γ-Aminobutyrate transaminase limits the catabolism of γ-aminobutyrate in cold-stressed Arabidopsis plants: insights from an overexpression mutant

Botany ◽  
2010 ◽  
Vol 88 (5) ◽  
pp. 522-527 ◽  
Author(s):  
Jeffrey P. Simpson ◽  
Shawn M. Clark ◽  
Andrea Portt ◽  
Wendy L. Allan ◽  
Amina Makhmoudova ◽  
...  

We tested the hypothesis that γ-aminobutyrate transaminase (GABA-T) regulates the supply of succinate semialdehyde for succinate semialdehyde dehydrogenase or NADPH-dependent glyoxylate/succinate semialdehyde reductase 1 (GLYR1) during stress. Constitutive overexpression (OX) lines of GABA-T were generated in Arabidopsis via the floral-dip method for Agrobacterium-mediated transformation. Polymerase chain reaction enabled selection of four transgenic lines with higher GABA-T transcript levels than the wild-type (WT), but assay of cell-free leaf extracts revealed that only OX1 had elevated GABA-T activity. Brief cold treatments (4 °C exposure for 20 min or 1 h in the dark) increased leaf GABA concentrations in both the WT and OX1, but the concentrations in OX1 were consistently lower. These findings confirm that GABA-T limits the catabolism of GABA when its production is stimulated by stress, and suggest a bioengineering strategy for improving the availability of succinate semialdehyde for the Krebs cycle or GLYR1, a potential redox-modulating reaction during stress.

Plant Disease ◽  
1999 ◽  
Vol 83 (5) ◽  
pp. 482-485 ◽  
Author(s):  
Margaret J. Green ◽  
Dan A. Thompson ◽  
Donald J. MacKenzie

A simple and efficient procedure for the extraction of high-quality DNA from phytoplasma-infected woody and herbaceous plants for polymerase chain reaction (PCR) detection is described. This procedure does not require phenol, chloroform, or alcohol for the precipitation of nucleic acids. Herbaceous and woody plant material are extracted in an identical manner with no additional purification or enrichment steps required. The method utilizes commercially available microspin-column matrices, and the extraction of total DNA can be achieved in less than 1 h. The method has been used to successfully purify phytoplasma DNA from whole leaves, leaf petioles and midribs, roots, and dormant wood from a diverse selection of plant material. The phytoplasmas detected by PCR include pear decline, western X-disease, peach yellow leaf roll, peach rosette, apple proliferation, Australian grapevine yellows, and Vaccinium witches'-broom.


2021 ◽  
pp. 3224-3228
Author(s):  
Budi Utomo ◽  
Rimayanti Rimayanti ◽  
Indah Norma Triana ◽  
Amaq Fadholly

Background and Aim: The genetic improvement of cattle through livestock section is based on quantitative, qualitative, and molecular characteristics. This study examined polymorphisms of the melanocortin-4 receptor (MC4R) and leptin genes as a reference for the selection of superior breeds in Madrasin cattle. Materials and Methods: The leptin and MC4R genes of Madrasin cattle were amplified using polymerase chain reaction (PCR); then, restriction fragment length polymorphism of the leptin gene was performed using the restriction enzyme BsaA1, at site 2793 with ACGT point position. Results: The leptin gene was divided into three bands, namely, AA with one fragment (522 bp), CG with two fragments (441 bp and 81 bp), and AG with three fragments (522 bp, 441 bp, and 81 bp). The MCR-4 gene was divided into three bands, namely, 493 bp, 318 bp, and 175 bp. Conclusion: The MC4R and leptin genes can act as molecular markers for growth traits in Madrasin cattle and can be used to genetically optimize and improve growth. The GG allele of the MC4R gene and the AA allele of the leptin gene can be used in Madrasin cattle.


1990 ◽  
Vol 10 (10) ◽  
pp. 5235-5243 ◽  
Author(s):  
D M Baronas-Lowell ◽  
J R Warner

In the yeast Saccharomyces cerevisiae, L30 is one of many ribosomal proteins that is encoded by two functional genes. We have cloned and sequenced RPL30B, which shows strong homology to RPL30A. Use of mRNA as a template for a polymerase chain reaction demonstrated that RPL30B contains an intron in its 5' untranslated region. This intron has an unusual 5' splice site, C/GUAUGU. The genomic copies of RPL30A and RPL30B were disrupted by homologous recombination. Growth rates, primer extension, and two-dimensional ribosomal protein analyses of these disruption mutants suggested that RPL30A is responsible for the majority of L30 production. Surprisingly, meiosis of a diploid strain carrying one disrupted RPL30A and one disrupted RPL30B yielded four viable spores. Ribosomes from haploid cells carrying both disrupted genes had no detectable L30, yet such cells grew with a doubling time only 30% longer than that of wild-type cells. Furthermore, depletion of L30 did not alter the ratio of 60S to 40S ribosomal subunits, suggesting that there is no serious effect on the assembly of 60S subunits. Polysome profiles, however, suggest that the absence of L30 leads to the formation of stalled translation initiation complexes.


2006 ◽  
Vol 52 (11) ◽  
pp. 1027-1035 ◽  
Author(s):  
Hyesuk Kong ◽  
Cheryl D Patterson ◽  
Robin E Mitchell ◽  
Jeffrey S Buyer ◽  
M Catherine Aime ◽  
...  

A mutant of Pseudomonas syringae pv. tagetis EB037 with limited ability to produce tagetitoxin was isolated after transposon mutagenesis and the mutation was characterized. The mutation occurred in a gene with a high degree of sequence identity to exbD. exbD is contiguous with tonB and exbB upstream and with a gene for a TonB-dependent receptor downstream. Using reverse transcription – polymerase chain reaction with RNA from the wild-type and exbD mutant strains, we demonstrated that the mutation in exbD did not have a polar affect on the expression of downstream genes. The exbD mutant was able to grow well in conditions where iron is not freely available. Siderophore production by the exbD mutant was similar to that of the wild-type strain. We conclude that the mutation in exbD disrupts tagetitoxin production without compromising iron metabolism. The results indicate that tagetitoxin export by P. syringae pv. tagetis involves an efflux pump that requires a functional TonB system that is not essential for normal iron metabolism.Key words: Pseudomonas syringae pv. tagetis, Pseudomonas putida, tagetitoxin, exbD, exbB, tonB, TonB system, Helianthus annuus L.


1990 ◽  
Vol 10 (10) ◽  
pp. 5235-5243
Author(s):  
D M Baronas-Lowell ◽  
J R Warner

In the yeast Saccharomyces cerevisiae, L30 is one of many ribosomal proteins that is encoded by two functional genes. We have cloned and sequenced RPL30B, which shows strong homology to RPL30A. Use of mRNA as a template for a polymerase chain reaction demonstrated that RPL30B contains an intron in its 5' untranslated region. This intron has an unusual 5' splice site, C/GUAUGU. The genomic copies of RPL30A and RPL30B were disrupted by homologous recombination. Growth rates, primer extension, and two-dimensional ribosomal protein analyses of these disruption mutants suggested that RPL30A is responsible for the majority of L30 production. Surprisingly, meiosis of a diploid strain carrying one disrupted RPL30A and one disrupted RPL30B yielded four viable spores. Ribosomes from haploid cells carrying both disrupted genes had no detectable L30, yet such cells grew with a doubling time only 30% longer than that of wild-type cells. Furthermore, depletion of L30 did not alter the ratio of 60S to 40S ribosomal subunits, suggesting that there is no serious effect on the assembly of 60S subunits. Polysome profiles, however, suggest that the absence of L30 leads to the formation of stalled translation initiation complexes.


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