title: Involvement of Auxin and Brassinosteroid in Dwarfism of Autotetraploid Apple (Malus × domestica).
abstract: The plant height is an important trait in fruit tree. However, the molecular mechanism on dwarfism is still poorly understood. We found that colchicine-induced autotetraploid apple plants (Malus × domestica) exhibited a dwarf phenotype. The vertical length of cortical parenchyma cells was shorter in autotetraploids than in diploids, by observing paraffin sections. Hormone levels of indoleacetic acid (IAA) and brassinosteroid (BR) were significantly decreased in 3- and 5-year-old autotetraploid plants. Digital gene expression (DGE) analysis showed that the differentially expressed genes were mainly involved in IAA and BR pathways. microRNA390 was significantly upregulated according to microarray analysis. Exogenous application of IAA and BR promoted stem elongation of both apple plants grown in medium. The results show that dwarfing in autotetraploid apple plants is most likely regulated by IAA and BR. The dwarf phenotype of autotetraploid apple plants could be due to accumulation of miR390 after genome doubling, leading to upregulation of apple trans-acting short-interfering RNA 3 (MdTAS3) expression, which in turn downregulates the expression of MdARF3. Overall, this leads to partial interruption of the IAA and BR signal transduction pathway. Our study provides important insights into the molecular mechanisms underlying dwarfism in autopolyploid apple plants.
authors.affiliation: College of Horticulture, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110866, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Ma
authors.affiliation: College of Horticulture, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110866, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Xue
authors.affiliation: College of Horticulture, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110866, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: College of Horticulture, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110866, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Zhang
authors.affiliation: Research Institution of Pomology, Chinese Academy of Agricultural Sciences, Xingcheng, Liaoning 125100, China.
authors.forename: Chunqing
authors.initials: C
authors.lastname: Ou
authors.affiliation: College of Plant Protection, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110866, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.affiliation: College of Horticulture, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110866, China.
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D060406:Brassinosteroids / Q000378:metabolism*; D002678:Chimera / Q000235:genetics / Q000378:metabolism; D018745:Genome, Plant; D007210:Indoleacetic Acids / Q000378:metabolism*; D027845:Malus / Q000235:genetics / Q000378:metabolism; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D057891:Tetraploidy
chemical_list: D060406:Brassinosteroids; D007210:Indoleacetic Acids; D035683:MicroRNAs; D018749:RNA, Plant