Transcriptome Analysis and Identification of Genes Associated with Starch Metabolism in Castanea henryi Seed (Fagaceae).

Bin Liu,Shuzhen Jiang,Xuedie Liu,Zhong-Jian Liu,Yuting Jiang,Ruqiang Lin,Hui Lian,Yuanfang Xiong,Shipin Chen,Qinmeng Zeng

doi:10.3390/ijms21041431

Abstract

Starch is the most important form of carbohydrate storage and is the major energy reserve in some seeds, especially Castanea henryi. Seed germination is the beginning of the plant’s life cycle, and starch metabolism is important for seed germination. As a complex metabolic pathway, the regulation of starch metabolism in C. henryi is still poorly understood. To explore the mechanism of starch metabolism during the germination of C. henryi, we conducted a comparative gene expression analysis at the transcriptional level using RNA-seq across four different germination stages, and analyzed the changes in the starch and soluble sugar contents. The results showed that the starch content increased in 0–10 days and decreased in 10–35 days, while the soluble sugar content continuously decreased in 0–30 days and increased in 30–35 days. We identified 49 candidate genes that may be associated with starch and sucrose metabolism. Three ADP-glucose pyrophosphorylase (AGPase) genes, two nucleotide pyrophosphatase/phosphodiesterases (NPPS) genes and three starch synthases (SS) genes may be related to starch accumulation. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to validate the expression levels of these genes. Our study combined transcriptome data with physiological and biochemical data, revealing potential candidate genes that affect starch metabolism during seed germination, and provides important data about starch metabolism and seed germination in seed plants.

Highlights

Seed germination is the basis of plant formation and is the period in the life of a plant with the highest metabolic activity
The physiological data showed that starch accumulated briefly during germination, while soluble sugar continuously decreased before the leaves began to grow
Transcriptome analysis identified 15 categories and 49 functional genes were associated with starch and sucrose metabolism pathways, and the expression levels of the granule-bound starch synthase (GBSS) gene (Che029279) revealed that GBSS may be the key regulatory factor of starch synthesis

Summary

Introduction

Seed germination is the basis of plant formation and is the period in the life of a plant with the highest metabolic activity. It is related to the subsequent growth and final yield of plants. During the period of germination, the metabolism of fats, proteins and carbohydrates provide energy for seedling growth [1,2,3]. Carbohydrates are an important source of cellular energy and are closely related to seed vigor and the germination process [4]. Starch is the most important carbohydrate reserves in plants and is mainly composed of amylopectin and amylose [5,6]. Amylose is essentially a linear molecule in which glucosyl monomers are joined via α-1,4 linkages, and amylopectin is composed of linked tandem clusters in which linear α-1,4-glucan chains are regularly branched via α-1,6-glucosidic linkages [7,8,9]

Methods

Discussion

Conclusion