title: Apple MdACS6 Regulates Ethylene Biosynthesis During Fruit Development Involving Ethylene-Responsive Factor.
abstract: Ethylene biosynthesis in plants involves different 1-aminocyclopropane-1-carboxylic acid synthase (ACS) genes. The regulation of each ACS gene during fruit development is unclear. Here, we characterized another apple (Malus×domestica) ACS gene, MdACS6. The transcript of MdACS6 was observed not only in fruits but also in other tissues. During fruit development, MdACS6 was initiated at a much earlier stage, whereas MdACS3a and MdACS1 began to be expressed at 35 d before harvest and immediateley after harvest, respectively. Moreover, the enzyme activity of MdACS6 was significantly lower than that of MdACS3a and MdACS1, accounting for the low ethylene biosynthesis in young fruits. Overexpression of MdACS6 (MdACS6-OE) by transient assay in apple showed enhanced ethylene production, and MdACS3a was induced in MdACS6-OE fruits but not in control fruits. In MdACS6 apple fruits silenced by the virus-induced gene silencing (VIGS) system (MdACS6-AN), neither ethylene production nor MdACS3a transcript was detectable. In order to explore the mechanism through which MdACS3a was induced in MdACS6-OE fruits, we investigated the expression of apple ethylene-responsive factor (ERF) genes. The results showed that the expression of MdERF2 was induced in MdACS6-OE fruits and inhibited in MdACS6-AN fruits. Yeast one-hybrid assay showed that MdERF2 protein could bind to the promoter of MdACS3a. Moreover, down-regulation of MdERF2 in apple flesh callus led to a decrease of MdACS3a expression, demonstrating the regulation of MdERF2 on MdACS3a. The mechanism through which MdACS6 regulates the action of MdACS3a was discussed.
authors.affiliation: College of Horticulture, Shenyang Agricultural University, Shenyang, 110866 China These authors contributed equally to this work.
authors.forename: Tong
authors.initials: T
authors.lastname: Li
authors.affiliation: College of Horticulture, Shenyang Agricultural University, Shenyang, 110866 China These authors contributed equally to this work.
authors.forename: Dongmei
authors.initials: D
authors.lastname: Tan
authors.affiliation: Division of Apple Breeding, Institute of Pomology, Liaoning Academy of Agricultural Sciences, Xiongyue, 115009 China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Liu
authors.affiliation: College of Horticulture, Shenyang Agricultural University, Shenyang, 110866 China.
authors.forename: Zhongyu
authors.initials: Z
authors.lastname: Jiang
authors.affiliation: College of Horticulture, Shenyang Agricultural University, Shenyang, 110866 China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Wei
authors.affiliation: College of Horticulture, Shenyang Agricultural University, Shenyang, 110866 China.
authors.forename: Lichao
authors.initials: L
authors.lastname: Zhang
authors.affiliation: College of Horticulture, Shenyang Agricultural University, Shenyang, 110866 China.
authors.forename: Xinyue
authors.initials: X
authors.lastname: Li
authors.affiliation: College of Horticulture, Shenyang Agricultural University, Shenyang, 110866 China.
authors.forename: Hui
authors.initials: H
authors.lastname: Yuan
authors.affiliation: College of Horticulture, Shenyang Agricultural University, Shenyang, 110866 China adwang333@163.com.
authors.forename: Aide
authors.initials: A
authors.lastname: Wang
mesh_terms: D005030:Ethylenes / Q000378:metabolism*; D005638:Fruit / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D027845:Malus / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*
chemical_list: D005030:Ethylenes; D010940:Plant Proteins; C036216:ethylene
keywords: ACS; Apple; Ethylene biosynthesis; Ethylene responsive factor; Fruit