The Influence Of Wounding On Phospholipase A₂ In Latex Of Brasiliensis(Rubber Tree)

Phospholipase A2 (PLA2) and lipoxygenase(LOX) may have some important functions in plant metabolism and signal transduction. This paper mainly research the effect of wounding to PLA2 and LOX in C-serum of latex, and discussed the relationship between the two enmyzes and the rubber clones,discussed the effects regulation of wounding (tapping and Ethrel) on PLA2,and the responds of PLA2 as a molecular signal to wounding and Ethrel.According to the theory of signal transduction of wounding,the PLA2 was studied in the C-serum of latex.This result displayed the PLA2 activity had no apparent connection on latex yield.The result was incosisted with some pubulished documents which proposed that PLA2 was an inhibit factor in synthesise of latex. On the condition of wounding(tapping is machanical wounding),the activities of PLA2 was analyzed in C-serum of latex in the young rubber tree.The relations of PLA2 and LOX was dicussed on the different Ethrel-stimulating dose,Ethrel-stimulating time and different clones of rubber tree.The results showed that wounding and Ethrel-treatment could induce the activities of PLA2 in latex. But the inducing efficiency of Ethrel wasn't in linear with Ethrel quantity,and the LOX activity is inconsistent with the PLA2.It was conclude that LOX activity may be regulated by the other factors, or its substrates have the other sources. Then PLA2 was also purified and its partial characteristic were identified.The possible regulation mechanism of PLA2 was discussed in this paper.The PLA2 gene partial cDNA sequence was obtained by RT-PCR,and sequence analyses displayed it was identical with the sequence of Hev b7 published by Kostyal D.A.(1998). Hev b7 is similar to patatin and has phospholipase A2 activity.The Northern blotting hybridization using PLA2 probe labeled with Digoxin.The resultshowed that the expression levels of PLA2 were different under various treatments. RY 7-33-97 (Ethrel) was the strongest in four treatment, the PR107 (no Ethrel) was the weakest,RY 7-33-97 (no Ethrel) was stronger than the PR107 (Ethrel).In the young tree experiment,the primary tapping was the weakest, the first tapping after treatment (Ethrel) was stronger than the first tapping(no Ethrel).These resultses were in accordance with phospholipase A2 activity .