Salt stress-induced dissociation from cells of a germin-like protein with Mn-SOD activity and an increase in its mRNA in a moss, Barbula unguiculata.

Masaru Nakata, Tadahiko Shiono, Yayoi Watanabe, Toshio Satoh

Department of Biological Science, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, 739-8526 Japan. bozikun@hiroshima-u.ac.jp

Plant & cell physiology 2002 Dec

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To estimate the physiological roles of a germin-like protein (BuGLP) with Mn-SOD activity isolated newly from a moss, Barbula unguiculata, BuGLP mRNA levels during cell growth and the effects of methyl viologen and salt stress were studied. BuGLP mRNA levels were at their peak during the exponential phase of growth and decreased thereafter, but SOD activity was held at the same level as that during the exponential phase. When methyl viologen was present as a generator of superoxide the amount of BuGLP transcripts decreased, but that of SOD activity of BuGLP bound to the cell wall was not affected. The addition of NaCl to the cells during the logarithmic phase increased both the BuGLP mRNA levels and total SOD activity of BuGLP, but decreased the SOD activity bound to the cell wall due to release of most of the SOD activity into the medium. On the other hand, the addition of NaCl to the cells during the stationary phase hardly affected BuGLP mRNA levels or SOD activity levels bound to the cell wall. These results suggest that the induction of BuGLP gene by salt stress is caused by dissociation of BuGLP protein from the cell wall into the medium in the cells during the logarithmic phase.

Citation

Masaru Nakata, Tadahiko Shiono, Yayoi Watanabe, Toshio Satoh. Salt stress-induced dissociation from cells of a germin-like protein with Mn-SOD activity and an increase in its mRNA in a moss, Barbula unguiculata. Plant & cell physiology. 2002 Dec;43(12):1568-74