Disruption of RCI2A leads to over-accumulation of Na+ and increased salt sensitivity in Arabidopsis thaliana plants
Disruption of RCI2A leads to over-accumulation of Na+ and increased salt sensitivity in Arabidopsis thaliana plants
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DOI：
10.1007/s00425-005-0043-9
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发表时间：
2005-12-01
期刊：
影响因子：
4.3
通讯作者：
Takabe, T
中科院分区：
文献类型：
--
作者：
Mitsuya, S;Taniguchi, M;Takabe, T
调控Na+的吸收和积累对植物的耐盐性具有重要意义。缺失PMP 3基因的酵母pmp 3突变体在细胞中积累过量的Na+离子，并显示出增加的Na+敏感性。虽然PMP 3的功能尚未完全了解，但有人提出，PMP 3有助于限制Na+吸收，从而限制酵母的耐盐性。本文研究了拟南芥（Arabidopsis thaliana（L.）Heynh.）植物;从而表明RCI 2A在高等植物中的生理作用。鉴定了两个RCI 2A的T-DNA插入突变体。在正常条件下，rci 2a突变体的生长与野生型相当，但高盐处理导致Na+积累增加，根和芽的生长受到抑制。在高盐胁迫下，rci 2a突变体再生的未分化愈伤组织也比野生型积累了更多的Na+。此外，当用NaCl、NaNO 3、Na 2SO 4、KCl、KNO 3、K2 SO 4或LiCl处理野生型和rci 2a植株时，rci 2a突变体表现出比野生型更大的地上部生长减少。在氯化四甲基铵、CaCl 2、MgCl 2、甘露醇或山梨醇的处理下，野生型和rci 2a植物之间的生长减少是相当的。这些结果表明，RCI 2A在植物体内直接或间接地起着避免过量Na+和K+离子积累的作用，从而有助于植物的耐盐性。
For plant salt tolerance, it is important to regulate the uptake and accumulation of Na+ ions. The yeast pmp3 mutant which lacks PMP3 gene accumulates excess Na+ ions in the cell and shows increased Na+ sensitivity. Although the function of PMP3 is not fully understood, it is proposed that PMP3 contributes to the restriction of Na+ uptake and consequently salt tolerance in yeasts. In this paper, we have investigated whether the lack of RCI2A gene, homologous to PMP3 gene, causes a salt sensitive phenotype in Arabidopsis (Arabidopsis thaliana (L.) Heynh.) plants; and to thereby indicate the physiological role of RCI2A in higher plants. Two T-DNA insertional mutants of RCI2A were identified. Although the growth of rci2a mutants was comparable with that of wild type under normal conditions, high NaCl treatment caused increased accumulation of Na+ and more reduction of the growth of roots and shoots of rci2a mutants than that of wild type. Undifferentiated callus cultures regenerated from rci2a mutants also accumulated more Na+ than that from wild type under high NaCl treatment. Furthermore, when wild-type and rci2a plants were treated with NaCl, NaNO3, Na2SO4, KCl, KNO3, K2SO4 or LiCl, the rci2a mutants showed more reduction of shoot growth than wild type. Under treatments of tetramethylammonium chloride, CaCl2, MgCl2, mannitol or sorbitol, the growth reduction was comparable between wild-type and rci2a plants. These results suggested that RCI2A plays a role directly or indirectly for avoiding over-accumulation of excess Na+ and K+ ions in plants, and contributes to salt tolerance.