Joint Sino-German-Project: Functional analysis and mutagenesis of GDSL genes for breeding oilseed rape (B. napus) with higher oil content GDSL

在中国和德国，油菜籽都是重要的大田作物，也是植物食用油的主要来源。2013年4月3日至6日，首届中德油菜籽遗传与生物技术研讨会在杭州举行。在研讨会上，浙江大学的蒋丽希教授、基尔大学的Christian Jung教授和他们的同事讨论了系统克隆和分析拟南芥种子脂肪酸减少器(Sar)基因和鉴定甘蓝型油菜BnSFAR基因敲除突变体的合作。为了提高种子含油量，人们在促进油脂生物合成效率方面做了很多努力，但对油脂积累过程中油脂分解的阻断作用却关注较少。SFAR被定义为在种子中表达的GDSL-型脂肪酶基因。它们能分解三酰甘油，减少种子脂肪的积累。江斯教授团队的初步研究指出，在拟南芥中约有25个sfr。5个基因(SFAR1-SFAR5)的缺失导致种子中脂肪酸(FA)含量显著增加。此外，多个SIFR基因座的功能丧失对促进种子产油具有加性效应。由于拟南芥和油菜(Brassica Napus)同属十字花科植物，它们在控制代谢途径方面具有相同的调控机制。因此，我们推测，BnSFAR的中断增加了甘蓝型油菜的种子油产量，而聚合Bnsar突变体可能导致更高的种子油含量。中国农业大学的Jungs教授团队已经建立了一个油菜突变群体，该群体可以很容易地通过TILLING(靶向诱导基因组局部损伤)方案进行筛选。该联合项目旨在(1)系统克隆拟南芥sfar基因并了解其功能和调控；(2)鉴定甘蓝型油菜(B.napus)中5个sar基因(AtSFAR1-AtSFAR5)的同源基因并筛选击倒突变体；(3)研究Bnsar突变对油菜种子含油量的影响和甘蓝型油菜(B.napus)金字塔bnsar突变。

Rapeseed is an important field crop and the major source of plant edible oil in both China and Germany. The first Sino-German Workshop on Genetics and Biotechnology of Rapeseed took place in Hangzhou on April 3-6, 2013. During the workshop Prof. Lixi Jiang of Zhejiang University (ZJU), Prof. Christian Jung of Christian-Albrechts-University Kiel (CAU) and their coworkers discussed the cooperation to systemically clone and analyze Seed Fatty Acid Reducer (SFAR) genes in Arabidopsis and identify BnSFAR knock-out mutants in Brassica napus. To increase seed oil content, many efforts have been made on the promotion of lipid biosynthesis efficiency, but little attention has been paid on the blocking of lipid decomposition in the process of oil accumulation. SFARs are defined as GDSL-type lipase genes that are expressed in seeds. They hydrolyze triacylglycerol and reduce the accumulation of seed lipids. Preliminary studies from Prof. Jiangs group pointed at ca. 25 SFARs in Arabidopsis. The disruption of 5 genes (SFAR1 - SFAR5) resulted in significant increases of fatty acids (FA) in seeds. Moreover, the loss of function at multiple sfar loci had an additive effect on promoting seed oil production. Since Arabidopsis thaliana and oilseed rape (Brassica napus) belong to the Brassicaceae family, it is expected that they share the same regulatory mechanisms to control metabolic pathways. Therefore we reason that disruption of a BnSFAR increases seed oil production in B. napus, and pyramiding Bnsfar mutants could lead to an even higher seed oil content. Prof. Jungs group at CAU has established a rapeseed mutant population which can be easily screened by a TILLING (targeting induced local lesions in genomes) protocol. The proposed joint project aims to (1) systematically clone putative Arabidopsis SFARs and to understand their functions and regulation, (2) to identify the orthologs of 5 SFAR genes (AtSFAR1 - AtSFAR5) in B. napus and to select knock down mutants, and (3) to characterize the effect of Bnsfar mutations on seed oil content and pyramide bnsfar mutations in oilseed rape (B. napus).