Skip Navigation



Plant and Cell Physiology Advance Access published online on July 14, 2005
Plant and Cell Physiology, doi:10.1093/pcp/pci164
This Article
Right arrow Advance Access manuscript (PDF)
Right arrow All Versions of this Article:
46/9/1515    most recent
pci164v2
pci164v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Google Scholar
Right arrow Articles by Nanasato, Y.
Right arrow Articles by Yokota, A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Nanasato, Y.
Right arrow Articles by Yokota, A.
Agricola
Right arrow Articles by Nanasato, Y.
Right arrow Articles by Yokota, A.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

Plant and Cell Physiology 2005 © The Japanese Society of Plant Physiologists (JSPP); all rights reserved.
Received March 15, 2005
Accepted July 7, 2005

Regular paper

Co-Expression of Cytochrome b561 and Ascorbate Oxidase in Leaves of Wild Watermelon under Drought and High Light Conditions

Yoshihiko Nanasato 1, Kinya Akashi 1, and Akiho Yokota 1*

1 Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan

* To whom correspondence should be addressed.
Akiho Yokota, E-mail: yokota{at}bs.naist.jp


  Abstract

Despite carrying out C3 photosynthesis, wild watermelon (Citrullus lanatus L.) exhibits exceeding tolerance to severe drought at high light intensities. However, the mechanism(s) by which this plant protects itself from photodamage has yet to be elucidated. In this study, we characterized wild watermelon cytochrome b561 (cyt b561), which potentially mediates regeneration of apoplastic ascorbate by transferring electrons from cytosolic ascorbate across the plasma membrane. Two cDNA species for wild watermelon cyt b561, designated CLb561A and CLb561B, respectively, were isolated. Levels of both CLb561A mRNA and protein were significantly elevated in the leaves during drought at a light intensity of 700 µmol photons m-2 s-1. The transcript of CLb561B was detected to a much lesser extent, but no CLb561B protein was produced under any condition used in this study. A transient expression assay with the CLb561A::green fluorescent protein fusion construct showed clear fluorescence on the plasma membrane of onion epidermal cells. The CLb561A protein was enriched in the plasma membrane fraction in leaves of transgenic tobacco expressing CLb561A. Moreover, the high activity of apoplastic ascorbate oxidase (AO), which was able to dispose of cyt b561-transferred reducing equivalents, increased in leaves of wild watermelon grown at high light intensity, but not lower light intensities. Taken together, these observations suggest the occurrence of a novel pathway for excess light energy dissipation in wild watermelon leaves, where excessive energy absorbed by chloroplasts can be transported to and dissipated safely in the apoplasts through the cooperative action of cyt b561 and AO.

Keywords: Ascorbate oxidase; Cytochrome b561; Drought tolerance; Excess energy dissipation; Oxidative stress; Wild watermelon (Citrullus lanatus L.).
Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?


This article has been cited by other articles:


Home page
 Plant Physiol.Home page
V. Preger, N. Tango, C. Marchand, S. D. Lemaire, D. Carbonera, M. Di Valentin, A. Costa, P. Pupillo, and P. Trost
Auxin-Responsive Genes AIR12 Code for a New Family of Plasma Membrane b-Type Cytochromes Specific to Flowering Plants
Plant Physiology, June 1, 2009; 150(2): 606 - 620.
[Abstract] [Full Text] [PDF]

Home page
 Plant Cell PhysiolHome page
K. Yoshimura, A. Masuda, M. Kuwano, A. Yokota, and K. Akashi
Programmed Proteome Response for Drought Avoidance/Tolerance in the Root of a C3 Xerophyte (Wild Watermelon) Under Water Deficits
Plant Cell Physiol., February 1, 2008; 49(2): 226 - 241.
[Abstract] [Full Text] [PDF]

Home page
 Plant Physiol.Home page
C. Pignocchi, G. Kiddle, I. Hernandez, S. J. Foster, A. Asensi, T. Taybi, J. Barnes, and C. H. Foyer
Ascorbate Oxidase-Dependent Changes in the Redox State of the Apoplast Modulate Gene Transcript Accumulation Leading to Modified Hormone Signaling and Orchestration of Defense Processes in Tobacco
Plant Physiology, June 1, 2006; 141(2): 423 - 435.
[Abstract] [Full Text] [PDF]


Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.