Dataset Information

Dehydroascorbate reductase and monodehydroascorbate reductase activities of two metallothionein-like proteins from sweet potato (Ipomoea batatas [L.] Lam. 'Tainong 57') storage roots.

ABSTRACT: BACKGROUND:Metallothionein (MT) is a group of proteins with low molecular masses and high cysteine contents, and it is classified into different types, which generally contains two domains with typical amino acid sequences. RESULTS:In this report, two full-length cDNAs (MT-1 and MT-II) encoding MT-like proteins were isolated from the roots of sweet potato (Ipomoea batatas [L.] Lam. 'Tainong 57'). Their open reading frames contained 642 and 519 nucleotides (66 and 81 amino acids) for MT-1 and MT-II, respectively, and exhibited a relatively low amino acid sequence similarity. On the basis of the amino acid sequence similarity and conserved residues, it is suggested that MT-I is a member of the plant MT Type-I family, and MT-II is a member of the plant MT Type-II family. The corresponding mRNA levels of MT-1 and MT-II were the highest found in the storage roots. Recombinant MT-1 and MT-II protein overproduced in E. coli (M15) was purified by Ni2+-chelated affinity chromatography. MT-1 and MT-II reduced dehydroascorbate (DHA) in the presence of glutathione (GSH) to regenerate L-ascorbic acid (AsA). However, without GSH, MT-1 and MT-II has very low DHA reductase activity. And AsA was oxidized by AsA oxidase to generate monodehydroascorbate (MDA) free radical. MDA was also reduced by MT-1 and MT-II to AsA in the presence of NADH mimicking the MDA reductase catalyzed reaction. CONCLUSIONS:These data suggest that MT-1 and MT-II have both DHA reductase and MDA reductase activities. MT-1 and MT-II are apparently the first reported plant MTs exhibiting both DHA and MDA activities in vitro.

SUBMITTER: Huang GJ

PROVIDER: S-EPMC5430376 | biostudies-literature | 2013 Dec

REPOSITORIES: biostudies-literature

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Dehydroascorbate reductase and monodehydroascorbate reductase activities of two metallothionein-like proteins from sweet potato (Ipomoea batatas [L.] Lam. 'Tainong 57') storage roots.

Huang Guan-Jhong GJ Deng Jeng-Shyan JS Chen Hsien-Jung HJ Huang Shyh-Shyun SS Shih Chun-Ching CC Lin Yaw-Huei YH

Botanical studies 20130821 1

<h4>Background</h4>Metallothionein (MT) is a group of proteins with low molecular masses and high cysteine contents, and it is classified into different types, which generally contains two domains with typical amino acid sequences.<h4>Results</h4>In this report, two full-length cDNAs (MT-1 and MT-II) encoding MT-like proteins were isolated from the roots of sweet potato (Ipomoea batatas [L.] Lam. 'Tainong 57'). Their open reading frames contained 642 and 519 nucleotides (66 and 81 amino acids) f ...[more]

PMID: 28510854

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Project description:BACKGROUND: Sweet potato (Ipomoea batatas L. [Lam.]) ranks among the top six most important food crops in the world. It is widely grown throughout the world with high and stable yield, strong adaptability, rich nutrient content, and multiple uses. However, little is known about the molecular biology of this important non-model organism due to lack of genomic resources. Hence, studies based on high-throughput sequencing technologies are needed to get a comprehensive and integrated genomic resource and better understanding of gene expression patterns in different tissues and at various developmental stages. METHODOLOGY/PRINCIPAL FINDINGS: Illumina paired-end (PE) RNA-Sequencing was performed, and generated 48.7 million of 75 bp PE reads. These reads were de novo assembled into 128,052 transcripts (? 100 bp), which correspond to 41.1 million base pairs, by using a combined assembly strategy. Transcripts were annotated by Blast2GO and 51,763 transcripts got BLASTX hits, in which 39,677 transcripts have GO terms and 14,117 have ECs that are associated with 147 KEGG pathways. Furthermore, transcriptome differences of seven tissues were analyzed by using Illumina digital gene expression (DGE) tag profiling and numerous differentially and specifically expressed transcripts were identified. Moreover, the expression characteristics of genes involved in viral genomes, starch metabolism and potential stress tolerance and insect resistance were also identified. CONCLUSIONS/SIGNIFICANCE: The combined de novo transcriptome assembly strategy can be applied to other organisms whose reference genomes are not available. The data provided here represent the most comprehensive and integrated genomic resources for cloning and identifying genes of interest in sweet potato. Characterization of sweet potato transcriptome provides an effective tool for better understanding the molecular mechanisms of cellular processes including development of leaves and storage roots, tissue-specific gene expression, potential biotic and abiotic stress response in sweet potato.

Project description:BACKGROUND AND AIMS:The tuberization mechanism of sweet potato (Ipomoea batatas) has long been studied using various approaches. Morphological data have revealed that the tuberizing events result from the activation of the cambium, followed by cell proliferation. However, uncertainties still remain regarding the regulators participating in this signal-transduction pathway. An attempt was made to characterize the role of one MADS-box transcription factor, which was preferentially expressed in sweet potato roots at the early tuberization stage. METHODS:A differential expression level of IbMADS1 (Ipomoea batatas MADS-box 1) was detected temporally and spatially in sweet potato tissues. IbMADS1 responses to tuberization-related hormones were assessed. In order to identify the evolutionary significance, the expression pattern of IbMADS1 was surveyed in two tuber-deficient Ipomoea relatives, I. leucantha and I. trifida, and compared with sweet potato. In functional analyses, potato (Solanum tuberosum) was employed as a heterologous model. The resulting tuber morphogenesis was examined anatomically in order to address the physiological function of IbMADS1, which should act similarly in sweet potato. KEY RESULTS:IbMADS1 was preferentially expressed as tuberous root development proceeded. Its expression was inducible by tuberization-related hormones, such as jasmonic acid and cytokinins. In situ hybridization data showed that IbMADS1 transcripts were specifically distributed around immature meristematic cells within the stele and lateral root primordia. Inter-species examination indicated that IbMADS1 expression was relatively active in sweet potato roots, but undetectable in tuber-deficient Ipomoea species. IbMADS1-transformed potatoes exhibited tuber morphogenesis in the fibrous roots. The partial swellings along fibrous roots were mainly due to anomalous proliferation and differentiation in the xylem. CONCLUSIONS:Based on this study, it is proposed that IbMADS1 is an important integrator at the initiation of tuberization. As a result, the initiation and development of tuberous roots seems to be well regulated by a network involving a MADS-box gene in which such hormones as jasmonic acid and cytokinins may act as trigger factors.

Dataset Information

Dehydroascorbate reductase and monodehydroascorbate reductase activities of two metallothionein-like proteins from sweet potato (Ipomoea batatas [L.] Lam. 'Tainong 57') storage roots.

Publications

Dehydroascorbate reductase and monodehydroascorbate reductase activities of two metallothionein-like proteins from sweet potato (Ipomoea batatas [L.] Lam. 'Tainong 57') storage roots.

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