Studies on the characterization of rice histidine kinase mutant (Oshk4-2)
Date Issued
2015
Date
2015
Author(s)
Yeh, Jui-En
Abstract
Cytokinin signaling regulates plant growth and development by several environmental cues. The cytokinin receptor, histidine kinase (HK) is responsible for the first component to bind with cytokinin and then activates downstream cytokinin signal transduction. As characterized to have the transmembrane domain in amino acid sequence, cytokinin receptor may serve the sensor for environmental fluctuation. Rice is one of the most important cereal crops in the world and is a heat-sensitive plant during seedling and flowering stages. Heat stress causes intensive change of membrane fluidity. Therefore, this study focuses on whether cytokinin receptors response to heat stress to result in plant phenotype change or different in thermotolerance. By using cytokinin receptor mutant, Oshk4-2, we found that OsHK4 regulates leaf length and leaf angle and serves as the negative regulator on leaf senescence at the seedlings stage. Moreover, defect in OsHK4 significantly decreases the survival rate after heat stress. The induction of the transcript level of cytokinin signaling genes and small heat stress protein (sHSP) are repressed after heat stress treatment in OsHK4 defect mutant. The activity of antioxidant enzymes, ascorbate peroxidase (APX) and glutathione reductase (GR) are reduced and the �IPSII rapid decreased after heat stress in OsHK4 defect mutant. These results suggest OsHK4 regulates early seedling growth and mediates part of CK signaling transduction, antioxidant system and photosynthesis with influence on thermotolerance after heat stress at the seedling stage.
Subjects
Cytokinin signaling
Histidine kinase
Heat stress response
small heat stress proteins
thermotolerance
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-104-R02621115-1.pdf
Size
23.32 KB
Format
Adobe PDF
Checksum
(MD5):658c52ce104a78a2905bc800966811f9