Genome-Wide Analysis of nsLTP Gene Family and Identification of SiLTPs Contributing to High Oil Accumulation in Sesame (Sesamum indicum L.).

Shengnan Song,Lisong Shi,Chen Sheng,Linhai Wang,Komivi Dossa,Wangyi Zhou,Senouwa Segla Koffi Dossou,Jun You,Xiurong Zhang

doi:10.3390/ijms22105291

Abstract

The biosynthesis and storage of lipids in oil crop seeds involve many gene families, such as nonspecific lipid-transfer proteins (nsLTPs). nsLTPs are cysteine-rich small basic proteins essential for plant development and survival. However, in sesame, information related to nsLTPs was limited. Thus, the objectives of this study were to identify the Sesamum indicum nsLTPs (SiLTPs) and reveal their potential role in oil accumulation in sesame seeds. Genome-wide analysis revealed 52 SiLTPs, nonrandomly distributed on 10 chromosomes in the sesame variety Zhongzhi 13. Following recent classification methods, the SiLTPs were divided into nine types, among which types I and XI were the dominants. We found that the SiLTPs could interact with several transcription factors, including APETALA2 (AP2), DNA binding with one finger (Dof), etc. Transcriptome analysis showed a tissue-specific expression of some SiLTP genes. By integrating the SiLTPs expression profiles and the weighted gene co-expression network analysis (WGCNA) results of two contrasting oil content sesame varieties, we identified SiLTPI.23 and SiLTPI.28 as the candidate genes for high oil content in sesame seeds. The presumed functions of the candidate gene were validated through overexpression of SiLTPI.23 in Arabidopsis thaliana. These findings expand our knowledge on nsLTPs in sesame and provide resources for functional studies and genetic improvement of oil content in sesame seeds.

Highlights

Sesame seed oil is one of the most appreciated oils worldwide due to its quality values and the physiological functions of its specific lignans [1]
C22:1 FA increased, while the content of C16:0 FA, C18:1 FA and C18:2 FA decreased in the OE lines (Figure 6c). These findings indicated the overexpression of SiLTPI.23 in Arabidopsis increased the oil content in Arabidopsis seeds, regulated the ratio of fatty acids, and did not cause fatty acid modifications
SiLTPI.23 and SiLTPI.28 as the candidate genes associated with high oil content in sesame

Summary

Introduction

Sesame seed oil is one of the most appreciated oils worldwide due to its quality values and the physiological functions of its specific lignans [1]. Genome-wide association study (GWAS) and transcriptome analysis revealed that many classes of genes, including nonspecific lipid transfer proteins (nsLTPs), are involved in oil biosynthesis, regulation and accumulation in sesame seeds [2,3]. Plant nsLTPs represent small basic secreted proteins, possessing the lipid-binding ability and participating in lipid shifting [5,6]. They are often appointed nonspecific LTPs (nsLTPs) due to their faculty to bind and transfer various phospholipids, acyl groups and fatty acids between biological membranes [7,8,9]. They are often appointed nonspecific LTPs (nsLTPs) due to their faculty to bind and transfer various phospholipids, acyl groups and fatty acids between biological membranes [7,8,9]. nsLTPs were first reported in vitro in

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