Suppression of extracellular invertase inhibitor gene expression improves seed weight in soybean (Glycine max).
Suppression of extracellular invertase inhibitor gene expression improves seed weight in soybean (Glycine max).
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DOI：
10.1093/jxb/erw425
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发表时间：
2017-01-01
影响因子：
6.9
通讯作者：
Liu L
中科院分区：
文献类型：
--
作者：
Tang X;Su T;Han M;Wei L;Wang W;Yu Z;Xue Y;Wei H;Du Y;Greiner S;Rausch T;Liu L
在大豆（Glycine max）中研究了GmCIF1和GmC/VIF1作为转化酶抑制剂的作用，发现沉默GmCIF1表达可提高翻译后细胞外转化酶活性，从而增加种子重量。细胞壁转化酶（CWI）和液泡转化酶（VI）在植物生长过程中发挥着多种功能。除了依赖于转录和转录后调控外，越来越多的证据表明CWI和VI也受到小抑制蛋白的翻译后调控。尽管这具有重要意义，但在大豆中，编码抑制剂的基因、它们的分子和生化特性以及它们在调节种子生产中的潜在作用尚未得到很好的研究。在本研究中，通过异种表达鉴定了两种转化酶抑制剂GmCIF1和GmC/VIF2在体外具有抑制活性。转录本分析表明，它们主要在发育中的种子和对ABA的响应中表达。根据这一点，对主要靶点的调查显示，表达yfp融合构建体后，烟草表皮的外质体亚细胞定位。使用RNAi转基因植物的研究表明，CWI活性显著升高，种子重量改善，成熟种子中己糖、淀粉和蛋白质的积累也增加。进一步对GmCIF1与几个假定的CWI基因的共表达分析证实了GmCIF1对影响种子重量的CWI的调节主要取决于翻译后机制。总的来说，研究结果表明，通过沉默GmCIF1表达，翻译后CWI的升高通过微调蔗糖代谢和汇强度来协调种子成熟过程。
The roles of GmCIF1 and GmC/VIF1 as invertase inhibitors were examined in vitro in soybean (Glycine max), and post-translational elevation of extracellular invertase activity by silencing GmCIF1 expression was found to increase seed weight. Cell wall invertase (CWI) and vacuolar invertase (VI) play multiple functions in plant growth. As well as depending on transcriptional and post-transcriptional regulation, there is growing evidence that CWI and VI are also subject to post-translational control by small inhibitory proteins. Despite the significance of this, genes encoding inhibitors, their molecular and biochemical properties, and their potential roles in regulating seed production have not been well documented in soybean (Glycine max). In this study, two invertase inhibitor isoforms, GmCIF1 and GmC/VIF2, were characterized to possess inhibitory activities in vitro via heterologous expression. Transcript analyses showed that they were predominantly expressed in developing seeds and in response to ABA. In accordance with this, surveys of primary targets showed subcellular localizations to the apoplast in tobacco epidermis after expressing YFP-fusion constructs. Investigations using RNAi transgenic plants demonstrated marked elevations of CWI activities and improvements in seed weight in conjunction with higher accumulations of hexoses, starch, and protein in mature seeds. Further co-expression analyses of GmCIF1 with several putative CWI genes corroborated the notion that GmCIF1 modulation of CWI that affects seed weight is mainly contingent on post-translational mechanisms. Overall, the results suggest that post-translational elevation of CWI by silencing of GmCIF1 expression orchestrates the process of seed maturation through fine-tuning sucrose metabolism and sink strength.