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One of most highly expressed aquaporin gene in the leaves and roots of rice, highly responsible to environmental stresses.[1]

Annotated Information


According to the nomenclature of PIP genes in maize, this gene has been designated as OsPIP1-1. PIP genes are the protein encoding genes of plasma membrane intrinsic proteins (PIPs) -- a subfamily of aquaporins that enable fast and controlled translocation of water across the membrane. There are recently 10 designated PIP genes in the gnome of rice, they are classified into two groups, that is OsPIP1-1 to OsPIP1-3 and OsPIP2-1 to OsPIP2-7, based on the similarity of their amino acid sequences.[2] The ubiquitously expression of OsPIP1-1 gene in rice leaves and roots indicates its important physiological role.


Experiments show that when transiently expressed as EGFP-OsPIP1 in rice cell protoplasts, it is mainly distributed in cytoplasm, While co-expressing with EGFP-OsPIP1 make it re -translocate to plasma membrane. This observation is further confirmed by the water permeability measuring experiment.[1]

Seed germination

Transgenic rice seeds with overexpressed OsPIP1 exhibit a significant higher germination rate than the control, this is consistent with the higher α-amylase activity in transgenic seeds.[1]

Salt tolerance

Experiments show that when not overexpressed at high level,OsPIP1 will efficiently promote salt resistance in rice, but when has high OsPIP1 expression level, rice will become more sensitive to high salt environment than control.[1]

Seed yield

Transgenic rice plants with various OsPIP1 express level show that, appropriate low level of overexpressed OsPIP1 will increase seed yield, while high level of OsPIP1 expression will decrease seed yield, and extremely high expression will even make rice sterile.[1]

Structured Information


Aquaporin family occur in greatest numbers and with the greatest diversity in plants. Angiosperm species have ~30 different aquaporins grouped into four subfamilies: plasma membrane intrinsic proteins (PIPs), tonoplast intrinsic proteins (TIPs), nodulin 26-like intrinsic proteins (NIPs), and small, basic intrinsic proteins (SIPs). An EST library of the moss Physcomitrella patens reveals that its aquaporins fall into the same subfamilies, indicating that the main radiation of plant aquaporins was already established when land plant evolution began.[3]

The partial identification of Physcomitrella aquaporins demonstrates that the diversification into PIP, TIP, NIP and SIP subfamilies, as well as the differentiation into PIP1 and PIP2 classes, pre-dates the divergence of bryophytes and tracheophytes, whereas the differentiation of α-, γ- and δ-TIPs must have occurred during the evolution of tracheophytes. Identification of aquaporins in charophytes should elucidate to what degree the plant aquaporins had diversified before the algal ancestors invaded the land.[3]

"diversification of aquaporins (from reference [3])."

Labs working on this gene

Graduate School of Bioresource Sciences, Akita Prefectural University, Shimoshinjo, Akita 010-0195, Japan

Institute of Plant Science and Resources, Okayama University, Kuashiki 710-0046, Japan

College of Life Science, Northeast Agricultural University, Harbin 150030, China

Peking-Yale Joint Research Center for Plant Molecular Genetics and AgroBiotechnology, National Laboratory for Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing 100871, China


  1. 1.0 1.1 1.2 1.3 1.4 Liu C, Fukumoto T, Matsumoto T, Gena P, Frascaria D, Kaneko T, Katsuhara M, et al. (2013) Aquaporin OsPIP1;1 promotes rice salt resistance and seed germination. Plant Physiol Biochem.63:151-8.
  2. Guo L, Wang ZY, Lin H, Cui WE, et al.(2006) Expression and functional analysis of the rice plasma-membrane intrinsic protein gene family. Cell Res. 16(3):277-86.
  3. 3.0 3.1 3.2 Borstlap AC. (2002) Early diversification of plant aquaporins. Trends Plant Sci. 7(12):529-30.

Structured Information