Protection of the photosynthetic apparatus against dehydration stress in the resurrection plant Craterostigma pumilum.
The group of homoiochlorophyllous resurrection plants evolved the unique capability to survive severe drought stress without dismantling the photosynthetic machinery. This implies that they developed efficient strategies to protect the leaves from reactive oxygen species (ROS) generated by photosynthetic side reactions. These strategies, however, are poorly understood. Here, we performed a detailed study of the photosynthetic machinery in the homoiochlorophyllous resurrection plant Craterostigma pumilum during dehydration and upon recovery from desiccation. During dehydration and rehydration, C. pumilum deactivates and activates partial components of the photosynthetic machinery in a specific order, allowing for coordinated shutdown and subsequent reinstatement of photosynthesis. Early responses to dehydration are the closure of stomata and activation of electron transfer to oxygen accompanied by inactivation of the cytochrome b6 f complex leading to attenuation of the photosynthetic linear electron flux (LEF). The decline in LEF is paralleled by a gradual increase in cyclic electron transport to maintain ATP production. At low water contents, inactivation and supramolecular reorganization of photosystem II becomes apparent, accompanied by functional detachment of light-harvesting complexes and interrupted access to plastoquinone. This well-ordered sequence of alterations in the photosynthetic thylakoid membranes helps prepare the plant for the desiccated state and minimize ROS production.
Institute of Biological Chemistry, Washington State University, Pullman, WA, 99164-6340, USA.
Ahmad
A
Zia
School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, WA, 99164-4236, USA.
Berkley J
BJ
Walker
Institute of Biological Chemistry, Washington State University, Pullman, WA, 99164-6340, USA.
Hui Min Olivia
HM
Oung
Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, 76100, Israel.
Dana
D
Charuvi
Plant Biochemistry, Heinrich-Heine University Düsseldorf, Düsseldorf 40225, Germany.
Peter
P
Jahns
School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, WA, 99164-4236, USA.
Asaph B
AB
Cousins
Department of Molecular and Cell Biology, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa.
Jill M
JM
Farrant
Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, 76100, Israel.
Ziv
Z
Reich
Institute of Biological Chemistry, Washington State University, Pullman, WA, 99164-6340, USA. kirchhh@wsu.edu.
Helmut
H
Kirchhoff
D002245:Carbon Dioxide / Q000378:metabolism; D032181:Craterostigma / Q000502:physiology*; D045346:Cytochrome b6f Complex / Q000378:metabolism; D003681:Dehydration; D004579:Electron Transport; D010788:Photosynthesis / Q000502:physiology*; D045332:Photosystem II Protein Complex / Q000378:metabolism; D054046:Plant Stomata / Q000502:physiology; D020524:Thylakoids / Q000378:metabolism
D045332:Photosystem II Protein Complex; D002245:Carbon Dioxide; D045346:Cytochrome b6f Complex
drought tolerance; photosynthesis; resurrection plants; thylakoid membrane