RESUMO
Recent work on the fragile fiber mutants of Arabidopsis has identified microtubule-associated proteins that affect the orientation of cellulose microfibrils in cell walls, a major determinant of plant elongation growth. These same proteins are implicated in responses to gibberellin, provoking fresh speculation about how this hormone affects cell elongation and growth.
Assuntos
Arabidopsis/citologia , Arabidopsis/metabolismo , Citoesqueleto/metabolismo , Adenosina Trifosfatases/genética , Adenosina Trifosfatases/metabolismo , Arabidopsis/genética , Katanina , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Microtúbulos/metabolismo , Reguladores de Crescimento de Plantas/metabolismoRESUMO
The lue1 mutant was previously isolated in a bio-imaging screen for Arabidopsis mutants exhibiting inappropriate regulation of an AtGA20ox1 promoter-luciferase reporter fusion. Here we show that lue1 is allelic to fra2, bot1 and erh3, and encodes a truncated katanin-like microtubule-severing protein (AtKSS). Complementation of lue1 with the wild-type AtKSS gene restored both wild-type stature and luciferase reporter levels. Hormonal responses of lue1 to ethylene and gibberellins revealed inappropriate cortical microtubule reorientation during cell growth. Moreover, a fusion between the AtKSS protein and GFP decorated cortical microtubules. A yeast two-hybrid screen with AtKSS as the bait identified proteins related to those involved in microtubule processing, including a katanin p80 subunit and a kinesin ortholog. These results indicate that AtKSS is involved in microtubule dynamics in response to plant hormones.