Identification and expression analysis of the GDSL esterase/lipase family genes, and the characterization of SaGLIP8 in Sedum alfredii Hance under cadmium stress

He Li; Xiaojiao Han; Wenmin Qiu; Dong Xu; Ying Wang; Miao Yu; Xianqi Hu; Renying Zhuo

doi:10.7717/peerj.6741

Identification and expression analysis of the GDSL esterase/lipase family genes, and the characterization of SaGLIP8 in Sedum alfredii Hance under cadmium stress

PeerJ. 2019 Apr 16:7:e6741. doi: 10.7717/peerj.6741. eCollection 2019.

Authors

He Li^#^{1

2

3}, Xiaojiao Han^#^{2

3}, Wenmin Qiu^{2

3}, Dong Xu^{2

3}, Ying Wang^{2

3}, Miao Yu^{2

3}, Xianqi Hu¹, Renying Zhuo^{2

3}

Affiliations

¹ College of Plant Protection, Yunnan Agricultural University, Kunming, Yunnan, China.
² State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing, China.
³ Key Laboratory of Tree Breeding of Zhejiang Province, The Research Institute of Subtropical of Forestry, Chinese Academy of Forestry, Hangzhou, Zhejiang, China.

^# Contributed equally.

Abstract

Background: The herb Sedum alfredii (S. alfredii) Hance is a hyperaccumulator of heavy metals (cadmium (Cd), zinc (Zn) and lead (Pb)); therefore, it could be a candidate plant for efficient phytoremediation. The GDSL esterase/lipase protein (GELP) family plays important roles in plant defense and growth. Although the GELP family members in a variety of plants have been cloned and analyzed, there are limited studies on the family's responses to heavy metal-stress conditions.

Methods: Multiple sequence alignments and phylogenetic analyses were performed according to the criteria described. A WGCNA was used to construct co-expression regulatory networks. The roots of S. alfredii seedlings were treated with 100 µM CdCl₂ for qRT-PCR to analyze expression levels in different tissues. SaGLIP8 was transformed into the Cd sensitive mutant strain yeast Δycf1 to investigate its role in resistance and accumulation to Cd.

Results: We analyzed GELP family members from genomic data of S. alfredii. A phylogenetic tree divided the 80 identified family members into three clades. The promoters of the 80 genes contained certain elements related to abiotic stress, such as TC-rich repeats (defense and stress responsiveness), heat shock elements (heat stress) and MYB-binding sites (drought-inducibility). In addition, 66 members had tissue-specific expression patterns and significant responses to Cd stress. In total, 13 hub genes were obtained, based on an existing S. alfredii transcriptome database, that control 459 edge genes, which were classified into five classes of functions in a co-expression subnetwork: cell wall and defense function, lipid and esterase, stress and tolerance, transport and transcription factor activity. Among the hub genes, Sa13F.102 (SaGLIP8), with a high expression level in all tissues, could increase Cd tolerance and accumulation in yeast when overexpressed.

Conclusion: Based on genomic data of S. alfredii, we conducted phylogenetic analyses, as well as conserved domain, motif and expression profiling of the GELP family under Cd-stress conditions. SaGLIP8 could increase Cd tolerance and accumulation in yeast. These results indicated the roles of GELPs in plant responses to heavy metal exposure and provides a theoretical basis for further studies of the SaGELP family's functions.

Keywords: Cadmium stress; GDSL esterase/lipase proteins (GELPs); SaGLIP8; Sedum alfredii Hance.

Grants and funding

This work was supported by the National Nonprofit Institute Research Grant of Chinese Academy of Forestry (No. CAFYBB2016SY008), the National Natural Science Foundation of China (No. 31872168), the Zhejiang Science and Technology Major Program on Agricultural New Variety Breeding (No. 2016C02056-1) and the Agricultural Projects of Public Scientific and Technology Research Zhejiang Province (No. 2016C32G3030016). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.