ISBN 9783843941273

978-3-8439-4127-3, Reihe Biologie

Eva-Maria Gerlach
Physiological, molecular and ultrastructural properties define saul1 as an autoimmune mutant

207 Seiten, Dissertation Universität Hamburg (2019), Softcover, A5

Zusammenfassung / Abstract

In order to face constant biotic attacks, plants have developed diverse adaption and regulation mechanisms, such as a multilayer immune system to fend off all kinds of plant pathogens. The plant immune system is tightly controlled to prevent defective actions or an autoimmune response. In Arabidopsis thaliana, autoimmunity is characterized by growth defects such as dwarfism and the occurrence of macroscopic lesions, as well as by constitutive expression of PR genes, and by increased resistance against pathogens. SAUL1 encodes a PUB-ARM E3 ubiquitin ligase that regulates senescence and cell death.

In this study, we show that the phenotype of the saul1-1 knockout mutant plant is dependent on temperature and relative humidity and that the saul1-1 mutant resembles an autoimmune mutant. The saul1-1 leaf cells demonstrate ultrastructural changes of chloroplasts as well as massive cell wall depositions consisting of callose and lignin. These cell wall depositions can be found in several other autoimmune mutants when grown at low temperature and could be another common feature of autoimmunity in Arabidopsis thaliana. Our findings indicate a role of SAUL1 in early plant immunity signaling upstream of the EDS1/PAD4/SAG101 regulatory node.