中文摘要：

香蕉是世界主要水果之一,对乙烯非常敏感,属于呼吸跃变型果实。目前,香蕉果实后熟机理还未完全探明,后熟过程中己糖激酶（HXK）与乙烯的关系还不清楚。通过BLAST比对从香蕉基因组数据库中发现HXK基因家族的11个成员,经克隆获得这些基因的序列,并研究HXKs基因在香蕉果实自然后熟过程中的转录表达谱,重点研究乙烯利、甘露糖、NAG和1-MCP对HXKs基因表达、HXK酶活和内源乙烯生物合成的影响。结果表明：在香蕉果实后熟过程中HXKs基因呈现差异性表达,乙烯利上调大多数HXKs基因的表达和HXK酶活,1-MCP的作用正好相反,这表明外源乙烯正作用于HXK。另一方面,甘露糖加快内源乙烯生物合成,NAG却推迟内源乙烯生物合成,这说明HXK正作用于内源乙烯生物合成。所以,在香蕉果实后熟过程中乙烯和HXK之间存在相互促进的关系。这将为进一步阐明香蕉果实后熟机制提供理论依据,也将为香蕉果实保鲜新技术的挖掘提供新思路。

英文摘要：

Banana is one of the staple fruit in the world that belongs to the respiratory climacteric fruit and is very sensitive to ethylene. The mechanism of banana fruit ripening is not fully proved at present, and the relationship between hexokinase （HXK） and ethylene during banana fruit ripening is not clear yet. In this study, the 11 members of the HXK gene family were retrieved from the banana genomic database by Basic Local Alignment Search Tool （BLAST）, and the sequences of HXKs genes were obtained by cloning. Simultaneously, the expression profiles of the HXKs genes were researched on transcriptional level in naturally ripened banana fruit. Tben, it was mainly studied how ethephon, mannose, N-acetylglucosamine （NAG） and 1-methylcyclopropene （1- MCP） affected the expression of HXKs genes, HXK activity, and ethylene content in the treated banana fruit with the four reagents. The results showed that the expression profiles of HXKs genes were differential during the ripening process of banana fruit. The expression of most HXKs genes and HXK activity increased by ethephon during ripening porcess, although 1-MCP having the contrary effect, which indicated that ethylene positively affected the functions of HXK. On the other hand, mannose induced ethylene biosynthesis, but NAG suppressed ethylene biosynthesis, which implied that HXK also promoted ethylene biosynthesis. Those results suggest that there was a positive interaction between ethylene and HXK during ripening process of banana fruit. It would provide a theoretical basis for further elucidating the mechanism of banana fruit ripening and also help us discover a novel strategies to dig new methods of fresh-keeping for banana fruit.