Molecular Cloning andCharacterization ofSenescence- Related GenesfromCarnation Flower Petals1

Thesenescence ofcarnation (Dianthus caryophyllus L.)flower petals isassociated withincreased production ofethylene which plays animportant role inregulating this developmental event. Threesenescence-related cDNAclones wereisolated froma cDNAlibrary prepared frommRNAisolated fromsenescing petals. ThesecDNAsarerepresentative oftwoclasses ofmRNAs whichincrease inabundance insenescing petal tissue. The mRNAforoneclass ispresent atlowlevels during theearly stages ofdevelopment andbegins toaccumulate inmature petals prior totheincrease inethylene production. Theaccumulation of this mRNAisreduced, butnoteliminated, inpetals treated with aminooxyacetic acid, aninhibitor ofethylene biosynthesis, or silver thiosulfate, anethylene action inhibitor. Incontrast, expression ofthesecond class ofmRNAsappears tobehighly regulated byethylene. ThesemRNAsarenotdetectable prior totherise in ethylene production andincrease inabundance inparallel with theethylene climacteric. Furthermore, expression ofthese mRNAsissignificantly inhibited bybothaminooxyacetic acidand silver thiosulfate. Expression ofthese mRNAsinvegetative and floral organs waslimited tofloral tissue, andpredominantly to senescing petals.