Backgrounds

Acyl-coenzyme A (CoA) esters are important intermediates in lipid metabolism with regulatory properties. Acyl-CoA-binding proteins bind and transport acyl-CoAs to fulfill these functions. RICE ACYL-COA-BINDING PROTEIN6 (OsACBP6) is currently the only one peroxisome-localized plant ACBP that has been proposed to be involved in β-oxidation in transgenic Arabidopsis. The role of the peroxisomal ACBP (OsACBP6) in rice (Oryza sativa) was investigated.

Results

Here, we report on the function of OsACBP6 in rice. The osacbp6 mutant showed diminished growth with reduction in root meristem activity and leaf growth. Acyl-CoA profiling and lipidomic analysis revealed an increase in acyl-CoA content and a slight triacylglycerol accumulation caused by the loss of OsACBP6. Comparative transcriptomic analysis discerned the biological processes arising from the loss of OsACBP6. Reduced response to oxidative stress was represented by a decline in gene expression of a group of peroxidases and peroxidase activities. An elevation in hydrogen peroxide was observed in both roots and shoots/leaves of osacbp6. Taken together, loss of OsACBP6 not only resulted in a disruption of the acyl-CoA homeostasis but also peroxidase-dependent reactive oxygen species (ROS) homeostasis. In contrast, osacbp6-complemented transgenic rice displayed similar phenotype to the wild type rice, supporting a role for OsACBP6 in the maintenance of the acyl-CoA pool and ROS homeostasis. Furthermore, quantification of plant hormones supported the findings observed in the transcriptome and an increase in jasmonic acid level occurred in osacbp6.

Conclusions

In summary, OsACBP6 appears to be required for the efficient utilization of acyl-CoAs. Disruption of OsACBP6 compromises growth and led to provoked defense response, suggesting a correlation of enhanced acyl-CoAs content with defense responses.

中文翻译：

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水稻酰基辅酶A结合蛋白6影响水稻酰基辅酶A稳态和生长

背景资料

酰基辅酶A（CoA）酯是脂质代谢中具有调控特性的重要中间体。酰基辅酶A结合蛋白结合并转运酰基辅酶A以实现这些功能。水稻酰基-COA结合蛋白6（OsACBP6）是目前提出的唯一一种过氧化物酶体定位的植物ACBP，其参与转基因拟南芥中的β-氧化。研究了过氧化物酶体ACBP（OsACBP6）在水稻（Oryza sativa）中的作用。

结果

在这里，我们报告OsACBP6在水稻中的功能。所述osacbp6突变体显示与还原根分生组织活性和叶生长减弱的生长。酰基辅酶A分析和脂质组分析显示，由于OsACBP6的缺失，酰基辅酶A含量增加，三酰基甘油略有积累。比较转录组分析辨别了OsACBP6丢失引起的生物学过程。对氧化应激反应的降低以一组过氧化物酶和过氧化物酶活性的基因表达下降为代表。在osacbp6的根和芽/叶中都观察到过氧化氢的升高。两者合计，OsACBP6的损失不仅导致酰基辅酶A动态平衡的破坏，而且导致过氧化物酶依赖性活性氧（ROS）动态平衡的破坏。相反，osacbp6互补的转基因水稻表现出与野生型水稻相似的表型，支持OsACBP6在维持酰基辅酶A库和ROS稳态中的作用。此外，植物激素的定量支持在转录组中观察到的发现，并且osacbp6中茉莉酸水平增加。

结论

总之，OsACBP6似乎是有效利用酰基辅酶A所必需的。OsACBP6的破坏会损害生长并导致激起的防御反应，表明酰基辅酶A含量增加与防御反应相关。