title: Over-expression of Arabidopsis Bax inhibitor-1 delays methyl jasmonate-induced leaf senescence by suppressing the activation of MAP kinase 6.
abstract: Methyl jasmonate (MeJA) is an important signalling molecule that has been reported to be able to promote plant senescence. The cell death suppressor Bax inhibitor-1 (BI1) has been found to suppress stress factor-mediated cell death in yeast and Arabidopsis. However, the effect and the genetic mechanism of Arabidopsis thaliana BI1 (AtBI1) on leaf senescence remain unclear. It was found here that the AtBI1 mutant, atbi1-2 (a gene knock-out), showed accelerated progression of MeJA-induced leaf senescence, while the AtBI1 complementation lines displayed similar symptoms as the WT during the senescence process. In addition, over-expression of the AtBI1 gene delayed the onset of MeJA-induced leaf senescence. Further analyses showed that during the process of MeJA-induced senescence, the activity of MPK6, a mitogen-activated protein kinase (MAPK), increased in WT plants, whereas it was significantly suppressed in AtBI1-overexpressing plants. Under the MeJA treatment, cytosolic calcium ([Ca(2+)](cyt)) functioned upstream of MPK6 activation and the elevation of [Ca(2+)](cyt) was reduced in AtBI1-overexpressing leaves. These results suggested a role of AtBI1 over-expression in delaying MeJA-induced leaf senescence by suppressing the [Ca(2+)](cyt)-dependent activation of MPK6, thus providing a new insight into the function and mechanism of AtBI1 in plant senescence.
authors.affiliation: MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, China.
authors.forename: Haiyun
authors.initials: H
authors.lastname: Yue
authors.forename: Shengjun
authors.initials: S
authors.lastname: Nie
authors.forename: Da
authors.initials: D
authors.lastname: Xing
mesh_terms: D000085:Acetates / Q000494:pharmacology; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D002118:Calcium / Q000032:analysis / Q000378:metabolism; D020013:Calcium Signaling / Q000502:physiology; D016923:Cell Death; D016922:Cellular Senescence; D002734:Chlorophyll / Q000378:metabolism; D003517:Cyclopentanes / Q000494:pharmacology; D004789:Enzyme Activation / Q000502:physiology; D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D055786:Gene Knockout Techniques; D020935:MAP Kinase Signaling System / Q000502:physiology*; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D048053:Mitogen-Activated Protein Kinase 6 / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D008954:Models, Biological; D054883:Oxylipins / Q000494:pharmacology; D010937:Plant Growth Regulators / Q000494:pharmacology; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D030821:Plants, Genetically Modified; D017384:Sequence Deletion; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D013997:Time Factors
chemical_list: C491862:ATBI-1 protein, Arabidopsis; D000085:Acetates; D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D008565:Membrane Proteins; D054883:Oxylipins; D010937:Plant Growth Regulators; D002734:Chlorophyll; C072239:methyl jasmonate; D048053:Mitogen-Activated Protein Kinase 6; D002118:Calcium