Regulation Of ABA On Potato Tuber Formation

Potato(Solanum tuberosum L.)is the fourth largest crop after maize,rice and wheat in the world and also an important vegetable crops as well as staple food.Potato tubers are propagation organ,storage organ and product organ.Studing potato tuberosun is important for improving potato yield.Potato tuberosum is regulated by a variety of factors,including light,temperature,sucrose,nitrogen and plant hormones.Previous studies have found the involvement of ABA in the regulation of potato tuberosum and spraying exogenous ABA can promote potato tuberosum.However,no further research has been reported.To investigate the role of ABA on tuberosum,our laboratory cloned an ABA synthesis key enzyme gene StNCED2 and an ABA metabolism key enzyme gene StCYP707A1 and successfully introduced them into potato and genetated StNCED2 overexpression lines and StCYP707A1 overexpression lines.Using the StNCED2 overexpression lines and StCYP707A1 overexpression lines as materials,this paper analyzed the relationship between ABA and potato tuberosum.The results are as follows:Pot experiment showed that average single tuber weight and tuber yield per plant significantly increased in the StNCED2 overexpression lines compared to the wild-type control,whereas significantly reduced in the StCYP707A1 overexpression lines.Analysis on ABA and GA3 content indicated that ABA decreased in the StCYP707A1 overexpression lines and increased in the StNCED2 overexpression lines,whereas GA3 increased in the StCYP707AI overexpression lines and decreased in the StNCED2 overexpression lines.These results reveal that ABA content and tuber yield are positively correlated and ABA and GA3 are mutually antagonistic.Further qRT-PCR analysis on the expression of StGA3ox2,StGA20oxl and StGA3ox2 showed that they were reduced in the StNCED2 overexpression lines and increased in the StCYP707A1 overexpression lines,indicating that ABA can inhibit the expression of potato StGA3ox2,StGA20oxl and StGA20ox3,thus inhibiting the synthesis of GA,resulting GA content decreased and promote tuber formation.