title: Expression ofIPTin Asakura-sanshoo (Zanthoxylum piperitum(L.) DC. f.inermeMakino) Alters Tree Architecture, Delays Leaf Senescence, and Changes Leaf Essential Oil Composition.
abstract: TheIPTgene encodes isopentenyl pyrophosphate transferase, a key enzyme in cytokinin biosynthesis. We introducedIPTunder the control of the CaMV35S promoter into Asakura-sanshoo (Zanthoxylum piperitum(L.) DC. f.inermeMakino) via stableAgrobacterium tumefaciens-mediated transformation. Three of 3-year-old transgenic Asakura-sanshoo lines Y5, Y16, and Y17 were used to evaluate the effects ofIPTexpression on the morphological characteristics, leaf senescence, and essential oil composition. IntroducedIPTinto Asakura-sanshoo stimulated an increase in cytokinin content and a decrease in auxin level. The increase in the cytokinin/auxin ratio affected the tree architecture in 3-year-old transgenic lines. The phenotypes of transgenic lines included reduced stem elongation, decreased leaf surface area, increased branching, and delayed leaf senescence. The expression ofIPTin Asakura-sanshoo also affected the leaf essential oil composition. The amount of oxygenated sesquiterpenoid compounds in Y5 and Y16 was 21.1 and 15.8 % higher, respectively, than that in wild type (WT). The amount of aromatic compounds in Y5 and Y16 was 2.9 and 24.6 % lower, respectively, than that in WT. These results show thatiptexpression in Asakura-sanshoo conferred desirable traits, including a dwarf growth habit, delayed senescence, and increased concentrations of some sesquiterpenoid compounds.
authors.affiliation: The Key Laboratory of Plant Resources Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), Institute of Agro-Bioengineering and College of Life Sciences, Guizhou University, Guiyang, 550025 People's Republic of China.
authors.forename: Xiao-Fang
authors.initials: XF
authors.lastname: Zeng
authors.affiliation: The Key Laboratory of Plant Resources Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), Institute of Agro-Bioengineering and College of Life Sciences, Guizhou University, Guiyang, 550025 People's Republic of China.
authors.forename: De-Gang
authors.initials: DG
authors.lastname: Zhao
keywords: Asakura-sanshoo; Essential oil; IPT gene; Leaf senescence