Salinity induces membrane structure and lipid changes in maize mesophyll and bundle sheath chloroplasts
The membranes of Zea mays (maize) mesophyll cell (MC) chloroplasts are more vulnerable to salinity stress than are those of bundle sheath cell (BSC) chloroplasts. To clarify the mechanism underlying this difference in salt sensitivity, we monitored changes in the glycerolipid and fatty acid composit...
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| Published in | Physiologia plantarum Vol. 157; no. 1; pp. 13 - 23 |
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| Main Authors | , , , |
| Format | Journal Article |
| Language | English |
| Published |
Oxford, UK
Blackwell Publishing Ltd
01.05.2016
Wiley Subscription Services, Inc |
| Subjects | |
| Online Access | Get full text |
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| Summary: | The membranes of Zea mays (maize) mesophyll cell (MC) chloroplasts are more vulnerable to salinity stress than are those of bundle sheath cell (BSC) chloroplasts. To clarify the mechanism underlying this difference in salt sensitivity, we monitored changes in the glycerolipid and fatty acid compositions of both types of chloroplast upon exposure to salinity stress. The monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG) contents were higher in MC chloroplasts than in BSC chloroplasts, in both the presence and absence of salt treatment. Under salt conditions, the MGDG level in MC chloroplasts was significantly lower than under normal conditions, while it was unchanged in BSC chloroplasts. In both types of chloroplast, the contents of DGDG, phosphatidylglycerol and phosphatidylinositol remained at the same levels in control and salt‐treated plants, whereas sulfoquinovosyldiacylglycerol and phosphatidylcholine were significantly lower and higher, respectively, upon salt treatment. In addition, the fatty acid composition and double bond index of individual lipid classes were changed by salt treatment in both BSC and MC chloroplasts, although these factors had no effect on glycerolipid content. These findings suggest that the difference in salt sensitivity of MC and BSC chloroplast membranes is related to differences in MGDG responses to salinity. Thus, we propose that the low MGDG content and the low sensitivity of MGDG to salinity in BSC chloroplasts render them more tolerant than MC chloroplasts to salinity stress. |
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| Bibliography: | ark:/67375/WNG-QR41PRDJ-1 Table S1. Effect of salinity on the glycerolipid composition (mol%) in MC and BSC chloroplasts of maize. Values represent means ± se of three or more independent experiments. For each treatment, means in rows followed by different letters are significantly different at P < 0.05 (anova with Scheffe's test).Figure S1. Glycerolipid contents in BSC chloroplasts of maize control plants isolated by the mechanical method according to Omoto et al. (). The content of each lipid species was quantified against a nonadecanoic acid methyl ester (internal standard) and is expressed as molar content per chloroplast dry weight.Figure S2. Effect of salinity on lipoxygenase activity in MC and BSC chloroplasts of maize. Values represent mean ± se of three or more independent experiments. Different letters indicate statistical difference at P < 0.05 (anova with Scheffe's test). Lipoxygenase activity was measured according to the method of Sharma et al. () with minor modification. The reaction mixture contained 0.03% Tween-20, 0.2 M phosphate buffer (pH 6.5), 0.8 mM linoleic acid and the chloroplast suspension, and was monitored with a spectrophotometer (JASCO Ubest-50; Japan Spectroscopic Co., Tokyo, Japan) as an increase in the absorbance at 234 nm, which reflects the formation of hydroperoxy linoleic acid. The activity was calculated by using extinction coefficient of 25 mM−1 cm−1 (Kulkarni and Cook ). istex:8CB802386F2858D1FC6F610229C18E203B446137 ArticleID:PPL12404 JSPS KAKENHI - No. 26292011; No. 26660015 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
| ISSN: | 0031-9317 1399-3054 |
| DOI: | 10.1111/ppl.12404 |