Aquaporin OsPIP1;1 promotes rice salt resistance and seed germination

Chengwei Liua, Tatsuya Fukumotoa, Tadashi Matsumotoa, Patrizia Genab, Daniele Frascariab, Tomoyuki Kanekoc, Maki Katsuharac, Shihua Zhongd, Xiaoli Sune, Yanming Zhue, Ikuko Iwasakia, Xiaodong Dingd, Giuseppe Calamitab, Yoshichika Kitagawaa

Plant Physiology and Biochemistry, Volume 63, February 2013, Pages 151–158

Abstract

OsPIP1;1 is one of the most abundant aquaporins in rice leaves and roots and is highly responsible to environmental stresses. However, its biochemical and physiological functions are still largely unknown. The oocyte assay data showed OsPIP1;1 had lower water channel activity in contrast to OsPIP2;1. EGFP and immunoelectron microscopy studies revealed OsPIP1;1 was predominantly localized in not only plasma membrane but also in some ER-like intracellular compartments in the cells. OsPIP1;1 exhibited low water channel activity in Xenopusoocytes but coexpression of OsPIP2;1 significantly enhanced its water permeability. Stop-flow assay indicated that 10His-OsPIP1;1-reconstituted proteoliposomes had significantly higher water permeability than the control liposomes. Overexpression of OsPIP1;1 greatly altered many physiological features of transgenic plants in a dosage-dependent manner. Moderate expression of OsPIP1;1 increased rice seed yield, salt resistance, root hydraulic conductivity, and seed germination rate. This work suggests OsPIP1;1 functions as an active water channel and plays important physiological roles.