cDNA and genomic DNA clonings of chalcone synthase from Pueraria lobata

Four cDNAs encoding chalcone synthase (CHS), the key enzyme in flavonoid biosynthesis, were isolated from Pueraria lobata cells challenged with yeast extract elicitor using bean CHS cDNA as a probe. The longest clone contained a complete open reading frame of 1170 bp which would predict a protein of about 43 kDa. The others were not full-length clones. Using isolated cDNA as a probe, Southern blot hybridization of genomic DNA fragments revealed the presence of multiple CHS genes in the P. lobata genome. We cloned and sequenced one CHS genomic clone, gCHS14, whose 5' untranslated region showed homology with the bean CHS gene CHS15 and included the several reported sequences characteristic of stress response.