Natural Variation in 9-Cis-Epoxycartenoid Dioxygenase 3 and ABA Accumulation
Name
Kalladan et al Plant Phys 2019.pdf
Description
Accepted version
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312.97 KB
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Author(s)
Kalladan, Rajesh
Lasky, Jesse R.
Sharma, Sandeep
Kumar, M. Nagaraj
Juenger, Thomas E.
Des Marais, David Lee
Verslues, Paul E.
Date Issued
February 2019
Journal
Plant Physiology
Publisher
American Society of Plant Biologists (ASPB)
Citation
Kalladan, Rajesh et al. "Natural Variation in 9-Cis-Epoxycartenoid Dioxygenase 3 and ABA Accumulation." Plant Physiology 179, 4 (February 2019): 1620-1631 © 2019 American Society of Plant Biologists
Version
Author's final manuscript
Abstract
The stress hormone abscisic acid (ABA) is critical for drought resistance; however, mechanisms controlling ABA levels are unclear. At low water potential, ABA accumulation in the Arabidopsis (Arabidopsis thaliana) accession Shahdara (Sha) was less than that in Landsberg erecta (Ler) or Columbia. Analysis of a Ler 3 Sha recombinant inbred line population revealed a single major-effect quantitative trait locus for ABA accumulation, which included 9-cis-epoxycarotenoid dioxygenase3 (NCED3) as a candidate gene. NCED3 encodes a rate-limiting enzyme for stress-induced ABA synthesis. Complementation experiments indicated that Sha has a reduced-function NCED3 allele. Compared with Ler, Sha did not have reduced NCED3 gene expression or protein level but did have four amino acid substitutions within NCED3. Sha differed from Ler in the apparent molecular mass of NCED3, indicative of altered NCED3 proteolytic processing in the chloroplast. Site-directed mutagenesis demonstrated that substitution at amino acid 271 was critical for the altered NCED3 molecular mass pattern, while the other Sha NCED3 polymorphisms were also involved in the reduced ABA accumulation. Sha did not have a reduced level of thylakoidbound NCED3 but did differ from Ler in the apparent molecular mass of stromal NCED3. As Sha was not impaired in known factors critical for NCED3 function in ABA synthesis (expression, chloroplast import, and thylakoid binding), the differences between Ler and Sha NCED3 may affect NCED3 activity or other factors influencing NCED3 function. These results identify functionally important sites on NCED3 and indicate a complex pattern of NCED3 posttranslational regulation in the chloroplast.
MIT Department
Massachusetts Institute of Technology. Department of Civil and Environmental Engineering
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DOI of Published Version
https://doi.org/10.1104/pp.18.01185
