Cloning and comparative studies of seaweed trehalose-6-phosphate synthase genes

Characterization of Trehalose-6-phosphate Synthase and Trehalose-6-phosphate Phosphatase Genes and Analysis of its Differential Expression in Maize (Zea mays) Seedlings under Drought Stress

Maize is the most important crop around the world and it is highly sensitive to abiotic stress caused by drought, excessive salinity, and extreme temperature. In plants, trehalose has been widely studied for its role in plant adaptation to different abiotic stresses such as drought, high and low temperature, and osmotic stress. Thus, the aim of this work was to clone and characterize at molecular level the trehalose-6-phosphate synthase (TPS) and trehalose-6-phosphate phosphatase (TPP) genes from maize and to evaluate its differential expression in maize seedlings under drought stress. To carry out this, resistant and susceptible maize lines were subjected to drought stress during 72 h. Two full-length cDNAs of TPS and one of TPP were cloned and sequenced. Then, TPS and TPP amino acid sequences were aligned with their homologs from different species, showing highly conserved domains and the same catalytic sites. Relative expression of both genes was evaluated by RT-qPCR at different time points. The expression pattern showed significant induction after 0.5 h in resistant lines and after two to four hours in susceptible plants, showing their participation in drought stress response.

Cloning of a trehalose-6-phosphate synthase gene from Exopalaemon carinicauda and its expression response to bacteria challenge

Trehalose, a nonreducing disaccharide, is present in a wide variety of organisms and plays a key role in many organisms under different stress conditions. In the study, the full-length cDNA sequence encoding trehalose-6-phosphate synthase (EcTPS) was obtained from Exopalaemon carinicauda. The complete nucleotide sequence of EcTPS contained a 2532 bp open reading frame (ORF) encoding a putative protein of 843 amino acids. The domain architecture of the deduced EcTPS contained a glycol_transf_20 domain and a trehalose_PPase domain. EcTPS mRNA was predominantly expressed in the hepatopancreas. The expression of EcTPS in the prawns challenged with Vibrio parahaemolyticus and Aeromonas hydrophila changed in a time-dependent manner. The function of EcTPS was also studied by double-strand RNA interference. The results showed that the knock-down of EcTPS increased the mortality of the Vibrio-challenged group and Aeromonas-challenged group compared with the control group. The present study provides some new insight into the immune function of the trehalose-6-phosphate synthase in prawns.

Putative trehalose biosynthesis proteins function as differential floridoside-6-phosphate synthases to participate in the abiotic stress response in the red alga Pyropia haitanensis

BACKGROUND

The heteroside floridoside is a primary photosynthetic product that is known to contribute to osmotic acclimation in almost all orders of Rhodophyta. However, the encoding genes and enzymes responsible for the synthesis of floridoside and its isomeric form, L- or D-isofloridoside, are poorly studied.

RESULTS

Here, four putative trehalose-6-phosphate synthase (TPS) genes, designated as PhTPS1, PhTPS2, PhTPS3, and PhTPS4, were cloned and characterized from the red alga Pyropia haitanensis (Bangiophyceae). The deduced amino acid sequence is similar to the annotated TPS proteins of other organisms, especially the UDP-galactose substrate binding sites of PhTPS1, 2, which are highly conserved. Of these, PhTPS1, 4 are involved in the biosynthesis of floridoside and isofloridoside, with isofloridoside being the main product. PhTPS3 is an isofloridoside phosphate synthase, while PhTPS2 exhibits no activity. When challenged by desiccation, high temperature, and salt stress, PhTPS members were expressed to different degrees, but the responses to thermal stress and desiccation were stronger.

CONCLUSIONS

Thus, in P. haitanensis, PhTPSs encode the enzymatical activity of floridoside and isofloridoside phosphate synthase and are crucial for the abiotic stress defense response.

Genome-wide analysis of the Solanum tuberosum (potato) trehalose-6-phosphate synthase (TPS) gene family: evolution and differential expression during development and stress

BACKGROUND

Trehalose-6-phosphate synthase (TPS) serves important functions in plant desiccation tolerance and response to environmental stimuli. At present, a comprehensive analysis, i.e. functional classification, molecular evolution, and expression patterns of this gene family are still lacking in Solanum tuberosum (potato).

RESULTS

In this study, a comprehensive analysis of the TPS gene family was conducted in potato. A total of eight putative potato TPS genes (StTPSs) were identified by searching the latest potato genome sequence. The amino acid identity among eight StTPSs varied from 59.91 to 89.54%. Analysis of dN/dS ratios suggested that regions in the TPP (trehalose-6-phosphate phosphatase) domains evolved faster than the TPS domains. Although the sequence of the eight StTPSs showed high similarity (2571-2796 bp), their gene length is highly differentiated (3189-8406 bp). Many of the regulatory elements possibly related to phytohormones, abiotic stress and development were identified in different TPS genes. Based on the phylogenetic tree constructed using TPS genes of potato, and four other Solanaceae plants, TPS genes could be categorized into 6 distinct groups. Analysis revealed that purifying selection most likely played a major role during the evolution of this family. Amino acid changes detected in specific branches of the phylogenetic tree suggests relaxed constraints might have contributed to functional divergence among groups. Moreover, StTPSs were found to exhibit tissue and treatment specific expression patterns upon analysis of transcriptome data, and performing qRT-PCR.

CONCLUSIONS

This study provides a reference for genome-wide identification of the potato TPS gene family and sets a framework for further functional studies of this important gene family in development and stress response.

A trehalose-6-phosphate synthase gene from Saccharina japonica (Laminariales, Phaeophyceae)

The full-length cDNA sequence of a trehalose-6-phosphate synthase gene from Saccharina japonica (designated as SjaTPS) (Accession: KC578568) was isolated based on homologous cloning and RACE-PCR. It was 4,127 bp, with 320 bp 5'-UTR, 21 bp 3'-UTR, and open reading frame (ORF) of 3,786 bp. The deduced 1,261 amino acids characterized with predicted molecular weight of 137.84 kDa and theoretical isoelectric point of 7.12. The SjaTPS had one N-terminal CBM20 (family 20 carbohydrate-binding module) domain, one TPS domain (trehalose-6-phosphate synthase) in the middle region and a single TPP (trehalose-6-phosphate phosphatase) domain near the C-terminus. Structural analysis suggested that the SjaTPS putatively functioned as trehalose-6-phosphate synthase, and might be related to laminaran metabolism in S. japonica. Homology analysis indicated that the SjaTPS shared 49-70 % similarities with the 13 known TPS sequences of other algae; only 55 % amino acid similarities were detected between SjaTPS and the previously reported TPS sequence of S. japonica (Accession: DQ666325). Phylogenetic analysis revealed close affinity between SjaTPS and TPS of brown alga Ectocarpus siliculosus (Accession: CBJ29609). Transcriptional analysis showed that desiccation greatly enhanced SjaTPS expression and the maximum appeared at 3 h, which was about 300-fold compared to that of the start, implied that SjaTPS was involved with drought adaption in kelp. In vitro expression of SjaTPS showed that one distinct band existed at ~115 kDa, and western blot detection proved that it was positive to the anti-His antibody with high specificity. Our results increased the knowledge of trehalose-6-phosphate synthase properties in S. japonica and also important for better understanding the role trehalose plays in kelp abiotic tolerance for adaption to the sublittoral habitats.

Cloning of TPS gene from eelgrass species Zostera marina and its functional identification by genetic transformation in rice

The full-length cDNA sequence (2613 bp) of the trehalose-6-phosphate synthase (TPS) gene of eelgrass Zostera marina (ZmTPS) was identified and cloned. Z. marina is a kind of seed-plant growing in sea water during its whole life history. The open reading frame (ORF) region of ZmTPS gene encodes a protein of 870 amino acid residues and a stop codon. The corresponding genomic DNA sequence is 3770 bp in length, which contains 3 exons and 2 introns. The ZmTPS gene was transformed into rice variety ZH11 via Agrobacterium-mediated transformation method. After antibiotic screening, molecular characterization, salt-tolerance and trehalose content determinations, two transgenic lines resistant to 150 mM NaCL solutions were screened. Our study results indicated that the ZmTPS gene was integrated into the genomic DNA of the two transgenic rice lines and could be expressed well. Moreover, the detection of the transformed ZmTPS gene in the progenies of the two transgenic lines was performed from T1 to T4 generations; and results suggested that the transformed ZmTPS gene can be transmitted from parent to the progeny in transgenic rice.

A trehalose-6-phosphate synthase gene from Chinese shrimp, Fenneropenaeus chinensis

Trehalose is an important disaccharide and plays a key role in many organisms under different stress conditions. In the study, a gene (FcTPS) encoded trehalose-6-phosphate synthase was reported from Chinese shrimp, Fenneropenaeus chinensis. The full-length cDNA of FcTPS is 3,281 bp including a poly A-tail of 20 bp, encoding a putative protein of 844 amino acids. The predicted protein contains a glycol_transf_20 domain and a trehalose_PPase domain. Genomic structure of FcTPS is composed of three exons with 192, 157 and 2,912 bp and two introns with 1,057 and 568 bp. In the second intron, four different SSRs are found. Transcripts of FcTPS gene are constitutively expressed in various tissues, with strongest level in hepatopancreas. After the shrimp were challenged with WSSV or Vibrio and the expression of FcTPS in hepatopancreas were analyzed using real-time PCR, the result showed that FcTPS transcript was down-regulated significantly in response to the challenge of Vibro at the early of 5 h post-challenge and then up-regulated significantly at 14 h. In addition, the expression of FcTPS showed the same result after the shrimp were challenged with WSSV. These results provide some new information about the tissue distribution, expression profiles and potential function of the trehalose-6-phosphate synthase in shrimp.