fulltext.study @t Gmail

A T-DNA insertion mutant of AtHMA1 gene encoding a Cu transporting ATPase in Arabidopsis thaliana has a defect in the water–water cycle of photosynthesis

Paper ID Volume ID Publish Year Pages File Format Full-Text
30074 44458 2009 9 PDF Available
Title
A T-DNA insertion mutant of AtHMA1 gene encoding a Cu transporting ATPase in Arabidopsis thaliana has a defect in the water–water cycle of photosynthesis
Abstract

The water–water cycle is the electron flow through scavenging enzymes for the reactive species of oxygen in chloroplasts, and is proposed to play a role in alternative electron sink in photosynthesis. Here we showed that the water–water cycle is impaired in the T-DNA insertion mutant of AtHMA1 gene encoding a Cu transporting ATPase in chloroplasts. Chlorophyll fluorescence under steady state was not affected in hma1, indicating that photosynthetic electron transport under normal condition was not impaired. Under electron acceptor limited conditions, however, hma1 showed distinguished phenotype in chlorophyll fluorescence characteristics. The most severe phenotype of hma1 could be observed in high (0.1%) CO2 concentrations, indicating that hma1 has the defect other than photorespiration. The transient increase of chlorophyll fluorescence upon the cessation of the actinic light as well as the NPQ induction of chlorophyll fluorescence revealed that the two pathways of cyclic electron flow around PSI, NDH-pathway and FQR-pathway, are both intact in hma1. Based on the NPQ induction under 0% oxygen condition, we conclude that the water–water cycle is impaired in hma1, presumably due to the decreased level of Cu/Zn SOD in the mutant. Under high CO2 condition, hma1 exhibited slightly higher NPQ induction than wild type plants, while this increase of NPQ in hma1 was suppressed when hma1 was crossed with crr2 having a defect in NDH-mediated PSI cyclic electron flow. We propose that the water–water cycle and NDH-mediated pathways might be regulated compensationally with each other especially when photorespiration is suppressed.

Keywords
AtHMA1; Arabidopsis thaliana; Cu transporting ATPase in chloroplast; Cu/Zn SOD; Cyclic electron flow around PSI; Water–water cycle
First Page Preview
A T-DNA insertion mutant of AtHMA1 gene encoding a Cu transporting ATPase in Arabidopsis thaliana has a defect in the water–water cycle of photosynthesis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 94, Issue 3, 3 March 2009, Pages 205–213
Authors
, , , ,
Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us