Transcriptomic analyses of gastrointestinal function in the "dwarf" and "medium" forms of Sthenoteuthis oualaniensis during sexual maturation.

Lulu Yan,Chao Zhao,Jun Zhang,Zuozhi Chen,Lihua Qiu,Peng Xu

doi:10.1371/journal.pone.0199053

Abstract

Sthenoteuthis oualaniensis (SA) is an important squid species in the South China Sea. Based on SA samples collected in 2016, SA was divided into the “dwarf” form (DF) and “medium” form (MF). To understand the changes in gastrointestinal function in SA during sexual maturation, we undertook transcriptomic analyses of the stomach and intestine tissues of the mature and immature DF and MF of SA using the deep-sequencing platform Illumina HiSeq™. We exploited a high-throughput method to delineate differentially expressed genes (DEGs) in the DF and MF of SA. A total of 135464 unigenes (68627 unigenes of the DG and 66837 unigenes of the MF) were generated. We identified 7965 and 4051 relative DEGs in the intestine and stomach tissues of the mature DF of SA compared with those of the immature DF of SA; and 22138 and 18460 DEGs in the intestine and stomach of the mature MF of SA compared with those of the immature MF of SA. Gastrointestinal function related to the metabolism of lipids, amino acids, glucose, and energy were changed in SA during sexual maturation. This work is the first to identify a set of genes associated with gastrointestinal function during sexual maturation in SA.

Highlights

Sthenoteuthis oualaniensis (SA; “purpleback flying squid”) is distributed widely along the equator throughout the Indo-Pacific region (40 ̊N to 40 ̊S) [1, 2]
A total of 599.38 million raw reads were produced from the dwarf form (DF) data set, whereas 1585.33 million raw reads were produced from the medium form (MF) data set (S1 Table)
An average length of 1194 bp and 95116 unigenes were longer than 500 bp

Summary

Introduction

Sthenoteuthis oualaniensis (SA; “purpleback flying squid”) is distributed widely along the equator throughout the Indo-Pacific region (40 ̊N to 40 ̊S) [1, 2]. SA is considered to be the most abundant large squid of commercial importance in the region [3]. Within this wide distribution, SA is known to have a wide ecological amplitude and complex population structure [1]. Two major forms of this species occur in the southern South China Sea based on their morphological characteristics: ‘dwarf’ and ‘medium’. [3, 4]

Methods

Results

Discussion

Conclusion