Font Size: a A A

NCA1 Is Involved In The Process Of Salt Stress Perception In Arabidopsis Thaliana

Posted on:2013-03-18Degree:DoctorType:Dissertation
Country:ChinaCandidate:Y NiuFull Text:PDF
GTID:1220330482468248Subject:Cell biology
Abstract/Summary:PDF Full Text Request
Soil salinity of agricultural land has an adverse impact on agriculture production, and it turns more and more a global environmental concern. Many crucial physiological and biochemical processes of plant will be damaged by high salt and osmotic stresses in varying degrees.However, plants themselves have a series of response and repair mechanisms to keep basal growth and development under high salt stress. So far, many reports focus on the Na+ transporters which mediate ion homeostasis. In addition, plant cells can also accumulate organic osmolytes to tolerate osmotic stress. Moreover, some particular protein complexes can maintain other proteins structure and stabilize membrane composition in the face of elevated salts, and some other proteins or enzymes involved in redox reaction could inhibit or eliminate the reactive oxygen species which may cause cell damage.In fact, the plant response to salt stress contains signal perception, transduction, response and adaptation to environmental changes. Calcium as a second messenger in plant will increase transiently induced by a specific stimulus impulse. And then Ca+ can bind to a large number of distinct functional calcium binding proteins which was applied to the conversion of Ca2+ signals into phosphorylation events or transcriptional responses.In the past three decades, our understanding of how to visually detect the transient alteration of intracellular calcium signal was a difficult problem on technique. Until the early 60s of last century, photo-protein named aequorin derived from a jellyfish Aequorea Victoria was developed gradually into an experimental method to detect intracellular calcium concentration changes in different cell types, it is widely applied in calcium signal research.In this dissertation, author generated about 300,000 independent lines with T-DNA inserted mutant population expressing aequorin of Arabidopsis (col-0) via Agrobacterium tumefaciens mediated transformation method. And screening about 90,000 lines from this T2 generation of T-DNA inserted mutant population via calcium-based aequorin image, we finally isolated a mutant in which intracellular calcium could not increase under salt stress, it was named ncal depending on NaCl induced Calcium increase deficiency mutant. Interestingly, we find that calcium concentration in ncal is not changed specifically under Na+ stress. GFP subcellular localization shows NCA1 is located in plasmamembrane, and GUS analysis indicates it can be expressed all tissues. In addition, the gene complementary lines and over-expressed lines are confirmed that the phenotype of ncal is related with complete NCA1 gene suppression. After the predicated functional motif of NCA1 was point mutated, we found that the normal function of NCA1 needed this predicated functional motif. Subsequently, genetics analysis confirmed NCA1 was a salt stress sensor during initial stage. And the result of basal calcium illustrated that NCA1 could encode a Na+-sensitive sensor which percept the concentration of Na+, and regulate calcium transporters to induce the calcium signal. But the confirmation of this hypothesis is in the progress, the illustration of physiological function of NCA1 will be our final goal. This research we focused on is stress sensors which can specifically percept salt stress during signal initial stage and this result so far has not been reported by others, therefore, it possesses very important scientific significance and potential applied value.
Keywords/Search Tags:ncal mutant, salt stress, Ca2+ signature, calcium sensors, salt-tolerance response
PDF Full Text Request
Related items