Transcriptome and Differential Expression Profiling Analysis of the Mechanism of Ca2+ Regulation in Peanut (Arachis hypogaea) Pod Development.

Sha Yang,Jialei Zhang,Na Sui,Feng Guo,Jianguo Wang,Lin Li,Xinguo Li,Shubo Wan,Jingjing Meng,Yun Geng

doi:10.3389/fpls.2017.01609

Abstract

Calcium not only serves as a necessary nutrient for plant growth but also acts as a ubiquitous central hub in a large number of signaling pathways. Free Ca2+ deficiency in the soil may cause early embryo abortion, which eventually led to abnormal development of peanut pod during the harvest season. To understand the mechanisms of Ca2+ regulation in pod development, transcriptome analysis of peanut gynophores and pods was performed by comparing the treatments between free Ca2+ sufficiency and free Ca2+ deficiency using Illumina HiSeq™ 2000. 9,903,082,800 nt bases are generated totally. After assembly, the average length of 102,819 unigenes is 999 nt, N50 is 1,782 nt. RNA-seq based gene expression profilings showed a large number of genes at the transcriptional level changed significantly between the aerial pegs and underground swelling pods under free Ca2+ sufficienct or deficiency treatments, respectively. Genes encoding key members of Ca2+ signaling transduction pathway, enzymes for hormone metabolism, cell division and growth, transcriptional factor as well as embryo development were highlighted. This information provides useful information for our further study. The results of digital gene expression (DGE) indicated that exogenous calcium might contribute to the development of peanut pod through its signal transduction pathway, meanwhile, promote the normal transition of the gynophores to the reproductive development.

Highlights

Peanut (Arachis hypogaea L.) is an economic crop that contributes 20% to the global oil production and 11% of the protein supply per year (Chen et al, 2014)
RNA-Seq and digital gene profiling were combined to investigate and compare differentially expressed genes (DEGs) between aerial gynophores and underground pods grown under free-Ca2+-sufficient or deficient Our objectives were to: (1) compare the DEGs of aerial gynophores between free Ca2+ sufficiency and free Ca2+ deficiency treatments, (2) identify candidate genes related to pod swelling affected by calcium, (3) find out the main regulatory pathways of calcium to promote pod development
We attempted to reveal the molecular mechanism of the effect of free calcium on the development of peanut pods using a RNA-seq approach

Summary

Introduction

Peanut (Arachis hypogaea L.) is an economic crop that contributes 20% to the global oil production and 11% of the protein supply per year (Chen et al, 2014). Ca2+ Regulates Peanut Pod Development to survive and reproduce (Arya et al, 2016). When gynophores are buried into the soil at 2–8 cm deep, the ovule swells to provide room for the embryo to grow. During this complex period, the peanut can directly absorb moisture, calcium, and other inorganic salts from the soil to maintain its reproductive development (Beringer and Taha, 1976). Calcium-deficient soil may result in the termination of pods expansion and eventually lead to embryo abortion. Peanuts will produce filled pods when sufficiently supplied with calcium (Jain et al, 2011). The development of peanut pod is extremely sensitive to calcium, and free-Ca2+ deficiency in the field will greatly reduce the yield of peanut

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Results

Conclusion