甘蓝型油菜皖油12种子中含芥酸甘油三酯的空间分布

Distribution of triacylglycerol containing erucic acid in seed of Brassica napus cv Wanyou 12

油菜是重要工业原料芥酸(C22:1)的来源作物,从空间分布的角度解析油菜种子中芥酸积累的机制,为高芥酸油菜育种提供新方法。利用基质辅助激光解吸电离-质谱成像技术,以芥酸含量为26%的甘蓝型油菜皖油12为材料,分析甘油三酯(triacylglycerol, TAG)在种子的外子叶、内子叶及胚轴中的空间分布。结果表明C58、C60和C62类型的TAG主要富集在种子的子叶(包括外子叶和内子叶),而C原子数小于58的TAG则主要富集在胚轴中(除TAG-54:2、TAG-54:3和TAG-56:2~TAG-56:5无分布差异)。分析开花后38 d种子外子叶、内子叶及胚轴中基因FAE1(fatty acid elongase 1)的表达量,发现FAE1在外子叶和内子叶中的表达量分别是胚轴中的约10倍和20倍。结果表明,种子不同部位FAE1表达量的差异是影响含芥酸TAG在种子中分布的主要因素。

Nowadays, erucic acid(C22:1) has been increasingly used as the source of industrial material. To better understand the distribution of triacylglycerol(TAG) in high-erucic acid rapeseed, we used matrix-assisted laser desorption/ionization-mass spectrometry imaging(MALDI-MSI) technology to employ spatial distribution of TAG in Brassica napus L. cv Wanyou 12(WY12), whcih containing 26% erucic acid. Results indicated that TAGC58, C60, and C62 were enriched in the outer cotyledon(OC) and inner cotyledon(IC). In contrast, TAG species with less than 58 carbons preferentially accumulated in the embryonic axis(EA), except that TAG-54:2, TAG-54:3 and TAG-56:2 to TAG-56:5 displayed no heterogeneity in different seed tissues. The FATTY ACID ELONGASE 1(FAE1) expression level of 38 DAF(days after flowering) seed showed that FAE1 had 10-and 20-fold higher expression in OC and IC than that in EA respectively. The results suggested that the different expression of FAE1 in different seed tissues was the main factor affecting the spatial distribution of TAG containing C22:1 in the seed of WY12.