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Relative abundance of Δ 5 ‐sterols in plasma membrane lipids of root‐tip cells correlates with aluminum tolerance of rice
Author(s) -
Hossain Khan M. Shahadat,
Tawaraya Keitarou,
Sekimoto Hiroshi,
Koyama Hiroyuki,
Kobayashi Yuriko,
Murayama Tetsuya,
Chuba Masaru,
Kambayashi Mihoko,
Shiono Yoshihito,
Uemura Matsuo,
Ishikawa Satoru,
Wagatsuma Tadao
Publication year - 2009
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.2008.01175.x
Subject(s) - cultivar , sterol , biology , japonica , botany , horticulture , biochemistry , cholesterol
We investigated variations in aluminum (Al) tolerance among rice plants, using ancestor cultivars from the family line of the Al‐tolerant and widely cultivated Japonica cultivar, Sasanishiki. The cultivar Rikuu‐20 was Al sensitive, whereas a closely related cultivar that is a descendant of Rikuu‐20, Rikuu‐132, was Al tolerant. These two cultivars were compared to determine mechanisms underlying variations in Al tolerance. The sensitive cultivar Rikuu‐20 showed increased permeability of the plasma membrane (PM) and greater Al uptake within 1 h of Al treatment. This could not be explained by organic acid release. Lipid composition of the PM differed between these cultivars, and may account for the difference in Al tolerance. The tolerant cultivar Rikuu‐132 had a lower ratio of phospholipids to Δ 5 ‐sterols than the sensitive cultivar Rikuu‐20, suggesting that the PM of Rikuu‐132 is less negatively charged and less permeabilized than that of Rikuu‐20. We used inhibitors of Δ 5 ‐sterol synthesis to alter the ratio of phospholipids to Δ 5 ‐sterols in both cultivars. These inhibitors reduced Al tolerance in Rikuu‐132 and its Al‐tolerant ancestor cultivars Kamenoo and Kyoku. In addition, Rikuu‐132 showed a similar level of Al sensitivity when the ratio of phospholipids to Δ 5 ‐sterols was increased to match that of Rikuu‐20 after treatment with uniconazole‐P, an inhibitor of obtusifoliol‐14α‐demethylase. These results indicate that PM lipid composition is a factor underlying variations in Al tolerance among rice cultivars.