Characterization of spermidine hydroxycinnamoyl transferases from eggplant (Solanum melongena L.) and its wild relative Solanum richardii Dunal  

作　　者：Hui Peng Tianbao Yang Bruce D Whitaker Frances Trouth Lingfei Shangguan Wen Dong Wayne M Jurick 

机构地区：[1]Agricultural Research Service of U.S.Department of Agriculture,Food Quality Laboratory,Beltsville Agricultural Research Center,Beltsville,20705,MD,USA [2]Horticulture&Landscape College,Hunan Agricultural University,Changsha,410128,Hunan,China [3]College of Horticulture,Nanjing Agricultural University,Nanjing,210095,Jiangsu,China [4]Department of Plant Science,University of Tennessee,Knoxville,37996,TN,USA

出　　处：《Horticulture Research》2016年第1期21-29,共9页园艺研究（英文）

基　　金：This research was funded by USDA-ARS NP306 project no.8042-43000-012-00D.

摘　　要：Eggplant produces a variety of hydroxycinnamic acid amides(HCAAs)that have an important role in plant development and adaptation to environmental changes.In this study,we identified and characterized a spermidine hydroxycinnamoyl transferase(SHT)from eggplant(Solanum melongena)and its wild relative S.richardii,designated as SmSHT and SrSHT,respectively.SmSHT was abundant in flowers and fruits,whereas the level of SrSHT was remarkably low in all tissues.Heat-shock/drought treatment stimulated the expression of SmSHT in both leaves and fruits,indicating its involvement in plant stress response.Both SHT polypeptides had extremely high identity with just five amino-acid substitutions.Recombinant SmSHT catalyzed the synthesis of mono-,bi-and tri-acylated polyamines.Using caffeoyl-CoA as the acyl donor,SmSHT preferred spermidine as the acyl acceptor.When spermidine was the acyl acceptor,the donor preference order for SmSHT was caffeoyl-CoA>feruloyl-CoA>ρ-coumaroyl-CoA.SrSHT exhibited the same substrate specificity as SmSHT,yet exhibited significantly higher catalytic activity than SmSHT.For example,under caffeoyl-CoA and spermidine,Kcat of SrSHT was 37.3%higher than SmSHT.Molecular modeling suggests that five amino-acid substitutions in SrSHT result in four alterations in their predicted 3D structures.In particular,the conserved Lys402 adjacent to the DFGWG motif,and Cys200 in the crossover loop in SmSHT were replaced by Glu and Ser in SrSHT.These substitutions may contribute to the enhanced activity in SrSHT.Our study provides a platform to generate HCAA rich fruits for eggplant and other solanaceous crops.

关 键 词：donor ACCEPTOR FLOWERS 

分 类 号：O62[理学—有机化学]