Study On The Mechanism Of Blue Light Inhibition Of Ethylene Synthesis During Ripening Of 'Nanguo'pear

The ripening of fruit is an important factor to determine its storage.The study on the mechanism of fruit ripening and regulation has important theoretical and practical significance for the regulation of fruit storage.Pyrus ussuriensis Maxim is the unique northern pear resources in our country,most of pyrus usuriensis Maxim including 'Nanguo' pear is climacteric fruit.The ripening process of climacteric fruit is mainly regulated by ethylene.In addition,light,temperature and other environmental factors can also regulate the ripening process of fruit.In recently years,many studies have shown that blue light can inhibit the ethylene synthesis during the ripening of climacteric fruit,thus affecting the storage of fruit,but its molecular mechanism is not clear.In this study,'Nanguo' pear fruits were used to study the mechanism of how PuHYHl to inhibit the expression of PuACS1 to regulate ethylene synthesis during fruit ripening process.The main results are as follows:1 From the pear genome we cloned homologous gene of HY5,PuHYHl and ERF,ACS and ACO.The expression profiles of these genes were analyzed,finding that blue light could induce the expression of PuHYHl and PuERF2,while inhibit the expression of PuACS1.2 Yeast one hybrid and EMS A experiments showed that PuHYHl and PuERF2 were able to bind to the promoter of PuACSl.PuHYH1 and PuERF2 negatively regulated the expression of PuACSl in the GUS gene activity assay.3 Yeast two hybrid and Pull-down found that PuHYHl could bind with PuERF2.4 The GUS gene activity assay showed that the interaction between PuHYHl and PuERF2 can enhance the negative regulation of PuERF2 on PuACSl.These results indicate that PuHYHl and PuERF2 can negatively regulate the expression of PuACSl,the interaction between PuHYHl and PuERF2 can enhance the negative regulation of PuACS1 expression.Blue light may inhibit the expression of PuACS1 through the above two ways to inhibit ethylene synthesis.The results of this study elucidated the mechanism of blue light inhibit the ethylene synthesis of Nanguo pear,which provided an important theoretical basis for improving the storage of Nanguo Pear.