Genome-wide identification and expression analyses of genes involved in raffinose accumulation in sesame

Jun You,Xiurong Zhang,Komivi Dossa,Yanyan Wang,Donghua Li,Rong Zhou,Yujuan Zhang,Linhai Wang

doi:10.1038/s41598-018-22585-2

Jun You, Xiurong Zhang + Show 6 more

Open Access

https://doi.org/10.1038/s41598-018-22585-2

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Abstract

Sesame (Sesamum indicum L.) is an important oilseed crop. However, multiple abiotic stresses severely affect sesame growth and production. Raffinose family oligosaccharides (RFOs), such as raffinose and stachyose, play an important role in desiccation tolerance of plants and developing seeds. In the present study, three types of key enzymes, galactinol synthase (GolS), raffinose synthase (RafS) and stachyose synthase (StaS), responsible for the biosynthesis of RFOs were identified at the genome-wide scale in sesame. A total of 7 SiGolS and 15 SiRS genes were identified in the sesame genome. Transcriptome analyses showed that SiGolS and SiRS genes exhibited distinct expression profiles in different tissues and seed developmental stages. Comparative expression analyses under various abiotic stresses indicated that most of SiGolS and SiRS genes were significantly regulated by drought, osmotic, salt, and waterlogging stresses, but slightly affected by cold stress. The up-regulation of several SiGolS and SiRS genes by multiple abiotic stresses suggested their active implication in sesame abiotic stress responses. Taken together, these results shed light on the RFOs-mediated abiotic stress resistance in sesame and provide a useful framework for improving abiotic stress resistance of sesame through genetic engineering.

Highlights

Plant growth and productivity are greatly challenged by diverse environmental stresses, such as drought, waterlogging, or high-salinity, for their sessile nature
Raf and Sta are synthesized by stepwise addition of galactosyl units that are catalyzed by raffinose synthase (RafS, EC 2.4.1.82) and stachyose synthase (StaS, EC 2.4.1.67), respectively
Raffinose family oligosaccharides (RFOs), which accumulate during seed development and plant exposed to abiotic stresses, perform a critical function in desiccation tolerance of developing seeds and plants[6,7]

Summary

Introduction

Plant growth and productivity are greatly challenged by diverse environmental stresses, such as drought, waterlogging, or high-salinity, for their sessile nature To cope with these unfavorable conditions, plants have evolved a range of physiological and biochemical responses by activating a large number of stress-responsive genes and synthesizing various functional proteins through an intricate network of signaling cascades[1,2]. Biochemical and genetic analyses indicated that AtRS5 was the only RafS gene responsible for Raf accumulation in leaves under abiotic stresses[14]. Another RafS gene, AtRS4, encodes a seed specific multifunctional enzyme with RafS and high affinity StaS activity[15]

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