Ecology School, Shanghai Institute of Technology, Shanghai, 201418, China.
Mol Biol Rep. 2013 Jul;40(7):4581-90. doi: 10.1007/s11033-013-2550-2. Epub 2013 May 5.
The role of ethylene in induction of aerenchyma formation and ethanolic fermentation in waterlogged roots of Dendranthema zawadskii and D. nankingense, two species that differ with respect to waterlogging tolerance, was examined. In the more tolerant D. zawadskii, but not in D. nankingense, ethylene accelerated programmed cell death and promoted formation of lysigenous aerenchyma, both of which were inhibited by treatment with the ethylene inhibitor 1-methylcyclopropene. Waterlogged D. zawadskii roots generated a higher quantity of endogenous ethylene than did those of D. nankingense. In waterlogged D. zawadskii roots, transcription of the genes encoding alcohol dehydrogenase (EC 1.1.1.1) and pyruvate decarboxylase (EC 4.1.1.1) increased rapidly but transiently, whereas expression of these genes in D. nankingense increased gradually and over a longer period. In D. nankingense, waterlogging elevated both alcohol dehydrogenase and pyruvate decarboxylase activity, and the production of ethanol and acetaldehyde was increased in the presence of exogenous ethylene and inhibited by 1-methylcyclopropene. In D. zawadskii, in contrast, after a prolonged episode of waterlogging stress, exogenous supply of ethylene suppressed the production of ethanol and acetaldehyde, whereas exogenous 1-methylcyclopropene enhanced their production. In the more tolerant Dendranthema species, ethylene appeared to signal an acceleration of both waterlogging-induced programmed cell death and aerenchyma formation and to alleviate ethanolic fermentation, whereas in the more sensitive species ethylene activated fermentation and increased the release of ethanol and acetaldehyde, which are by-products probably responsible for the collapse of the waterlogging-damaged root.
我们研究了乙烯在诱导受涝胁迫的菊属（Dendranthema）植物细胞程序性死亡和形成通气组织以及乙醇发酵过程中的作用，供试材料包括两个种，即较耐涝的 Dendranthema zawadskii 和不耐涝的 D. nankingense。在更耐涝的 D. zawadskii 中，乙烯加速程序性细胞死亡并促进溶生通气组织形成，这两个过程均可被乙烯抑制剂 1-甲基环丙烯所抑制；而在不耐涝的 D. nankingense 中则没有观察到这种作用。受涝胁迫的 D. zawadskii 根中内源乙烯的生成量显著高于 D. nankingense。在受涝胁迫的 D. zawadskii 根中，编码醇脱氢酶（EC 1.1.1.1）和丙酮酸脱羧酶（EC 4.1.1.1）的基因转录迅速但短暂增加，而在 D. nankingense 中这些基因的表达则逐渐增强且持续时间较长。在 D. nankingense 中，受涝胁迫提高了醇脱氢酶和丙酮酸脱羧酶的活性，外加乙烯可促进其乙醇和乙醛的生成，而 1-甲基环丙烯则可抑制这种作用。相反，在较耐涝的 D. zawadskii 中，长期水淹胁迫后，外加乙烯抑制了乙醇和乙醛的生成，而外加 1-甲基环丙烯则促进了它们的生成。在更耐涝的菊属植物中，乙烯似乎通过加速水淹诱导的程序性细胞死亡和通气组织形成来减轻乙醇发酵，而在更敏感的种中，乙烯则激活发酵并增加乙醇和乙醛的释放，这些副产物可能是导致受涝损伤根崩溃的原因。
