Functional characterization of a starch synthesis-related gene AmAGP in Amorphophallus muelleri

Abstract

Amorphophallus has attracted tremendous interest because of its high contents of glucomannan and starch. Very few genes regulating glucomannan and starch were reported inAmorphophallus. In this study, an ADP-glucose pyrophosphorylase (AGP) gene that plays a significant role in plant starch synthesis was cloned fromAmorphophallus muelleri. It was shown that it encoded a predicted protein containing a conserved plant ADP-Glucose-PP repeat domain and seven potential ligand-binding sites. The real-time quantitative PCR showed thatAmAGPwas most abundant in tubers, and it was positively correlated with starch content. Additionally, its influencers about temperature and exogenous plant hormone were also discussed, showing thatAmAGPexpressed highly in tubers under treatments using 25 degrees C and IAA. Furthermore, starch content was closely related toAmAGPexpression level, suggesting thatAmAGPwas involved in the regulation of starch synthesis inA. muelleri. Therefore, identifying the sequence ofAmAGPand its expression pattern during tuber enlarging and the changes of its transcript levels in response to temperature and plant hormones would contribute to a better understanding of starch synthesis, and also providing a reference information for future preferable breeding for obtaining more starch or more glucomannan inAmorphophallus.