Genome-Wide Identification and Expression Profiling of the PDI Gene Family Reveals Their Probable Involvement in Abiotic Stress Tolerance in Tomato (Solanum Lycopersicum L.).

Antt Htet Wai,A B M Mahbub Morshed Khan,Do Jin Lee,Ujjal Kumar Nath,Muhammad Waseem,Chang Kil Kim,Sang Tae Kim,Mi Young Chung

doi:10.3390/genes12010023

Abstract

Protein disulfide isomerases (PDI) and PDI-like proteins catalyze the formation and isomerization of protein disulfide bonds in the endoplasmic reticulum and prevent the buildup of misfolded proteins under abiotic stress conditions. In the present study, we conducted the first comprehensive genome-wide exploration of the PDI gene family in tomato (Solanum lycopersicum L.). We identified 19 tomato PDI genes that were unevenly distributed on 8 of the 12 tomato chromosomes, with segmental duplications detected for 3 paralogous gene pairs. Expression profiling of the PDI genes revealed that most of them were differentially expressed across different organs and developmental stages of the fruit. Furthermore, most of the PDI genes were highly induced by heat, salt, and abscisic acid (ABA) treatments, while relatively few of the genes were induced by cold and nutrient and water deficit (NWD) stresses. The predominant expression of SlPDI1-1, SlPDI1-3, SlPDI1-4, SlPDI2-1, SlPDI4-1, and SlPDI5-1 in response to abiotic stress and ABA treatment suggested they play regulatory roles in abiotic stress tolerance in tomato in an ABA-dependent manner. Our results provide new insight into the structure and function of PDI genes and will be helpful for the selection of candidate genes involved in fruit development and abiotic stress tolerance in tomato.

Highlights

Protein disulfide isomerases (PDIs) are endoplasmic reticulum (ER)-resident thiodisulfide oxidoreductases whose primary function is to catalyze the formation, reduction, and rearrangement of disulfide bonds in newly synthesized proteins or target proteins
We identified 19 non-redundant tomato genes that encoded proteins with similarity to PDI, which we designated SlPDI1-1-SlPDI11-3
PDI proteins participate in plant development and stress tolerance by ensuring the proper folding of misfolded or denatured proteins

Summary

Introduction

Protein disulfide isomerases (PDIs) are endoplasmic reticulum (ER)-resident thiodisulfide oxidoreductases whose primary function is to catalyze the formation, reduction, and rearrangement of disulfide bonds in newly synthesized proteins or target proteins. The PDI gene family encodes PDI and PDI-like (PDIL) proteins that contain at least one redox-active thioredoxin domain responsible for the alteration of disulfide bonds, a feature that distinguishes the PDI family from other families in the thioredoxoin superfamily, such as glutaredoxins, ferredoxins, and peroxidoxins [6,7,8] They are typically located in the ER, PDIs have been found in other cellular locations, such as the nucleus, mitochondria, the cytoplasm, and the extracellular environment [9,10,11,12,13]. Many PDI proteins have been well investigated, in mammals, including endoplasmic reticulum resident protein 57 (ERp57), PDIp, PDI-P5, ERp72, PDI-RELATED (PDIR), and PDI with D-domain (PDI-D) These proteins act as redox catalysts and isomerases in addition to having other functions, such as peptide binding, cell adhesion, and chaperone activities [14,15]. The c domain, located in the C terminal region, is enriched in acidic residues characteristic of calcium-binding proteins and usually ends with a KDEL peptide motif critical for ER retention [19,20]

Methods

Results

Discussion

Conclusion