The Effects Of Allene Oxide Cyclase (AOC) Gene Expression Changes On The Rice Allelopathic Potential

Using rice allelopathy to control weeds is one of sustainable agriculture technology and developed in the 21st Century.The formation of rice allelopathy is not only regulated by relevant function genesbut also closely linked with the external environmental stimuli.As a signal transduction molecule,jasmonates plays an important role in plant growth and development,metabolism,disease resistance,stress tolerance,and the inducing expression of defense-related genes.In whilst,jasmonic acid could regulate rice allelopathic potential.Previous studies showed that rice allelopathy was enhanced by spraying exogenous jasmonic acid on it.However,the relation between endogenous jasmonic acid and rice allelopathy have not been documented.Accordingly,in order to study the relation between endogenous jasmonic acid and rice allelopathy,genetic engineering technology was used to change the content of endogenous jasmonic acid in rice.When rice was cocultured with barnyard grass,the expression of allene oxide cyclase(AOC),the key gene of jasmonic acid synthesis pathway,was improved.The expression of AOC gene in allelopathic rice PI312777 and nonallelopathic rice Lemont has incresed by 2.3 and 0.5 times respectively.At the same time,we constructed AOC gene overexpression vector and interference expression vector.The transgene insertion site of transgenic rice was identified by Tail-PCR technique.It was found that the contents of endogenous jasmonic acid is correlative to expression level of AOC gene in rice,and the content of endogenous jasmonic acid has increased by 9%in overexpression transgenic rice but decreased 12%in AOC-RNAi rice lines.The transgenic insertion sites are not located in the function genome on rice according to the result of Tail-PCR.Further,the change expression of rice phenolic acid synthesis relevant genes,terpene synthesis related genes and the changes of phenolics,terpenoids content were detected.The results showed that,by increasing the rice endogenous jasmonic acid content can promote the expression of genes involved in the synthesis of phenolic acids,which secreted more phenolic acids,but there is not obviously relationship between endogenous jasmonic acid and terpene.Finally,the "RCA bioassay method"was used to evaluate the allelopathic potential of transgenic rice plants,the results showed that the allelopathic potential of AOC-Overexpression transgenic rice PI312777 and Lemont has increased by 16.97%and11.25%respectively.the allelopathic potential of AOC-RNAi transgenic rice PI312777 has decreased by 20.21%.The present research shows that the improved content of endogenous jasmonic acid in rice can induce higher expression folds of phenolic acid synthesis related genes,and promote the content of phenolic acids,which contribute to improve rice allelopathic potential.