乙烯利诱导甘蔗ACC合成酶基因家族3成员在茎中表达与乙烯释放量和糖分积累的关系

ACC合酶(ACS)是高等植物乙烯生物合成途径中的限速酶。为了弄清楚ACS基因在甘蔗茎中的表达与乙烯释放量、蔗糖积累的关系，在克隆到甘蔗ACS基因3个成员(Sc-ACS1、Sc-ACS2和Sc-ACS3)的基础上，分别以它们作为探针，Northern杂交检验他们在茎中的时空表达。结果表明，甘蔗生长后期，ACS基因三个成员在茎中不同品种和节间持续表达，Sc-ACS1和Sc-ACS2表达维持较低水平，Sc-ACS3维持较高水平。乙烯利处理明显提高3个基因在茎的未成熟和正在成熟节间的表达，且Sc-ACS1和Sc-ACS2在未成熟节间的表达持续时间长达一个月，而Sc-ACS3在未成熟节间的较高水平表达可持续45 d。该结果与甘蔗节间尤其是未成熟和正在成熟节间的乙烯释放量增加以及糖分积累的效应基本一致。相关分析表明，GT17品种乙烯释放量与蔗糖分在处理后14 d和28 d分别极显著和显著负相关，但B1品种未达显著水平。

Expressions of Three Members of ACS Gene Family Induced by Ethephon Relationship of Ethylene Production and Sugar Accumulation in Sugarcane Stems

1-Aminocyclopropane-1-carboxylic acid synthase (ACS) is one of the key rate-limiting enzymes for ethylene biosynthesis in higher plant. In order to study expressions of ACS genes in stalks regulated with ethephon and its correlation with ethylene production and sucrose accumulation in sugarcane, the spatial and temporal expressions of the three genes were tested in the stalks of sugarcane with Sc-ACS1, Sc-ACS2, and Sc-ACS3 as the probes, respectively, based on the cloning of Sc-ACS1, Sc-ACS2 and Sc-ACS3 of ACS gene family. Northern blotting analysis showed that three members of ACS gene family kept expressions during late growth stage in the varieties and internodes with a lower level except of Sc-ACS3. Ethephon treatment increased expressions of the three genes in the immature and maturing internodes. Sc-ACS1 and Sc-ACS2 maintained the highest expression level for 30 d and returned to normal level later, however, Sc-ACS3 kept the highest level for 45 d in the immature stalks. The ethephon-induced gene expressions were in accordance with the significant effects on ethylene production and sucrose accumulation in the immature and maturing internodes. The ethylene production was correlated negatively with the sucrose accumulation in internodes of variety GT17 significantly at P≤0.01 and P≤0.05 at 14 d and 28 d after treatment with ethephon, respectively, but not significantly in the variety B1.