Overexpression of a <Emphasis Type="Italic">Panax ginseng</Emphasis> tonoplast aquaporin alters salt tolerance,drought tolerance and cold acclimation ability in transgenic <Emphasis Type="Italic">Arabidopsis</Emphasis> plants |
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Authors: | Yanhui Peng Wuling Lin Weiming Cai Rajeev Arora |
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Institution: | (1) Department of Horticulture, Iowa State University, Ames, IA 50011, USA;(2) Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China;(3) Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA 50011, USA |
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Abstract: | Water movement across cellular membranes is regulated largely by a family of water channel proteins called aquaporins (AQPs).
Since several abiotic stresses such as, drought, salinity and freezing, manifest themselves via altering water status of plant
cells and are linked by the fact that they all result in cellular dehydration, we overexpressed an AQP (tonoplast intrinsic
protein) from Panax ginseng, PgTIP1, in transgenic Arabidopsis
thaliana plants to test its role in plant’s response to drought, salinity and cold acclimation (induced freezing tolerance). Under
favorable conditions, PgTIP1 overexpression significantly increased plant growth as determined by the biomass production, and leaf and root morphology.
PgTIP1 overexpression had beneficial effect on salt-stress tolerance as indicated by superior growth status and seed germination
of transgenic plants under salt stress; shoots of salt-stressed transgenic plants also accumulated greater amounts of Na+ compared to wild-type plants. Whereas PgTIP1 overexpression diminished the water-deficit tolerance of plants grown in shallow (10 cm deep) pots, the transgenic plants
were significantly more tolerant to water stress when grown in 45 cm deep pots. The rationale for this contrasting response,
apparently, comes from the differences in the root morphology and leaf water channel activity (speed of dehydration/rehydration)
between the transgenic and wild-type plants. Plants overexpressed with PgTIP1 exhibited lower (relative to wild-type control) cold acclimation ability; however, this response was independent of cold-regulated
gene expression. Our results demonstrate a significant function of PgTIP1 in growth and development of plant cells, and suggest that the water movement across tonoplast (via AQP) represents a rate-limiting
factor for plant vigor under favorable growth conditions and also significantly affect responses of plant to drought, salt
and cold stresses. |
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Keywords: | Aquaporins Cold acclimation ability Drought tolerance Panax ginseng Tonoplast Intrinsic Protein (PgTIP1) Salt tolerance Transgenic Arabidopsis |
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