generation of ESTs (expressed sequence tags)

generation of ESTs from early and later stages of proteoid root development

Two cDNA libraries from proteoid roots of -P stressed plants were constructed. A cDNA library of early stages of proteoid root development contained pooled RNA isolated from P-deficient roots and developing proteoid roots from 7 and 10 DAE (days after emergence). At 7 DAE, proteoid roots are not yet visible, so normal roots of -P stressed plants were collected. At 10 DAE immature proteoid roots were collected. A cDNA library of the later developmental stages of proteoid roots was generated with pooled RNA isolated from -P proteoid roots from 12 and 14 DAE. Average cDNA insert size was found to be approximately 1.6 kb. Single pass sequencing resulted in 2121 sequences of good quality with a length of at least 100 bp. Typical sequence lengths of good quality ranged from 400 to 500 bp. Of these 2121 ESTs, 849 sequences derived from cDNA from the early developmental stages (7 and 10 DAE) and 1272 ESTs from the library of more mature proteoid roots (12 and 14 DAE).