Key message

MANNANASE7 gene in Brassica napus L. encodes a hemicellulose which located at cell wall or extracellular space and dehiscence-resistance can be manipulated by altering the expression of MANNANASE7.

Abstract

Silique dehiscence is an important physiological process in plant reproductive development, but causes heavy yield loss in crops. The lack of dehiscence-resistant germplasm limits the application of mechanized harvesting and greatly restricts the rapeseed (Brassica napus L.) production. Hemicellulases, together with cellulases and pectinases, play important roles in fruit development and maturation. The hemicellulase gene MANNANASE7 (MAN7) was previously shown to be involved in the development and dehiscence of Arabidopsis (Arabidopsis thaliana) siliques. Here, we cloned BnaA07g12590D (BnMAN7A07), an AtMAN7 homolog from rapeseed, and demonstrate its function in the dehiscence of rapeseed siliques. We found that BnMAN7A07 was expressed in both vegetative and reproductive organs and significantly highly expressed in leaves, flowers and siliques where the abscission or dehiscence process occurs. Subcellular localization experiment showed that BnMAN7A07 was localized in the cell wall. The biological activity of the BnMAN7A07 protein isolated and purified through prokaryotic expression system was verified to catalyse the decomposition of xylan into xylose. Phenotypic studies of RNA interference (RNAi) lines revealed that down-regulation of BnMAN7A07 in rapeseed could significantly enhance silique dehiscence-resistance. In addition, the expression of upstream silique development regulators is altered in BnMAN7A07-RNAi plants, suggesting that a possible feedback regulation mechanism exists in the regulation network of silique dehiscence. Our results demonstrate that dehiscence-resistance can be manipulated by altering the expression of hemicellulase gene BnMAN7A07, which could provide an available genetic resource for breeding practice in rapeseed which is beneficial to mechanized harvest.

中文翻译：

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下调欧洲油菜 MANANNASE7 基因增强长角果抗裂性

关键信息

甘蓝型油菜中的 MANNAASE7 基因编码位于细胞壁或细胞外空间的半纤维素，可以通过改变MANNAASE7的表达来控制开裂抗性。

抽象的

长角果开裂是植物生殖发育的重要生理过程，但会导致作物严重减产。抗开裂种质资源的缺乏限制了机械化收获的应用，极大地制约了油菜（Brassica napus L.）的生产。半纤维素酶与纤维素酶和果胶酶一起在果实发育和成熟中发挥重要作用。半纤维素酶基因MANNAASE7 ( MAN7 ) 先前已被证明与拟南芥 ( Arabidopsis thaliana ) 长角果的发育和开裂有关。在这里，我们克隆了 BnaA07g12590D ( BnMAN7A07 )，一个AtMAN7油菜籽的同源物，并证明其在油菜长角果开裂中的作用。我们发现BnMAN7A07在营养器官和生殖器官中均有表达，并且在发生脱落或开裂过程的叶、花和长角果中显着高表达。亚细胞定位实验表明BnMAN7A07定位于细胞壁。验证了通过原核表达系统分离纯化的BnMAN7A07蛋白催化木聚糖分解为木糖的生物学活性。RNA 干扰 (RNAi) 系的表型研究表明，BnMAN7A07的下调在油菜籽中可以显着提高长角果的抗裂性。此外，BnMAN7A07-RNAi植物中上游长角果发育调节因子的表达发生了改变，表明长角果开裂调控网络中可能存在反馈调控机制。我们的研究结果表明，可以通过改变半纤维素酶基因BnMAN7A07的表达来控制抗开裂，这可以为油菜育种实践提供可用的遗传资源，有利于机械化收获。