MADS Box Transcript Amount is Affected by Ethylene during Abscission

Thinning of young fruit is an important agronomical practice to ensure the maximum economic production. This practice is based on the control of the natural self thinning process occurring during fruit development. At the early stages of fruit development (fruitlet), the vegetative part of the tree is competing with the reproductive part of the tree and within the fruit clusters the different fruitlets are competing with each other. As a result the least fit organ abscises, Ethylene and auxin play a central role in this event but the role of ethylene is not thoroughly understood because in other systems abscission occurs partly with ethylene independent processes. We have followed the early development of fruitlets and studied the transcription patterns of MADS-box and ethylene related transcripts. Furthermore, we verified that ethylene has an effect on the expression of some ethylene related and MADS BOX genes. We propose that the ethylene burst during abscission induction is similar to a stage 2 ethylene system and it is related to fruitlet growth by affecting transcript amount of MADS-BOXes which modulate seed development and cortex growth.