148,492
Lammers	spores	291	143,658	174	56,246
Sawaki	mycelia	166	73,327	165	63,634
Medicago truncatula
Long	root hairs	899	539,719	899	511,604