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Short‐term control of maize cell and root water permeability through plasma membrane aquaporin isoforms
Author(s) -
HACHEZ CHARLES,
VESELOV DMITRY,
YE QING,
REINHARDT HAGEN,
KNIPFER THORSTEN,
FRICKE WIELAND,
CHAUMONT FRANÇOIS
Publication year - 2012
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.2011.02429.x
Subject(s) - aquaporin , hydraulic conductivity , chemistry , endodermis , biophysics , osmosis , polyethylene glycol , permeability (electromagnetism) , hydroponics , water transport , peg ratio , membrane , osmotic shock , microbiology and biotechnology , membrane permeability , botany , water flow , biochemistry , biology , soil water , gene , ecology , finance , environmental engineering , engineering , economics
Although it is widely accepted that aquaporins are involved in the regulation of root water uptake, the role of specific isoforms in this process is poorly understood. The mRNA expression and protein level of specific plasma membrane intrinsic proteins (PIPs) were analysed in Zea mays in relation to cell and root hydraulic conductivity. Plants were analysed during the day/night period, under different growth conditions (aeroponics/hydroponics) and in response to short‐term osmotic stress applied through polyethylene glycol (PEG). Higher protein levels of ZmPIP1;2, ZmPIP2;1/2;2, ZmPIP2;5 and ZmPIP2;6 during the day coincided with a higher water permeability of root cortex cells during the day compared with night period. Similarly, plants which were grown under aeroponic conditions and which developed a hypodermis (‘exodermis’) with Casparian bands, effectively forcing more water along a membranous uptake path across roots, showed increased levels of ZmPIP2;5 and ZmPIP1;2 in the rhizodermis and exodermis. When PEG was added to the root medium (2–8 h), expression of PIPs and cell water permeability in roots increased. These data support a role of specific PIP isoforms, in particular ZmPIP1;2 and ZmPIP2;5, in regulating root water uptake and cortex cell hydraulic conductivity in maize.