title: Ethylene and auxin biosynthesis and signaling are impaired by methyl jasmonate leading to a transient slowing down of ripening in peach fruit.
abstract: Peach (Prunus persica) was chosen as a model to further clarify the physiological role of jasmonates (JAs) during fruit ripening. To this aim, the effect of methyl jasmonate (MJ, 0.88 mM), applied at a late stage (S3) of fruit development under field conditions (in planta), on the time-course of fruit ripening over a 14-day period was evaluated. As revealed by a non-destructive device called a DA-meter, exogenously applied MJ impaired the progression of ripening leading to less ripe fruit at harvest. To better understand the molecular basis of MJ interference with ripening, the time-course changes in the expression of ethylene-, cell wall-, and auxin-related genes as well as other genes (LOX, AOS and bZIP) was evaluated in the fruit mesocarp. Real-time PCR analyses revealed that transcript levels of ethylene-related genes were strongly affected. In a first phase (days 2 and/or 7) of the MJ response, mRNAs of the ethylene biosynthetic genes ACO1, ACS1 and the receptor gene ETR2 were strongly but transiently down-regulated, and then returned to or above control levels in a second phase (days 11 and/or 14). Auxin biosynthetic, conjugating, transport and perception gene transcripts were also affected. While biosynthetic genes (TRPB and IGPS) were up-regulated, auxin-conjugating (GH3), perception (TIR1) and transport (PIN1) genes were transiently but strongly down-regulated in a first phase, but returned to control levels subsequently. Transcript levels of two JA-related genes (LOX, AOS) and a developmentally regulated transcription factor (bZIP) were also affected, suggesting a shift ahead of the ripening process. Thus, in peach fruit, the transient slowing down of ripening by exogenous MJ was associated with an interference not only with ethylene but also with auxin-related genes.
authors.affiliation: Department of Fruit Tree and Woody Plant Sciences, University of Bologna, Via Fanin 46, 40127 Bologna, Italy.
authors.forename: Alvaro
authors.initials: A
authors.lastname: Soto
authors.forename: Karina B
authors.initials: KB
authors.lastname: Ruiz
authors.forename: Vanina
authors.initials: V
authors.lastname: Ziosi
authors.forename: Guglielmo
authors.initials: G
authors.lastname: Costa
authors.forename: Patrizia
authors.initials: P
authors.lastname: Torrigiani
mesh_terms: D000085:Acetates / Q000494:pharmacology*; D002473:Cell Wall / Q000378:metabolism; D003517:Cyclopentanes / Q000494:pharmacology*; D015536:Down-Regulation; D005030:Ethylenes / Q000378:metabolism*; D005638:Fruit / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D007210:Indoleacetic Acids / Q000378:metabolism*; D054883:Oxylipins / Q000494:pharmacology*; D010940:Plant Proteins / Q000235:genetics; D027861:Prunus / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics; D018749:RNA, Plant / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D036226:Seedlings / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D015398:Signal Transduction; D013997:Time Factors; D015854:Up-Regulation
chemical_list: D000085:Acetates; D003517:Cyclopentanes; D005030:Ethylenes; D007210:Indoleacetic Acids; D054883:Oxylipins; D010940:Plant Proteins; D012333:RNA, Messenger; D018749:RNA, Plant; C072239:methyl jasmonate; C036216:ethylene