Lipid catabolism in germinating seeds provides energy and substrates for initial seedling growth,but how this process is regulated is not well understood.Here,we show that an AT-hook motif-containing nuclear localized...Lipid catabolism in germinating seeds provides energy and substrates for initial seedling growth,but how this process is regulated is not well understood.Here,we show that an AT-hook motif-containing nuclear localized(AHL)protein regulates lipid mobilization and fatty acid p-oxidation during seed germination and seedling establishment.AHL4 was identified to directly interact with the lipid mediator phosphatidic acid(PA).Knockout(KO)of AHL4 enhanced,but overexpression(OE)of AHL4 attenuated,triacylglycerol(TAG)degradation and seedling growth.Normal seedling growth of the OE lines was restored by sucrose supplementation to the growth medium.AHL4-OE seedlings displayed decreased expression of genes involved in TAG hydrolysis and fatty acid oxidation,whereas the opposite was observed in AHL4-KOs.These genes contained AHL4-binding cis elements,and AHL4 was shown to bind to the promoter regions of genes encoding the TAG lipases SDP1 and DALL5 and acyl-thioesterase KAT5.These AHL4-DNA interactions were suppressed by PA species that bound to AHL4.These results indicate that AHL4 suppresses lipid catabolism by repressing the expression of specific genes involved in TAG hydrolysis and fatty acid oxidation,and that PA relieves AHL4-mediated suppression and promotes TAG degradation.Thus,AHL4 and PA together regulate lipid degradation during seed germination and seedling establishment.展开更多
基金The work is supported by grants from the National Key Research and Development Program of China(2017YFE0104800)National Natural Science Foundation of China(31801029)+1 种基金the U.S.Department of Energy(DESC0001295)the Agriculture and Food Research Initiative(AFRI)(award no.2016-67013-24429,project accession number 1007600)from the USDA National Institute of Food and Agriculture,and the International Postdoctoral Exchange Fellowship Program 2016 of the Office of China Postdoctoral Council(20160034).
文摘Lipid catabolism in germinating seeds provides energy and substrates for initial seedling growth,but how this process is regulated is not well understood.Here,we show that an AT-hook motif-containing nuclear localized(AHL)protein regulates lipid mobilization and fatty acid p-oxidation during seed germination and seedling establishment.AHL4 was identified to directly interact with the lipid mediator phosphatidic acid(PA).Knockout(KO)of AHL4 enhanced,but overexpression(OE)of AHL4 attenuated,triacylglycerol(TAG)degradation and seedling growth.Normal seedling growth of the OE lines was restored by sucrose supplementation to the growth medium.AHL4-OE seedlings displayed decreased expression of genes involved in TAG hydrolysis and fatty acid oxidation,whereas the opposite was observed in AHL4-KOs.These genes contained AHL4-binding cis elements,and AHL4 was shown to bind to the promoter regions of genes encoding the TAG lipases SDP1 and DALL5 and acyl-thioesterase KAT5.These AHL4-DNA interactions were suppressed by PA species that bound to AHL4.These results indicate that AHL4 suppresses lipid catabolism by repressing the expression of specific genes involved in TAG hydrolysis and fatty acid oxidation,and that PA relieves AHL4-mediated suppression and promotes TAG degradation.Thus,AHL4 and PA together regulate lipid degradation during seed germination and seedling establishment.
