BASIC STUDIES ON THE EVALUATION OF FLOWER SCENTAND ITS MOLECULAR BREEDING

我们一直在关注槐花花序散发出的难闻气味。通过顶空吸收/气相色谱分析数据与感官测试数据的比较，发现甲基丁酸（3-甲基丁酸和2-甲基丁酸）是表征恶臭的成分，甲基丁酸是由氨基酸经酮酸合成的。醇酰基辅酶a转移酶（AAT）催化甲基乙酸发生酯化反应，而用乙醇处理花期没有发生酯化反应；然而，当使用异戊醇时，导致乙酸异戊酯和甲基丁酸异戊酯的数量增加，而从花序中释放的甲基丁酸的水平降低。钛也促进了甲基丁酸的酯化反应，但含钛的预处理防腐剂对去除气味没有效果，可能是因为钛在茎中的流动性差。对氨基酸（亮氨酸和异亮氨酸）分解代谢途径中产生甲基丁酸的相关基因进行了Northern分析。氨基酸转氨酶基因表达在亮氨酸处理的花序中增加，甲基丁酸释放量也增加。为了详细研究气味形成的遗传模式，我们获得了G. elegance Bied var. carminea hort具有不同程度气味的自交细粒。以两个品种为材料，建立转化体系，进一步进行分子育种。采用plG121-HM载体导入GUS，进行植株再生和GUS表达检测。

We have been focusing on the unpleasant odor emitted from Gypsophita inflorescences. By comparing the data of headspace absorption / gas chromatography analysis with those of sensory test, it was revealed that the methylbutyric acids (3-methylbutyric acid and 2-methylbutyric acid) are the components which characterize the unpleasant odor and that methybutyric acids are synthesized from amino acids through keto acids. Esterification of metylbytyric acids , which is catalyzed by alcohol acyl-CoA transferase (AAT), did not occurred by a treatment of florescences with ethanol; however, it occurred with isoamyl alcohol, resulted in increased amount of isoamyl acetate and isoamyl metylbutyrate and decreased level of methylbutyric acids emitted from inflorescences. Titanium also promoted esterification of methylbutyric acids but pretreatment preservatives containing titanium had no effect on removing odor because of presumably the poor mobility of titanium in the stems. Northern analysis was conducted on the gene involved in amino acids (leucine and isoleucine) catabolism pathway which lead to methylbutyric acids. Gene expression of amino acid transaminase increased in the inflorescences treated with leucine, which also emitted increased amount of methylbutyric acids. To study the mode of inheritance of odor formation in detail, we obtained selfed fines with varying levels of odor of G. elegance Bied var. carminea hort. Two cultivars of G. elegance Bied were used to establish transformation system for further molecular breeding. GUS was introduced by using plG121-HM vector, plants were regenerated and the GUS expression was detected.