CHROMOSOME LANDING AT THE ARABIDOPSIS TORNAD01 LOCUS USING AN AFLP-BASED STRATEGY

The Arabidopsis tornadol (trn1) mutation causes severe dwarfism combin ed with twisted growth of all organs. We present a chromosome landing strategy, using amplified restriction fragment length polymorphism (AF LP) marker technology, for the isolation of the TRN1 gene. The recessi ve trn1 mutation was identified in a C24 transgenic line and is locate d 5 cM from a T-DNA insertion. We mapped the TRN1 locus to the bottom half of chromosome 5 relative to visible and restriction fragment leng th polymorphism (RFLP) markers. Recombinant classes within a 3-cM regi on around TRN1 were used to build a high-resolution map in this region , using the AFLP technique. Approximately 300 primer combinations have been used to test about 26000 fragments for polymorphisms, Seventeen of these AFLP markers were identified in the 3-cM region around TRN1. These markers were mapped within this region using individual recombin ants. Four of these AFLP markers co-segregate with TRN1 whereas one ma ps at one recombinant below TRN1. We isolated and cloned three of thes e AFLP markers. These markers identified two yeast artificial chromoso me (YAC) clones, containing the RFLP marker above and the AFLP marker below TRN1, demonstrating that these YACs span the TRN1 locus and that chromosome landing has been achieved, using an AFLP-based strategy.