Kok-Jacon Géraldine A, Vincken Jean-Paul, Suurs Luc C J M, Wang Denong, Liu Shaoyi, Visser Richard G F
Graduate School Experimental Plant Sciences, Laboratory of Plant Breeding, Wageningen University, The Netherlands.
Transgenic Res. 2005 Aug;14(4):385-95. doi: 10.1007/s11248-005-0439-0.
The production of dextran in potato tubers and its effect on starch biosynthesis were investigated. The mature dextransucrase (DsrS) gene from Leuconostoc mesenteroides was fused to the chloroplastic ferredoxin signal peptide (FD) enabling amyloplast entry, which was driven by the highly tuber-expressed patatin promoter. After transformation of two potato genotypes (cv. Kardal and the amylose-free (amf) mutant), dextrans were detected by enzyme-linked immunosorbent assay (ELISA) in tuber juices of Kardal and amf transformants. The dextran concentration appeared two times higher in the Kardal (about 1.7 mg/g FW) than in the amf transformants. No dextran was detected by ELISA inside the starch granule. Interestingly, starch granule morphology was affected, which might be explained by the accumulation of dextran in tuber juices. In spite of that, no significant changes of the physicochemical properties of the starches were detected. Furthermore, we have observed no clear changes in chain length distributions, despite the known high acceptor efficiency of DSRS.
研究了马铃薯块茎中葡聚糖的产生及其对淀粉生物合成的影响。来自肠系膜明串珠菌的成熟葡聚糖蔗糖酶（DsrS）基因与叶绿体铁氧还蛋白信号肽（FD）融合，使其能够进入造粉体，该融合基因由块茎中高表达的马铃薯patatin启动子驱动。在转化了两种马铃薯基因型（Kardal品种和无直链淀粉（amf）突变体）后，通过酶联免疫吸附测定（ELISA）在Kardal和amf转化体的块茎汁液中检测到了葡聚糖。Kardal中的葡聚糖浓度（约1.7 mg/g FW）似乎是amf转化体中的两倍。通过ELISA在淀粉粒内部未检测到葡聚糖。有趣的是，淀粉粒形态受到了影响，这可能是由于块茎汁液中葡聚糖的积累所致。尽管如此，未检测到淀粉的物理化学性质有显著变化。此外，尽管已知DSRS具有较高的受体效率，但我们未观察到链长分布有明显变化。
