title: Genetic variation in yield under hot ambient temperatures spotlights a role for cytokinin in protection of developing floral primordia.
abstract: Unusually hot ambient temperatures (HAT) can cause pre-anthesis abortion of flowers in many diverse species, limiting crop production. This limitation is becoming more substantial with climate change. Flower primordia of passion fruit (Passiflora edulis Sims) vines exposed to HAT summers, normally abort. Flower abortion can also be triggered by gibberellin application. We screened for, and identified a genotype capable of reaching anthesis during summer as well as controlled HAT conditions, and also more resistant to gibberellin. Leaves of this genotype contained higher levels of endogenous cytokinin. We investigated a possible connection between higher cytokinin levels and response to gibberellin. Indeed, the effects of gibberellin application were partially suppressed in plants pretreated with cytokinin. Can higher cytokinin levels protect flowers from aborting under HAT conditions? In passion fruit, flowers at a specific stage showed more resistance in response to HAT after cytokinin application. We further tested this hypothesis in Arabidopsis. Transgenic lines with high or low cytokinin levels and cytokinin applications to wild-type plants supported a protective role for cytokinin on developing flowers exposed to HAT. Such findings may have important implications in future breeding programmes as well as field application of growth regulators.
authors: The Institute for Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot, 76100, Israel.
authors: Shiri
authors: S
authors: Sobol
authors: Noam
authors: N
authors: Chayut
authors: Nahum
authors: N
authors: Nave
authors: Dinesh
authors: D
authors: Kafle
authors: Martin
authors: M
authors: Hegele
authors: Rina
authors: R
authors: Kaminetsky
authors: Jens N
authors: JN
authors: Wünsche
authors: Alon
authors: A
authors: Samach
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000502:physiology; D003583:Cytokinins / Q000494:pharmacology*; D035264:Flowers / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development*; D005638:Fruit / Q000187:drug effects / Q000235:genetics; D014644:Genetic Variation; D005838:Genotype; D005875:Gibberellins / Q000494:pharmacology; D018869:Heat-Shock Response / Q000187:drug effects / Q000235:genetics; D006358:Hot Temperature; D008954:Models, Biological; D029598:Passiflora / Q000187:drug effects / Q000235:genetics* / Q000502:physiology; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism; D030821:Plants, Genetically Modified
chemical_list: D003583:Cytokinins; D005875:Gibberellins
keywords: Arabidopsis; Passiflora edulis; flower development; gibberellins; natural variation; off-season flowering; plastochron.