Functional study of Receptor for Activated C-Kinase 1 (RACK1) in drought stress response in Arabidopsis thaliana
Date Issued
2014
Date
2014
Author(s)
Chang, Yi-Yun
Abstract
Receptor for Activated C-Kinase 1 (RACK1) is a 36-kDa protein, which is highly conserved in both animals and plants. There are three RACK1 genes in Arabidopsis thaliana, namely RACK1A (At1g18080), RACK1B (At1g48630) and RACK1C (At3g18130). AtRACK1 is involved in multiple hormone responses, developmental processes, and associated with 40S ribosomes in Arabidopsis. Notably, RACK1 is regarded as a versatile scaffold protein which serves as a nexus for multiple signal transduction pathways. Moreover, AtRACK1 plays a negative regulator role under abscisic acid (ABA) responses. However, the specific interactions between AtRACK1 and its binding partners are still unclear. Some proteins and transcription factors that can interact with AtRACK1A were identified by yeast two-hybrid screen, including Translationally Controlled Tumor Protein (TCTP). Furthermore, yeast two-hybrid and bimolecular fluorescence complementation were used to study the interactions between TCTP and RACK1A, and results confirmed that RACK1A interacts with TCTP directly. Protein sequence analysis revealed that a short sequence containing 10 amino acids only exists in dicots. After generating the AtRACK1A overexpression line and isolating the rack1 mutant line, we found AtACK1A participates in roots and rosette leaves development based on phenotype. On the other hand, AtRACK1A expression was down regulated by 20% mannitol treatment. Furthermore, some drought response marker genes that are regulated by ABA are highly expressed in rack1a. After ABA treatment, rack1a showed greater ABA-mediated stomatal closure. We also found that the rack1a showed greatly enhanced tolerance to drought. In summary, these results showed that AtRACK1A not only positively can regulate plant development but also imply that AtRACK1A may negatively participate in the drought stress tolerance.
Subjects
RACK1
鷹架蛋白
氣孔
離層酸
TCTP
乾旱
Type
thesis
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