Monsanto Company, Davis, California 95616, USA.
Plant Physiol. 2011 Mar;155(3):1146-57. doi: 10.1104/pp.110.167676. Epub 2011 Jan 18.
Maize (Zea mays) oil has high value but is only about 4% of the grain by weight. To increase kernel oil content, fungal diacylglycerol acyltransferase2 (DGAT2) genes from Umbelopsis (formerly Mortierella) ramanniana and Neurospora crassa were introduced into maize using an embryo-enhanced promoter. The protein encoded by the N. crassa gene was longer than that of U. ramanniana. It included 353 amino acids that aligned to the U. ramanniana DGAT2A protein and a 243-amino acid sequence at the amino terminus that was unique to the N. crassa DGAT2 protein. Two forms of N. crassa DGAT2 were tested: the predicted full-length protein (L-NcDGAT2) and a shorter form (S-NcDGAT2) that encoded just the sequences that share homology with the U. ramanniana protein. Expression of all three transgenes in maize resulted in small but statistically significant increases in kernel oil. S-NcDGAT2 had the biggest impact on kernel oil, with a 26% (relative) increase in oil in kernels of the best events (inbred). Increases in kernel oil were also obtained in both conventional and high-oil hybrids, and grain yield was not affected by expression of these fungal DGAT2 transgenes.
玉米油具有很高的价值，但在重量上仅占谷物的 4%左右。为了提高玉米的含油量，利用胚乳增强启动子将来自 Umbellopsis（原名 Mortierella）ramanniana 和 Neurospora crassa 的真菌二酰基甘油酰基转移酶 2（DGAT2）基因导入玉米中。N. crassa 基因编码的蛋白质比 U. ramanniana 的长。它包括与 U. ramanniana DGAT2A 蛋白对齐的 353 个氨基酸和 N. crassa DGAT2 蛋白特有的 243 个氨基酸序列。测试了两种形式的 N. crassa DGAT2：预测的全长蛋白（L-NcDGAT2）和较短的形式（S-NcDGAT2），仅编码与 U. ramanniana 蛋白具有同源性的序列。在玉米中表达所有三种转基因都导致了 kernels 中油含量的微小但具有统计学意义的增加。S-NcDGAT2 对 kernels 油的影响最大，最佳事件（自交系）的油含量增加了 26%（相对）。在传统和高油杂交种中也获得了 kernels 油的增加，并且这些真菌 DGAT2 转基因的表达并没有影响谷物产量。
