Exogenous application of gibberellic acid participates in up-regulation of lipid biosynthesis under salt stress in rice
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Alterations in membrane lipid composition lead to improved plant salt tolerance. Gibberellic acid (GA3) has also been widely reported to reduce growth inhibition induced by increased salinity. However, little is known about whether exogenous application of GA3 participates in up-regulation of lipid biosynthesis under salt stress. In this study, one of the major lipid biosynthesis genes in rice (Oryza sativa L. cv. Nipponbare), monogalactosyldiacylglycerol synthase (OsMGD) was found to be significantly up-regulated by GA3 treatment. Lipid analysis showed that after salt disturbance, the concentrations of all the measured lipids, including monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG) and phospholipid lipids + sulfoquinovosyl diacylglycerol (PL + SQDG) were decreased significantly. However, GA3 treatment prior to salt disturbance caused those lipids to remain at high levels, as well as preserving a high DGDG/MGDG ratio. The desaturation of DGDG (DBI) was also increased in GA3 pre-treatment plants as compared with no GA3 pre-treatment, primarily due to a decrease of 16:0 fatty acids and an increase of 18:3 fatty acids in DGDG. Plants pre-treated with GA3 prior to salt disturbance had higher dry weights than those without pre-treatment. The chlorophyll concentration was also higher in GA3 treated plants than in untreated plants under salt disturbance. Taken together, these results indicate that exogenous application of GA3 participates in up-regulation of chloroplast lipid biosynthesis under salt disturbance in rice.
KeywordsChloroplast membrane lipids Fatty acids Gibberellic acid Salt stress Rice
Double bond index
Thin Layer Chromatography
Fatty acyl methylester
Flame ionization detector
Light-harvesting chlorophyll complex II
This work was supported by the “Youth Elite Project” and “Young Faculty Study Abroad Program” of Northwest A&F University, the Youth Innovation Promotion Association of the Chinese Academy of Sciences [No. 2015389], the West Light Foundation of the Chinese Academy of Sciences, and the Project of Youth Science and Technology New Star in Shaanxi Province [2016KJXX-66].
LY planned the experiments and prepared the manuscript. XL and XW conducted the experiments, collected and analyzed the data and prepared a draft of the manuscript. XD and SW helped in drafting the manuscript and interpreting the results.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
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