Genome-wide identification and characterization of 14-3-3 gene family related to negative regulation of starch accumulation in storage root of Manihot esculenta

Abstract

The 14-3-3 protein family is a highly conservative member of the acid protein family and plays an important role in regulating a series of important biological activities and various signal transduction pathways. The role of 14-3-3 proteins in regulating starch accumulation still remains largely unknown. To investigate the properties of 14-3-3 proteins, the structures and functions involved in starch accumulation in storage roots were analyzed, and consequently, 16Me14-3-3genes were identified. Phylogenetic analysis revealed that Me14-3-3 family proteins are split into two groups (ε and non-ε). All Me14-3-3 proteins contain nine antiparallel α-helices. Me14-3-3s-GFP fusion protein was targeted exclusively to the nuclei and cytoplasm. In the early stage of starch accumulation in the storage root,Me14-3-3genes were highly expressed in high-starch cultivars, while in the late stage of starch accumulation,Me14-3-3genes were highly expressed in low-starch cultivars.Me14-3-3 I,II,V, andXVIhad relatively high expression levels in the storage roots. The transgenic evidence fromMe14-3-3IIoverexpression inArabidopsis thalianaand the virus-induced gene silencing (VIGS) in cassava leaves and storage roots suggest thatMe14-3-3IIis involved in the negative regulation of starch accumulation. This study provides a new insight to understand the molecular mechanisms of starch accumulation linked withMe14-3-3genes during cassava storage root development.