ITRAQ-Based Quantitative Proteomic Analysis of Embryogenic and Non-embryogenic Calli Derived from a Maize (Zea mays L.) Inbred Line Y423.

Beibei Liu,Shipeng Li,Junyou Han,Yaping Yuan,Shengzhong Su,Hongkui Liu,Ying Wu,Xiaohui Shan

doi:10.3390/ijms19124004

Abstract

Somatic embryos (SE) have potential to rapidly form a whole plant. Generally, SE is thought to be derived from embryogenic calli (EC). However, in maize, not only embryogenic calli (EC, can generate SE) but also nonembryogenic calli (NEC, can’t generate SE) can be induced from immature embryos. In order to understand the differences between EC and NEC and the mechanism of EC, which can easily form SE in maize, differential abundance protein species (DAPS) of EC and NEC from the maize inbred line Y423 were identified by using the isobaric tags for relative and absolute quantification (iTRAQ) proteomic technology. We identified 632 DAPS in EC compared with NEC. The results of bioinformatics analysis showed that EC development might be related to accumulation of pyruvate caused by the DAPS detected in some pathways, such as starch and sucrose metabolism, glycolysis/gluconeogenesis, tricarboxylic acid (TCA) cycle, fatty acid metabolism and phenylpropanoid biosynthesis. Based on the differentially accumulated proteins in EC and NEC, a series of DAPS related with pyruvate biosynthesis and suppression of acetyl-CoA might be responsible for the differences between EC and NEC cells. Furthermore, we speculate that the decreased abundance of enzymes/proteins involved in phenylpropanoid biosynthesis pathway in the EC cells results in reducing of lignin substances, which might affect the maize callus morphology.

Highlights

Maize is one of the most important cereal crops in the world
We have identified a new receptor of an elite maize (Z. mays L.) inbred line for genetic transformation which displaying high efficiency via intact somatic embryogenesis [8,9]
The accumulated abundance of the proteins mentioned above could promote the synthesis of D-glucose, which is an important source of pyruvate. These results suggested that the high expression of glucose-producing related enzymes in starch and sucrose metabolism might indirectly affect the metabolism of pyruvate from its source

Summary

Introduction

Maize production is directly related to the agricultural economy and farmers’ income [1]. With the development of molecular breeding and transgenic technology, more and more new genetically modified (GM) maize varieties have been developed and widely cultivated, which has made a tremendous contribution to raising farmers’ incomes and ensuring food security (http://www.isaaa.org/resources/publications/briefs/). Somatic embryos (SE), which have the potential to rapidly form a whole plant, have been widely used to propagate transgenic organisms and to obtain genetically modified plants [5]. Understanding the mechanism of maize SE development is a key issue to be solved [5]. The first issue is to find the key regulatory pathways that could induce the development of embryogenic callus (EC, can generate SE) rather than nonembryogenic callus (NEC, can’t generate SE) during somatic embryogenesis

Objectives

Results

Conclusion