ESTs from different tissues - a quick guide

Last updated, 15/08/2000

There are now nearly 110,000 Arabidopsis EST sequences in the EMBL database, all of which are available through AGR. The majority of these ESTs have been released since the last full release of EMBL (release 63) and are only available if you search EMBL's daily update files. Most of these sequences have a 'tissue_type' qualifier listed in their database annotation. For the 79,163 EST sequences which have this information, the tissue types are as follows:

Number of ESTs   Tissue type description
========================================
18,947           roots
15,767           above-ground organ
12,752           green siliques
10,738           seed
 5,827           flower buds
 2,351           rosette
 2,045           seedling hypocotyl
 1,647           whole seedlings of A. thaliana ecotype
 1,161           liquid-cultured seedlings     
 1,084           cell suspension culture  of ecotype columbia
 1,059           inflorescence
 1,006           leaves, flowering plants
   990           Flower buds of A.thaliana ecotype columbia C24
   707           sliced leaves of A.thaliana ecotype columbia
   678           Green siliques of A.thaliana ecotype columbia
   642           leaves, seedlings
   346           Dry seeds of A.thaliana ecotype columbia
   333           seedlings, leaf and root
   325           green shoots of A.thaliana ecotype columbia
   241           roots of nitrate treated liquid-cultured A.thaliana
   201           inflorescence with predominately younger flower buds
   105           Flowering tips of ecotype Landsberg erecta
    60           cell suspension culture of A.thaliana
    49           whole plant
    27           Excised pieces of roots containing nematode feeding sites
    20           inflorescence apex with young flowers (<~Stage 9)
    17           Above-ground organ from two to six-week old plants
    16           Germinating seeds
     6           7 day old germinated etiolated seeds
     3           immature siliques
     1           shoots

Please note that these tissue-type descriptions are listed exactly as they appear in the EMBL record. So presumably 'green siliques' and 'Green siliques of A.thaliana ecotype columbia' reflect the same tissue, though they are listed separately above. Also note that of these 79,163 EST sequences, 62,569 are sequences that have been released since the last full release of the EMBL database.

Given the speed at which new EST sequences are being released to EMBL it is highly likely that by the time you read this, these figures will be out of date!

This information will be made available as part of the Arabidopsis Genome Resource (AGR). For now, the information will be posted on the AGR web page (http://ukcrop.net/agr/) and in due course the database will be rebuilt to reflect this useful information and you will be able to search EST sequences by tissue type.