19Expression of PsIPTs at the 2nd Node after Decapitation 0.5432156915182412PsIPT1PsIPT2rRNAtime after decapitation (hr)
20Is IPT expression repressed ? excise the segments3hr after decapitationIPT is expressedincubate in MES bufferwith or without IAAIs IPT expression repressed ?1cmexcise the segmentsfrom intact seedlingsIPT is NOT expressedincubate in MES bufferwith or without IAAIs IPT expressed?
21PsIPTs Expression was Repressed by IAA 12345IAA Free10-5 M IAAPsIPT1PsIPT2rRNAincubation time (hr)
22Is IPT expression repressed? excise the segmentsafter 3hr decapitationIPT is expressedincubate in MES bufferwith or without IAAIs IPT expression repressed?1cmexcise the segmentsfrom intact seedlingsIPT is NOT expressedincubate in MES bufferwith or without IAAIs IPT expressed?
23PsIPTs Expression was Induced in IAA Free Buffer 10-5 M IAA165432incubation time (hr)987PsIPT1PsIPT2rRNA
2410-5 M IAA IAA Free 10-5 M IAA excise the segments after 3hr decapitationIPT is expressedincubate in MES bufferwith or without IAARepress IPT expression?1cmIAA Free1234510-5 M IAA12345IAA Free10-5 M IAA165432987165432excise the segmentsfrom intact seedlingsNot IPT expressionincubate in MES bufferwith or without IAAIPT express?
25PsIPTs Expression was Repressed by IAA Transported Basipetally in the Stem PsPIN1＋IAALanoline paste w or w/o IAA after decapitation3hrIs IPT expression repressed?1cm
31in Transformants harboring pPsIPT2::GUS GUS Transcripts Deceased by Auxinin Transformants harboring pPsIPT2::GUSIAA Free10-5M IAA12345incubation time (hr)
32Cytokinin Levels in the Stems and Axillary Buds after Decapitation
33Cytokinin Levels in the Excised Segments treated with/without IAA 100200300iPMPiPAiPt-ZMPt-ZRt-zeatin0h3h6h-IAA+IAA1002003000h3h6h(p mol/ gFW)(p mol/ gFW)iPMPiPAiPt-ZMPt-ZRt-zeatinexcised the segmentsput on the agar plate± 1%(w/v) IAA treatment
34ConclusionOne role of auxin in apical dominance is to repress the PsIPTs expression; local cytokinin biosynthesis in the nodal stem is negatively regulated by auxin through the control of IPT expression.Cytokinin, which is thought to be derived from the roots so far, is locally biosynthesized in the stem rather than in the roots after decapitation.
35PsIPTs Expression was Repressed by Basipetally Transported IAA in the Stem PsPIN1＋IAA1% (w/v) IAAafter decapitation3hrIs IPT expression repressed?1cm
36Effect of IAA Applied to the Stump on PsPIN1 Expression actin1234(cm)124(hours)1234IAA
37Can IAA from Axillary Buds induce PsPIN1? BiosynthesisdecapitatedintactIAAIAA3hr9hr0hr
41Cytokinin oxidase cDNAs were isolated from the stem 12 hr after decapitation. PsCKX1：was constantly expressed in stem before and afterdecapitation,was not induced by auxin.PsCKX2：was increased in stem after decapitationwas induced by auxin.
42Expression of PsCKX2 in Pea Stem 1020304080120decapitationTIBA treatmentRelative amounts of mRNATime after treatment (hr)
43PsCKX2 Expression in Excised Pea stem by Auxin 10203040(x 103)Relative amounts of mRNA+NAA-NAATime after treatment (hr)
44PsCKX2 Expression in Pea stem - NAA4080120Relative amounts of mRNA1020Time after treatment (hr)
45PsCKX2 Expression in Excised Pea stem by Auxin 10203040(x 103)Relative amounts of mRNA+NAA-NAATime after treatment (hr)
52Effect of Striolactone GR24 on outgrowth of axillary bud after decapitation control
53Apical dominance Nagoya University ・Mina TANAKA ・Sae SATO-SHIMIZU ・Aiko ISHIWATA・Yuka MADOKARIKEN・Mikiko KOJIMA・Hitoshi SAKAKIBARAThis work was done by my laboratory in Nagoya University and Dr.Sakakibara group in RIKEN.Thank you for your attention.