National Agri-Food Biotechnology Institute (NABI), Sector-81, SAS Nagar, Mohali, 140306, India.
Department of Biotechnology, Panjab University, Sector-25, Chandigarh, 160014, India.
Plant Cell Rep. 2021 Jul;40(7):1215-1228. doi: 10.1007/s00299-021-02714-4. Epub 2021 May 24.
Among the 113 lipases present in rice genome, bran and endosperm-specific lipases were identified and lipase activity for one of the selected lipase gene is demonstrated in yeast. Rice bran is nutritionally superior than endosperm as it has major reservoirs of various minerals, vitamins, essential mineral oils and other bioactive compounds, however it is often under-utilized as a food product due to bran instability after milling. Various hydrolytic enzymes, such as lipases, present in bran causes degradation of the lipids present and are responsible for the bran instability. Here, in this study, we have systematically analyzed the 113 lipase genes present in rice genome, and identified 21 seed-specific lipases. By analyzing the expression of these genes in different seed tissues during seed development, we have identified three bran-specific and three endosperm-specific lipases, and one lipase which expresses in both bran and endosperm tissues. Further analysis of these genes during seed maturation and seed germination revealed that their expression increases during seed maturation and decreases during seed germination. Finally, we have shown the lipase activity for one of the selected genes, LOC_Os05g30900, in heterologous system yeast. The bran-specific lipases identified in this study would be very valuable for engineering designer rice varieties having increased bran stability in post-milling.
在水稻基因组中的 113 种脂肪酶中，鉴定了糠层和胚乳特异性脂肪酶，并在酵母中证明了所选脂肪酶基因之一的脂肪酶活性。与胚乳相比，米糠在营养上更优越，因为它含有各种矿物质、维生素、必需矿物油和其他生物活性化合物的主要储备，但由于碾米后糠层不稳定，通常未得到充分利用作为食品。糠层中存在的各种水解酶，如脂肪酶，会导致脂质降解，从而导致糠层不稳定。在这项研究中，我们系统地分析了水稻基因组中存在的 113 种脂肪酶基因，并鉴定了 21 种种子特异性脂肪酶。通过分析这些基因在种子发育过程中不同种子组织中的表达，我们鉴定了 3 种糠层特异性和 3 种胚乳特异性脂肪酶，以及 1 种在糠层和胚乳组织中表达的脂肪酶。对这些基因在种子成熟和种子萌发过程中的进一步分析表明，它们的表达在种子成熟过程中增加，在种子萌发过程中减少。最后，我们在异源系统酵母中展示了所选基因之一 LOC_Os05g30900 的脂肪酶活性。本研究中鉴定的糠层特异性脂肪酶对于工程设计具有增加碾米后糠层稳定性的水稻品种非常有价值。
