GENE ACTION DURING CELLULAR DIFFERENTIATION AND RELATED ORGANOGENESIS IN CROPS CULTURED,IN VITRO

利用马铃薯离体生根系统，在马铃薯发育早期特异性检测到马铃薯kunitz型蛋白酶抑制剂（PKPI） mRNA的积累，有望成为马铃薯生根的分子标记。此外，PKPI-mRNA的积累也发现，当组织在冷却到温暖的气氛中升高温度和添加茉莉酸时。ABA在长期培养的水稻愈伤组织中诱导的新蛋白（14、18.5、24.5、45kDa）在小块再生后消失，而在完整的成熟种子胚中存在相同分子量的蛋白，在种子萌发时消失。在培养基中添加ABA可在一定程度上维持胚性愈伤组织的培养。这种激素可能与水稻体细胞胚胎的再生和正常胚胎发生有关。为了将外源DNA引入培养的马铃薯、烟草、胡萝卜和水稻的细胞中，已经开发了一种电穿孔原生质体中瞬时基因表达的方案。当同源基因由NOS和35S启动子驱动，以及马铃薯块茎PKPI和水稻肌动蛋白基因actin -1的上游序列驱动时，该方法产生了大量的报告酶b -葡糖醛酸酶（GUS）。与马铃薯、烟草、胡萝卜和水稻细胞的表达比较表明，瞬时检测可以用于研究启动子的激活和增强子的功能。

By using in vitro tuberization system of potato, the accumulation of potato kunitz type proteinase inhibitor (PKPI) mRNA was specifically detected in tubers during the early stage of development, and thus expected to be a molecular marker of potato tuberization. Furthermore, the accumulation of PKPI-mRNA was also found when tissues were treated with cool to warm atmosphere by ascending temperature, and by addition of jasmonic acid.The novel proteins (14,18.5,24.5,45kDa) were induced by ABA in long-term cultured callus of rice and disappeared after plentlet regeneration, while proteins of the same molecular weight existed in intact mature seed embryos and disappeared when the seeds were germinating. Sustaining of embryogenic callus cultures could be some extent achieved by the addition of ABA in medium. This hormone could be responsible for regenerating somatic embryos and for normal embryogeny in rice plants.A protocpl of the trangent gene expression in electroporated protoplasts has been developed for the introduction of foreign DNA into cells from cultured potato, tobacco, carrot, and rice. The method yields high amounts of the reporter enzyme B-glucuronidase (GUS) when cognate genes are driven by the promotors of NOS and 35S,and by upstream sequences of PKPI from potato tuber and Actin-1 from rice actin genes. Comparisons with expression in potato, tobacco, carrot, and rice cells indicate that trangent assays can be used to investigate promotor acivation and enhancer function.