biostudies-literatureKaszler NJános Bolyai Research Scholarship of the Hungarian Academy of SciencesNew National Excellence Program of the Ministry for Innovation and TechnologyNational Research, Development, and Innovation Fund454https://www.ebi.ac.uk/biostudies/studies/S-EPMC9920396biostudies-literatureUnknown12(3)Lateral root primordia (LRPs) of Arabidopsis can be directly converted to shoot meristems (SMs) by the application of exogenous cytokinin. Here, we report that Arabidopsis POLYAMINE OXIDASE 5 (AtPAO5) contributes to this process, since the rate of SM formation from LRPs was significantly lower in the <i>pao5-2</i> knockout mutant. Furthermore, the presented experiments showed that AtPAO5 influences SM formation via controlling the thermospermine (T-Spm) level. Gene expression analyses supported the view that the <i>pao5-2</i> mutation as well as exogenous T-Spm downregulate the expression of the class 3 haemoglobin coding genes <i>AtGLB1</i> and <i>AtGLB2</i>. AtGLB1 and 2 have been reported to augment cytokinin sensitivity, indirectly inhibiting the expression of type-A ARABIDOPSIS RESPONPlants (Basel, Switzerland)Absence of Arabidopsis Polyamine Oxidase 5 Influences the Cytokinin-Induced Shoot Meristem Formation from Lateral Root Primordia.PMC9920396FK 12899700580/19/8UNKP-21-5-SZTE-587Kaszler NFeher AMolnar ABenko PGemes KZambori AfalseAbsence of Arabidopsis Polyamine Oxidase 5 Influences the Cytokinin-Induced Shoot Meristem Formation from Lateral Root Primordia.Lateral root primordia (LRPs) of Arabidopsis can be directly converted to shoot meristems (SMs) by the application of exogenous cytokinin. Here, we report that Arabidopsis POLYAMINE OXIDASE 5 (AtPAO5) contributes to this process, since the rate of SM formation from LRPs was significantly lower in the <i>pao5-2</i> knockout mutant. Furthermore, the presented experiments showed that AtPAO5 influences SM formation via controlling the thermospermine (T-Spm) level. Gene expression analyses supported the view that the <i>pao5-2</i> mutation as well as exogenous T-Spm downregulate the expression of the class 3 haemoglobin coding genes <i>AtGLB1</i> and <i>AtGLB2</i>. AtGLB1 and 2 have been reported to augment cytokinin sensitivity, indirectly inhibiting the expression of type-A ARABIDOPSIS RESPON2023-01-01T00:00:00Z2023 Jan2025-04-25T19:17:47.792Z2025-04-06T07:57:34.474ZS-EPMC99203963677153910.3390/plants12030454