Laser diffraction: A new tool for identification and studies of physiological effectors involved in aggregation-coagulation of the rubber particles from Hevea latex.

Latex coagulation is the main limiting factor of rubber yield in Hevea brasiliensis (rubber tree). Using laser diffraction, we set up and optimized a new method for monitoring the kinetics of rubber particle (RP) aggregation, a prerequisite for latex coagulation. In contrast to any previous method used, laser diffraction allows continuous monitoring changes in size of RP aggregates, thereby allowing characterization and quantification of the processes involved in latex coagulation. Using this technique, we confirm that RP aggregating factors are proteins compartmentalized within latex cell vacuoles (lutoids), which, especially at relatively acidic physiological pH, can induce formation of RP aggregates large enough to induce plugging of severed latex vessel extremities. Conversely, latex cytosol was found to harbor anti-aggregating proteins. Further, we were able to titrate the RP-aggregating efficiency of the intralutoidic serum and the anti-aggregating efficiency of the cytosol. Preliminary assays showed that these two parameters were correlated with the yield potential of the tested rubber clones. This method will allow identification and characterization of proteins involved in latex coagulation, hence in rubber yield. We suggest that laser diffraction could be used to monitor the kinetics and characterize the physiological processes involved in aggregation of any particles, organelles or cells.