Ruan Yong-Ling, Llewellyn Danny J, Liu Qing, Xu Shou-Min, Wu Li-Min, Wang Lu, Furbank Robert T
School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW 2308, Australia.
CSIRO Plant Industry, GPO Box 1600, Canberra, ACT 2601, Australia.
Funct Plant Biol. 2008 Jul;35(5):382-393. doi: 10.1071/FP08017.
Successful seed development requires coordinated interaction of the endosperm and embryo. In most dicotyledonous seeds, the endosperm is crushed and absorbed by the expanding embryo in the later stages of seed development. Little is known about the metabolic interaction between the two filial tissues early in seed development. We examined the potential role of sucrose synthase (Sus) in the endosperm development of cotton. Sus was immunologically localised in the cellularising endosperm, but not in the heart-stage embryo at 10 days after anthesis. The activities of Sus and acid invertase were significantly higher in the endosperm than in the young embryos, which corresponded to a steep concentration difference in hexoses between the endosperm and the embryo. This observation indicates a role for the endosperm in generating hexoses for the development of the two filial tissues. Interestingly, Sus expression and starch deposition were spatially separated in the seeds. Silencing the expression of Sus in the endosperm using an RNAi approach led to the arrest of early seed development. Histochemical analyses revealed a significant reduction in cellulose and callose in the deformed endosperm cells of the Sus-suppressed seed. The data indicate a critical role of Sus in early seed development through regulation of endosperm formation.
成功的种子发育需要胚乳和胚之间的协调相互作用。在大多数双子叶植物种子中，胚乳在种子发育后期被不断生长的胚挤压并吸收。关于种子发育早期这两个子代组织之间的代谢相互作用，人们了解甚少。我们研究了蔗糖合酶（Sus）在棉花胚乳发育中的潜在作用。在开花后10天，Sus通过免疫定位在正在细胞化的胚乳中，但不在心形期的胚中。胚乳中Sus和酸性转化酶的活性显著高于幼胚，这与胚乳和胚之间己糖的陡峭浓度差异相对应。这一观察结果表明胚乳在为两个子代组织的发育生成己糖方面发挥作用。有趣的是，Sus的表达和淀粉沉积在种子中在空间上是分开的。使用RNA干扰方法沉默胚乳中Sus的表达导致种子早期发育停滞。组织化学分析显示，Sus抑制种子的变形胚乳细胞中纤维素和胼胝质显著减少。数据表明Sus通过调节胚乳形成在种子早期发育中起关键作用。
