the aintegumenta genes, mdant1 and mdant2, are associated with the regulation of cell production during fruit growth in apple (malus × domestica borkh.)mdant1和mdant2 aintegumenta基因,与细胞生产的规定在苹果果实生长期间(马吕斯×有borkh)。.pdf

Dash and Malladi BMC Plant Biology 2012, 12:98 /1471-2229/12/98 RESEARCH ARTICLE Open Access The AINTEGUMENTA genes, MdANT1 and MdANT2, are associated with the regulation of cell production during fruit growth in apple (Malus × domestica Borkh.) * Madhumita Dash and Anish Malladi Abstract Background: Fruit growth in apple (Malus × domestica Borkh.) is mediated by cell production and expansion. Genes involved in regulating these processes and thereby fruit growth, are not well characterized. We hypothesized that the apple homolog(s) of AINTEGUMENTA (ANT), an APETALA2–repeat containing transcription factor, regulates cell production during fruit growth in apple. Results: Two ANT genes, MdANT1 and MdANT2, were isolated from apple and their expression was studied during multiple stages of fruit development. MdANT1 and MdANT2 expression was high during early fruit growth coincident with the period of cell production, rapidly declined during exit from cell production, and remained low during the rest of fruit development. The effects of increase in carbohydrate availability during fruit growth were characterized. Increase in carbohydrate availability enhanced fruit growth largely through an increase in cell production. Expression of MdANT1 and MdANT2 increased sharply by up to around 5-fold in response to an increase in carbohydrate availability. Expression of the ANT genes was compared across two apple genotypes, ‘Gala’ and ‘Golden Delicious Smoothee’ (GS), which differ in the extent of fruit growth, largely due to differences in cell production. In comparison to ‘Gala’, the larger fruit-size genotype, GS, displayed higher levels and a longer duration of MdANT1 and MdANT2 expression. Expression of the ANTs and cell cycle genes in the fruit core and cortex tissues isolated