GIBBERELLIN INSENSITIVE DWARF1 Plays an Important Role in the Growth Regulation of Dwarf Apple Rootstocks

Abstract

<jats:p>Dwarfing rootstocks can improve the plant architecture of apple trees and increase production. Gibberellins (GAs) are crucial for plant growth and dwarfing traits. The receptor, GIBBERELLIN INSENSITIVE DWARF1 (GID1), plays an important role in the regulation pathway. However, the growth regulatory mechanism of GID1 in dwarf apple rootstock seedlings is not clear. In this study, we selected dwarf apple rootstock ‘SH6’ and its cross parents as materials to clone the GA receptor gene <jats:italic>GID1c</jats:italic>. There were two different sites in the alpha/beta hydrolase domain. The expression of <jats:italic>GID1c</jats:italic> in ‘SH6’ was lower than that in <jats:italic>Malus domestica</jats:italic> cv. Ralls Janet, with the decrease of GA content. We further conducted GA<jats:sub>3</jats:sub> treatment and overexpression of <jats:italic>GID1c</jats:italic> in tissue culture seedlings of ‘SH6’, and the results showed that the expression of <jats:italic>GID1c</jats:italic> and biosynthesis genes increased and promoted the accumulation of hormone contents, which ultimately regulates the growth of ‘SH6’ dwarf apple rootstock seedlings. Our results suggest that GID1c may affect the plant architecture and dwarf traits of dwarfing rootstock and accelerate its application in orchards.</jats:p>