A Wheat β-Patchoulene Synthase Confers Resistance against Herbivory in Transgenic Arabidopsis

• Main Authors: Qingyu Pu, Jin Liang, Qinqin Shen, Jingye Fu, Zhien Pu, Jiang Liu, Xuegui Wang, Qiang Wang
• Format: Article
• Language: English
• Published: MDPI AG 2019-06-01
• Series: Genes
• Subjects: arabidopsis; herbivory; patchoulene; resistance; sesquiterpene; wheat
• Online Access: https://www.mdpi.com/2073-4425/10/6/441

Terpenoids play important roles in plant defense. Although some terpene synthases have been characterized, terpenoids and their biosynthesis in wheat (<i>Triticum aestivum</i> L.) still remain largely unknown. Here, we describe the identification of a terpene synthase gene in wheat. It encodes a sesquiterpene synthase that catalyzes &#946;-patchoulene formation with <i>E,E</i>-farnesyl diphosphate (FPP) as the substrate, thus named as TaPS. TaPS exhibits inducible expression in wheat in response to various elicitations. Particularly, alamethicin treatment strongly induces <i>TaPS</i> gene expression and &#946;-patchoulene accumulation in wheat. Overexpression of <i>TaPS</i> in Arabidopsis successfully produces &#946;-patchoulene, verifying the biochemical function of TaPS in planta. Furthermore, these transgenic Arabidopsis plants exhibit resistance against herbivory by repelling beet armyworm larvae feeding, thereby indicating anti-herbivory activity of &#946;-patchoulene. The catalytic mechanism of TaPS is also explored by homology modeling and site-directed mutagenesis. Two key amino acids are identified to act in protonation and stability of intermediates and product formation. Taken together, one wheat sesquiterpene synthase is identified as &#946;-patchoulene synthase. TaPS exhibits inducible gene expression and the sesquiterpene &#946;-patchoulene is involved in repelling insect infestation.