Expression of Potato sAGP Gene and Its Effects on Contents of Starch and Reducing Sugar of Transgenic Potato Tubers
Expression of Potato sAGP Gene and Its Effects on Contents of Starch and Reducing Sugar of Transgenic Potato Tubers
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发表时间：
2005
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通讯作者：
L. Jun
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作者：
L. Jun
通过农杆菌介导法将CaMV 35 S启动子控制下的sAGP基因以正、反义方向导入马铃薯品种E-potato 3和N552-potato，研究sAGP基因对马铃薯块茎淀粉糖代谢的调控作用。PCR扩增和Southern杂交结果表明sAGP基因已整合到马铃薯基因组中，北方杂交结果表明转化基因在马铃薯基因组中正常转录。其中有4个sAGP定向的转基因株系表现出与对照相反的结果，但其余19个株系的淀粉含量平均提高了5%~ 6%，还原糖含量平均降低了20%左右，而A8、C1和C5与相应的对照差异显著。通过反义转化，所有15个衍生系均表现出AGEs活性和淀粉含量平均下降近27%，还原糖含量增加约36%。其中B5、B6、B8和D 7系与对照差异显著。上述结果表明，sAGP可能与AGG酶活性直接相关，AGG酶活性在一定程度上调节马铃薯块茎的淀粉-糖代谢。因此，提高sAGP的表达量是改善马铃薯块茎加工品质的有效途径。
sAGP gene with sense and antisense orientation under the control of CaMV 35S promoter were introduced into potato cultivars E-potato 3 and N552-potato by Agrobacterium-mediated transformation, aiming to elucidate the effects of sAGP gene on regulating metabolism of starch-sugar in potato tubers. The PCR amplification and Southern blot analysis proved the integration of sAGP into potato genome, and the Northern hybridization showed a normal transcription of the transformed gene. Although 4 out of transgenic lines with sense sAGP orientation showed conflict results, the AGPase activity and starch content of the tubers of the other 19 lines increased averagely by 25% and 5%–6%, respectively, and reducing sugar content decreased by around 20%, while lines A8, C1 and C5 had significant difference to the corresponding control. With the antisense transformation, all the 15 derived lines showed average decline in both AGPase activity and starch content by almost 27% and increase in reducing sugar content by about 36%. Among them, lines B5, B6, B8 and D7 were significantly different with the control. The present results suggested that sAGP may directly relate to AGPase activity that could regulate, to a certain extent, starch-sugar metabolism of potato tubers. Therefore increase in sAGP expression could be an efficient approach to improve the processing quality of potato tubers.