Wuhan botanical garden plant genetic experts han peng, Li Shaohua recently reported a study. Apple will change from acid sweet because such dicotyledonous plants compared with single cotyledon gramineae, GBSS only GBSSII single gene family, and SBEII only SBEIIa genes are single family, these differences in the genetic level may have contributed to apple starch characteristics different from the main cause of corn starch.

 

Han peng said, starch synthesis is more complex, the encoding granule combined with starch synthase (GBSS), soluble starch synthase (SS), starch branching enzyme (SBE), starch branching enzyme (DBE), and many other gene regulation.

 

"Starch is not sweet, so the flavor of the apple before maturity is mainly controlled by malic acid, so they are sour. Along with the maturity of the fruit, apple inside began to hydrolysis of starch into sugar metabolism, slowly converted to glucose, fructose and sucrose, and malic acid is on the decrease, so the apple is ripe, they became sweet." Han peng said.

 

However, glucose, fructose and sucrose sweetness is not the same as the three sugar, fructose is the most sweet, followed by the sucrose, glucose and sweetness. Han peng said: "the three sugar percentage in apple is a very complex gene regulation network to determine, scientists are still looking for the gene regulatory network."

 

The researchers also found an interesting phenomenon: the apple cultivars and wild resources from more than 400 testing found that the acid is wild apple resources, its organic acid content than cultivated varieties of up to 56 times above. Han peng said: "this shows that human in the process of apple long domestication, gradually eliminate the organic acid more apple, domesticated more sweet apple."