cDNA microarry analysis on peach fruit

Abstract

Two cDNA libraries were constructed from peach fruit: young / suitable for harvest. A cDNA microarray was made using about 1,500 clones randomly picked up. Target mRNAs were purified from fruits of 10 d, 1, 2.5 and 4 months after blooming as well as leaves just after flowering time. Using these system, about one tenth of cDNA clones varying expression levels were studied. i) Down regulating: polyphenol oxidase, proteinase inhibitor etc., ii) up regulating: antimicrobial peptide homologue, invertase inhibitor etc., iii) weak in mid stage: a transcription factor. A cDNA clone belongs to group i), PF10056 encodes a protein having four times of 28 amino acids repeat motif. Although its function is not clear, expression level was very high until 2.5 months.