Functional insights into the late embryogenesis abundant (LEA) protein family from Dendrobium officinale (Orchidaceae) using an Escherichia coli system.

Hong Ling,Shunxing Guo,Xu Zeng

doi:10.1038/srep39693

Hong Ling, Shunxing Guo + Show 1 more

Open Access

https://doi.org/10.1038/srep39693

Copy DOI

Abstract

Late embryogenesis abundant (LEA) proteins, a diverse family, accumulate during seed desiccation in the later stages of embryogenesis. LEA proteins are associated with tolerance to abiotic stresses, such as drought, salinity and high or cold temperature. Here, we report the first comprehensive survey of the LEA gene family in Dendrobium officinale, an important and widely grown medicinal orchid in China. Based on phylogenetic relationships with the complete set of Arabidopsis and Oryza LEA proteins, 17 genes encoding D. officinale LEAs (DofLEAs) were identified and their deduced proteins were classified into seven groups. The motif composition of these deduced proteins was correlated with the gene structure found in each LEA group. Our results reveal the DofLEA genes are widely distributed and expressed in tissues. Additionally, 11 genes from different groups were introduced into Escherichia coli to assess the functions of DofLEAs. Expression of 6 and 7 DofLEAs in E. coli improved growth performance compared with the control under salt and heat stress, respectively. Based on qPCR data, all of these genes were up-regulated in various tissues following exposure to salt and heat stresses. Our results suggest that DofLEAs play an important role in responses to abiotic stress.

Highlights

In nature, abiotic stresses, such as drought, high temperature, salinity, cold, and heavy metal pollution, have a serious effect on plant growth and development[1], with drought, high temperature, and salinity being associated with water limitation
Phylogenetic analysis of the predicted proteins revealed that the 17 D. officinale LEAs (DofLEAs) genes could be classified into seven groups together with the Arabidopsis and Oryza Late embryogenesis abundant (LEA), including 4 LEA1, 3 LEA2, 2 LEA3, 4 LEA4, 1 LEA5, 2 dehydrin and 1 SMP protein-encoding genes (Fig. 1)
Analysis of physicochemical properties (Table 1) revealed that the DofLEA proteins have molecular weights ranging from 8.8 to 54.8 kDa, with the smallest proteins belonging to the LEA5 group (~8.8 kDa) and the largest proteins belonging to the LEA2 group (~54.8 kDa)

Summary

Introduction

Abiotic stresses, such as drought, high temperature, salinity, cold, and heavy metal pollution, have a serious effect on plant growth and development[1], with drought, high temperature, and salinity being associated with water limitation. D. officinale is a typical epiphytic orchid It grows compatibly on tree trunks in primeval forests or on damp rock of mountain climates at 500–1600 meters in warm and humid environments[17]. This orchid is influenced by abiotic stress, such as drought, high temperature, and salinity, causing an extremely low natural reproduction rate and slow growth in the wild[18,19,20]. We investigated the characteristics of the LEA gene family in D. officinale (DofLEA), including evolutionary relationships, putative functions, expression patterns in various tissues and responses to different abiotic stresses

Methods

Results

Conclusion