title: Core Mechanisms Regulating Developmentally Timed and Environmentally Triggered Abscission.
abstract: Drought-triggered abscission is a strategy used by plants to avoid the full consequences of drought; however, it is poorly understood at the molecular genetic level. Here, we show that Arabidopsis (Arabidopsis thaliana) can be used to elucidate the pathway controlling drought-triggered leaf shedding. We further show that much of the pathway regulating developmentally timed floral organ abscission is conserved in regulating drought-triggered leaf abscission. Gene expression of HAESA (HAE) and INFLORESCENCE DEFICIENT IN ABSCISSION (IDA) is induced in cauline leaf abscission zones when the leaves become wilted in response to limited water and HAE continues to accumulate in the leaf abscission zones through the abscission process. The genes that encode HAE/HAESA-LIKE2, IDA, NEVERSHED, and MAPK KINASE4 and 5 are all necessary for drought-induced leaf abscission. Our findings offer a molecular mechanism explaining drought-triggered leaf abscission. Furthermore, the ability to study leaf abscission in Arabidopsis opens up a new avenue to tease apart mechanisms involved in abscission that have been difficult to separate from flower development as well as for understanding the mechanistic role of water and turgor pressure in abscission.
authors.affiliation: Division of Biological Sciences and Interdisciplinary Plant Group, University of Missouri, Columbia, Missouri 65211 rpatharkar@gmail.com.
authors.forename: O Rahul
authors.identifier: 0000-0002-1242-6549
authors.initials: OR
authors.lastname: Patharkar
authors.affiliation: Division of Biological Sciences and Interdisciplinary Plant Group, University of Missouri, Columbia, Missouri 65211.
authors.forename: John C
authors.identifier: 0000-0002-2050-1641
authors.initials: JC
authors.lastname: Walker
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D055864:Droughts; D035264:Flowers / Q000235:genetics* / Q000502:physiology; D020690:GTPase-Activating Proteins / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling / Q000379:methods; D018506:Gene Expression Regulation, Plant; D008856:Microscopy, Fluorescence; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D018515:Plant Leaves / Q000235:genetics* / Q000502:physiology; D030821:Plants, Genetically Modified; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000235:genetics; D013997:Time Factors; D014867:Water / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D020690:GTPase-Activating Proteins; C512213:IDA protein, Arabidopsis; C544765:NEV protein, Arabidopsis; D014867:Water; C089427:RLK5 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases; D020928:Mitogen-Activated Protein Kinases