[Show abstract][Hide abstract] ABSTRACT: In this study, a full-length cDNA of the acyl-ACP thioesterase, AhFatA, was cloned from developing seeds of Arachis hypogaea L. by 3'-RACE. Sequence analysis showed that the open reading frame encodes a peptide of 372 amino acids and has 50-70% identity with FatA from other plants. Real-time quantitative PCR analysis revealed that AhFatA was expressed in all tissues of A. hypogaea L., but most strongly in the immature seeds harvested at 60 days after pegging. Heterologous expression of AhFatA in Escherichia coli affected bacterial growth and changed the fatty acid profiles of the membrane lipid, resulting in directed accumulation towards palmitoleic acid and oleic acid. These results indicate that AhFatA is at least partially responsible for determining the high palmitoleic acid and oleic acid composition of E. coli.
BioMed Research International 01/2012; 2012:652579. · 2.88 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: NAC transcription factors are a family of functionally diverse proteins. They are unique to plants and play an important role in regulation of plant growth and development, hormone regulation and responses to various stresses. A cDNA encoding the NAC-like gene homologue was isolated from maize (Zea mays L.) by RT-PCR and designated ZmNAC1 (GenBank Accession No. EU224278). Sequence analysis showed that cDNA of ZmNAC1 was 1,029 bp long and contained a single open reading frame (ORF, 26 to approximately 907 bp). The predicted ZmNAC1 protein has 293 amino acids with an estimated molecular mass of 32.3 kDa and an isoelectric point of 8.65. RT-PCR analysis showed that the expression of ZmNAC1 was induced by low temperature, PEG, salt, and ABA, respectively. These results suggest that ZmNAC1 may play important roles in biotic and abiotic resistance pathways. This is the first NAC-like gene reported in maize.
[Show abstract][Hide abstract] ABSTRACT: α-Linolenic acid (ALA, C 18:3Δ9,12,15) has many important biological functions. ω-3 Fatty acid desaturase (FAD3), existing in cytosolic and plastidic compartments
of higher plants, catalyzes linoleic acid (LA) desaturation to produce ALA. GmFAD3A-2 and GmFAD3C genes encoding cytosolic FAD3 from Qihuang 29 soybean were cloned and inserted into p416 vector and expressed in K601 yeast
strain. Gas chromatography showed that the transformed yeast strains could produce ALA. The ALA accumulation levels for the
strains transformed with GmFAD3A-2 or GmFAD3C genes were 0.77 ± 0.1 and 4.13 ± 0.4% of total fatty acids, respectively, while, as compared with that of the control, the
contents of LA decreased from 14.34 ± 0.8 to 10.93 ± 0.0 and 7.85 ± 0.1%, respectively, implying that the GmFAD3C enzyme is
more vigorous or stable, than GmFAD3A-2.
[Show abstract][Hide abstract] ABSTRACT: An efficient organogenesis and micropropagation system was developed for in vitro plant regeneration of multiple cultivars of peanut (Arachis hypogaea). The system was used to regenerate plants from nine cultivars: Luhua no. 9, Luhua no. 13, Luhua no. 14, Fenghua no. 1, Fenghua
no. 3, Fenghua no. 5, Huayu no. 23, Qinglan no. 2, and Baisha 1016. Epicotyl and embryo axis explants were cultured on Murashige
and Skoog (MS) basal medium supplemented with 33.29–44.39μM 6-benzyladenine (BAP) and 2.15–4.30μM α-naphthaleneacetic acid
(NAA). The highest rate of shoot formation was observed in epicotyl explants taken from 4-d-old seedlings (5.1 ± 1.4 shoots
per explant). Optimum shoot development was observed in explants cultured on MS medium containing 4.48μM BAP and 2.89 or
5.78μM gibberellin (GA3). Well-developed shoots (3–5cm high) formed roots after 2wk on MS medium containing 0–2.69μM NAA. We observed that all
multiple shoots formed at the site of epicotyl incision and at the upper end of each section, indicating physiological polarity
of shoot formation. The maximum shoot induction rate for Luhua no. 9, Luhua no. 13, Luhua no. 14, Fenghua no. 1, Fenghua no.
3, Fenghua no. 5, Huayu no. 23, Qinglan no. 2, and Baisha 1016 was 60.0%, 83.3%, 80.7%, 91.5%, 86.0%, 59.7%, 75.0%, 67.3%,
and 72.7%, respectively. This regeneration system will play a vital role in achieving the genetic improvement of Chinese peanut.
[Show abstract][Hide abstract] ABSTRACT: Seven cDNA sequences putatively encoding metallothionein (MT) proteins were isolated from peanut (Arachis hypogaea L.). We analyzed the sequences of the deduced amino acids and characterized one of these genes, AhMT2a. Northern blot analysis indicates that the accumulation of AhMT2a mRNA was found in stems, young roots, and young leaves, and AhMT2a mRNA levels were up-regulated by cadmium, copper, ABA, H2O2, and heat shock. The metal-binding properties of the recombinant protein expressed in E. coli was investigated, and the results show that bacteria harboring AhMT2a exhibited increased tolerance to cadmium, copper, and lead, and the metal accumulation was also higher than the controls.
Taken together, our results suggest that the AhMT2a protein might function in both detoxification of heavy metals and scavenging
of reactive oxygen species in peanut.
[Show abstract][Hide abstract] ABSTRACT: Metallothioneins, which widely distribute in eukaryotic and prokaryotic organisms, are a class of cystein-rich and heavy metal-binding proteins with low molecular weights. Many genes encoding plant metallothioneins have been cloned in the past years. There is certain progress on the expression patterns, tissue specificities and structures of these genes such as the loci of promoters and introns in chromosomes, however, their exact functions remain unknown. The expressions of many plant metallothionein genes under environmental stresses suggested that they may function in both metal chaperoning and scavenging of reactive oxygen species with their large number of cysteine residues to protect plants from oxidative damage. The classification, characteristics, gene structure of plant metallothioneins, and recent advances in heavy metal detoxification are summarized in detail.
[Show abstract][Hide abstract] ABSTRACT: Alpha-linolenic acid(ALA, C18:3delta9,12,15 ) is an essential fatty acid which has many sanitary functions to human. However, its contents in diets are often not enough. In plants, omega-3 fatty acid desaturases(FAD) catalyze linoleic acid(LA, C18:2delta9,12) into ALA. The seed oil of Glycine max contains high level of ALA. To investigate the functions of Glycine max omega-3FAD, the cDNA of GmFAD3 C was amplified by RT-PCR from immature seeds, then cloned into the shuttle expression vector p416 to generate the recombinant vector p4GFAD3C. The resulting vector was transformed into Saccharomyces cerevisiae K601 throuth LiAc method. The positive clones were screened on the CM(Ura-) medium and identified by PCR, and then cultured in CM (Ura-) liquid medium with exogenous LA in 20 degrees C for three days. The intracellular fatty acid composition of the engineering strain Kp416 and Kp4GFAD3C was analyzed by gas chromatography (GC). A novel peak in strain Kp4GFAD3C was detected,which was not detectable in control, Comparison of the retention times of the newly yielded peak with that of authentic standard indicated that the fatty acid is ALA. The content of ALA reached to 3.1% of the total fatty acid in recombinant strain, the content of LA correspondingly decreased from 22% to 16.2% by contrast. It was suggested that the protein encoded by GmFAD3 C can specifically catalyze 18 carbon PUFA substrate of LA into ALA by taking off hydrogen atoms at delta15 location. In this study, we expressed a Glycine max omega-3 fatty acid desaturase gene in S. cerevisiae; An efficient and economical yeast expressing system(K601-p416 system) which is suitable for the expression of FAD was built.
Sheng wu gong cheng xue bao = Chinese journal of biotechnology 02/2006; 22(1):33-8.
[Show abstract][Hide abstract] ABSTRACT: Acyl carrier protein (ACP), as an essential protein cofactor, plays an important role in de novo synthesis of fatty acids in plastids. In this study, the expression profile of peanut (Arachis hypogaea) AhACP1-1 and AhACP1-2 was analyzed in different tissues. The expression level of AhACP1-1 was highest in the seed, whereas expression was barely detected in the shoot, and AhACP1-2 was expressed in every tissue analyzed with the highest expression level detected in the leaf and seed. Overexpression (OE) and antisense-inhibition (AT) of AhACP1 in transgenic tobacco modified the transcript level of endogenous NtACPs, and the content of total lipids and composition of fatty acid in leaves were altered compared with the wild-type control. Transgenic OE-AhACP1 or AT-AhACP1 tobacco exhibited a significant increase or decrease in polyunsaturated C18:2 and C18:3 fatty acid content, and were more tolerant or sensitive to cold stress, respectively. It is suggested that AhACP1 bound with C18:1 might be the specific substrate of oleoyl-ACP thioesterase or glycerol-3-phosphate acyltransferase, and participates in membrane lipid synthesis.