Over-expression of a barley aquaporin increased the shoot/root ratio and raised salt sensitivity in transgenic rice plants
2003
Katsuhara, M. | Koshio, K. | Shibasaka, M. | Hayashi, Y. | Hayakawa, T. | Kasamo, K.
Barley HvPIP2;1 is a plasma membrane aquaporin and its expression was down-regulated after salt stress in barley [Katsuhara et al.(2002) Plant Cell Physiol. 43: 885]. We produced and analyzed transgenic rice plants over-expressing barley HvPIP2;1 in the present study. Over expression of HvPIP2;1 increased (1) radial hydraulic conductivity of roots (Lpr) to 140%, and (2) the mass ratio of shoot to root up to 150%. In these transgenic rice plants under salt stress of 100 mM NaCl, growth reduction was greater than in non-transgenic plants. A decrease in shoot water content (from 79% to 61%) and reduction of root mass or shoot mass (both less than 40% of non-stressed plants) were observed in transgenic plants under salt stress for 2 weeks. These results indicated that over-expression of HvPIP2;1 makes rice plants sensitive to 100 mM NaCl. The possible involvement of aquaporins in salt tolerance is discussed.
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