Zhao Jiping, Newcomb William, Simmonds Daina
Department of Biology, Queen's University, Kingston, Ontario K7L 3N6 Canada.
Plant Cell Physiol. 2003 Dec;44(12):1417-21. doi: 10.1093/pcp/pcg162.
It is currently accepted that 'stress' triggers induction of microspore embryogenesis, and for Brassica napus L. cv. Topas it is heat-shock. It has been postulated that the heat-shock proteins (HSPs) generated during heat stress have a central role in the induction mechanism. To test this hypothesis we developed a microspore induction procedure, using colchicine instead of heat treatment. The level of HSP70 increased significantly during and following the microspore heat treatment while sHSP19 expression was induced at the onset of heat-shock and declined after 8 h. In contrast, induction of embryogenesis with colchicine was not accompanied by elevation of HSP70 nor by induction of sHSP19, indicating that these HSPs are not required for induction of microspore embryogensis in this model system. These data refute the current hypothesis that HSPs have an essential role in triggering microspore embryogenesis.
目前人们普遍认为，“胁迫”会触发小孢子胚胎发生，对于甘蓝型油菜品种Topas而言，胁迫因素是热激。据推测，热胁迫期间产生的热激蛋白（HSPs）在诱导机制中起核心作用。为了验证这一假设，我们开发了一种小孢子诱导程序，使用秋水仙碱代替热处理。在小孢子热处理期间及之后，HSP70水平显著升高，而sHSP19的表达在热激开始时被诱导，并在8小时后下降。相比之下，用秋水仙碱诱导胚胎发生并未伴随着HSP70的升高，也没有诱导sHSP19，这表明在该模型系统中，这些热激蛋白并非诱导小孢子胚胎发生所必需。这些数据反驳了目前热激蛋白在触发小孢子胚胎发生中起关键作用的假设。
