Molecular mechanism underlying ethylene stimulation of latex production in rubber tree (Hevea brasiliensis)

Abstract

Ethephon (an ethylene releaser) is commonly used to enhance latex productivity of rubber tree ( Hevea brasiliensis ), but the underlying mechanism has been elusive. The review presents the recent advances in understanding the molecular mechanism of increasing latex production in rubber tree by ethylene application. Rubber tree (Hevea brasiliensis) is currently the only commercial sources of natural rubber which is an important industrial material. Application of ethephon (an ethylene generator) has been a measure extensively adopted in worldwide rubber plantations to increase the productivity of rubber tree since the 1960s. In the recent years, adoption of genomic, transcriptomic, and proteomic approaches has brought great progress in understanding the mechanism of ethylene stimulation of latex yield. In this review, an update on the molecular mechanism of ethylene stimulation of latex production in H. brasiliensis is presented. Ethylene stimulation can be roughly ascribed to the acceleration of latex regeneration and the prolongation of the flow of latex. The relevant biochemical pathways and processes are comprehensively reviewed. The possibility that the limiting factors of the biosynthesis of rubber identified in bark glycolysis and photosynthetic carbon fixation can be utilized in molecular diagnostic and genetic engineering for rubber high-yielding variety improvement is discussed. Unsolved problems of the ethylene stimulation and a major challenge to understand the regulatory mechanism of the ethylene stimulation are also indicated.