Characterization of Early Molecular Events During Fruit Abscission in Higher Plants

本研究的长期目标是阐明高等植物果实脱落的分子机制。据报道，菜豆裂叶过程中离区纤维素酶(β，1：4葡聚糖水解酶)含量增加。我们还知道，外源乙烯的加入可以加速纤维素酶活性的增加。最近分离到一个与菜豆纤维素酶mRNA互补的cDNA克隆，与之互补的信使RNA在乙烯处理菜豆后几小时内在离区急剧增加。动力学表明，纤维素酶在发出脱落信号之前发生了其他细胞事件。要确定乙烯促进果实脱落的机制，一种方法是检查那些对外部施加的乙烯快速反应的基因。Klein博士建议分离和鉴定在番茄离区快速诱导的乙烯反应基因，并检测它们在番茄果实脱落过程中的表达。

The long term goal of this research is to elucidate the molecular mechanisms that regulate fruit abscission in higher plants. It has been documented that cellulase (beta, 1:4 glucan glucanhydrolase) increases in the abscission zone of Phaseolus vulgaris during leaf fracture. It is also known that this increase in cellulase activity can be accelerated by the addition of exogenous ethylene. A cDNA clone, complementary to bean cellulase mRNA has been recently isolated and messenger RNA complementary to it has been shown to increase dramatically in the abscission zone several hours after ethylene treatment of bean. The kinetics suggest that other cellular events precede cellulase appearance in signalling abscission. One approach to identifying the mechanism through which ethylene promotes fruit abscission is to examine those genes which respond rapidly to externally applied ethylene. Dr. Klein proposes here to isolate and characterize ethylene responsive genes that are rapidly induced in the abscission zone and examine their expression during fruit abscission in tomato.