A mutant deficient in S-adenosylhomocysteine hydrolase in Arabidopsis shows defects in root-hair developmentThis paper is one of a selection of papers published in a Special Issue from the National Research Council of Canada – Plant Biotechnology Institute.

Botany ◽  
2009 ◽  
Vol 87 (6) ◽  
pp. 571-584 ◽  
Author(s):  
Xianzhong Wu ◽  
Fengling Li ◽  
Allan Kolenovsky ◽  
Allan Caplan ◽  
Yuhai Cui ◽  
...  
Keyword(s):  
Root Hair ◽  
National Research Council ◽  
Plant Biotechnology ◽  
Adenosylhomocysteine Hydrolase ◽  
Root Hair Development ◽  
Dna Insertion ◽  
Visual Assay ◽  
Delayed Germination ◽  
Arabidopsis Mutant

Root-hair development is a process involving the interplay between genetic, hormonal, and environmental factors. An Arabidopsis mutant, referred to as sahh1, was initially recovered from a screen for delayed germination. Molecular characterization of the sahh1 mutant revealed that it contained a T-DNA insertion 82 bp 5′ to the coding sequence of S-adenosylhomocysteine hydrolase 1 (SAHH1, At4g13940), resulting in the reduction of SAHH1 expression. The resulting reduction in expression of SAHH1 produced plants with short, hairless roots, delayed germination, and slow growth. All of these phenotypes were restored to normal by complementing the sahh1 mutant with a full length cDNA. In plants, SAHH1 converts S-adenosylhomocysteine to homocysteine in the activated methyl cycle, and is a precursor for methionine and S-adenosylmethionine. Using the root hairless phenotype of the sahh1 mutant as a visual assay, the effects of SAHH1 deficiency on the synthesis of homocysteine, S-adenosylmethionine, 1-cyclopropane-1-carboxylic acid, and spermidine were investigated.

Molecular cloning and characterization of Dbr1, a 2-alkenal reductase from Artemisia annuaThe nucleotide sequence reported in this article has been deposited in the GenBank database under accession No. FJ750460.This paper is one of a selection of papers published in a Special Issue from the National Research Council of Canada – Plant Biotechnology Institute.

Botany ◽  
2009 ◽  
Vol 87 (6) ◽  
pp. 643-649 ◽  
Author(s):  
Yansheng Zhang ◽  
Keat H. Teoh ◽  
Darwin W. Reed ◽  
Patrick S. Covello
Keyword(s):  
Double Bond ◽  
Artemisia Annua ◽  
Sequence Similarity ◽  
National Research Council ◽  
Plant Biotechnology ◽  
In Planta ◽  
Carbon Double Bond ◽  
Expressed Sequence ◽  
Selection Of

The molecular genetics of carbon–carbon double bond reduction in the plant Artemisia annua  L. was studied. Expressed sequence tags from this plant were investigated for sequences with similarity to known double-bond reductases. This resulted in the isolation of a cDNA, corresponding to the gene A. annua Dbr1 (Double bond reductase1), encoding a member of the medium chain dehydrogenase/reductase protein superfamily with sequence similarity to tobacco allyl alcohol dehydrogenase. Recombinant A. annua Dbr1 protein was purified from Escherischia coli and shown to catalyze the reduction of the carbon–carbon double bond of 2-alkenals. This activity included the reduction of the double bond at C11–C13 in the artemisinin precursor artemisinic aldehyde, albeit with unnatural stereochemistry. The substrate specificity, product stereochemistry, and expression pattern of A. annua Dbr1 point to its involvement in planta in the detoxification of 2-alkenals, which may be generated under oxidative stress conditions.

The role of diacylglycerol acyltransferase-1 and phospholipid:diacylglycerol acyltransferase-1 and -2 in the incorporation of hydroxy fatty acids into triacylglycerol in Arabidopsis thaliana expressing a castor bean oleate 12-hydroxylase geneThis paper is one of a selection of papers published in a Special Issue from the National Research Council of Canada – Plant Biotechnology Institute.

Botany ◽  
2009 ◽  
Vol 87 (6) ◽  
pp. 552-560 ◽  
Author(s):  
Melanie Dauk ◽  
Patricia Lam ◽  
Mark A. Smith
Keyword(s):  
Fatty Acids ◽  
Neutral Lipids ◽  
National Research Council ◽  
Plant Biotechnology ◽  
Hydroxy Fatty Acids ◽  
Acyltransferase Activity ◽  
Unusual Fatty Acids ◽  
Arabidopsis Mutant ◽  
Mutant Lines

Expression of oleate 12-hydroxylase genes in Arabidopsis results in the accumulation of hydroxy fatty acids in seed triacylglycerol (TAG). The pathways by which these unusual fatty acids become incorporated into TAG are not well understood. We expressed a fatty acid hydroxylase cDNA in Arabidopsis mutant lines to assess the role of three enzymes implicated in TAG assembly in this species. Plants deficient in the expression of phospholipid:diacylglycerol acyltransferase-1 or -2 accumulated hydroxy fatty acids and showed no differences to equivalent transformed wild-type plants. Plants lacking diacylglylcerol acyltransferase activity were also able to accumulate hydroxy fatty acids in seed neutral lipids. Triacylglycerol species containing one and two hydroxy fatty acids were abundant, and small amounts of trihydroxy-TAG were detected. These results indicate that individually, the three enzymes do not play a major role in the incorporation of hydroxy fatty acids into TAG.

scholarly journals The Histone Chaperone NRP1 Interacts with WEREWOLF to Activate GLABRA2 in Arabidopsis Root Hair Development

2017 ◽  
Vol 29 (2) ◽  
pp. 260-276 ◽  
Author(s):  
Yan Zhu ◽  
Liang Rong ◽  
Qiang Luo ◽  
Baihui Wang ◽  
Nana Zhou ◽  
...  
Keyword(s):  
Root Hair ◽  
Histone Chaperone ◽  
Arabidopsis Root ◽  
Root Hair Development ◽  
Hair Development

scholarly journals A novel gene LbHLH from the halophyte Limonium bicolor enhances salt tolerance via reducing root hair development and enhancing osmotic resistance

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Xi Wang ◽  
Yingli Zhou ◽  
Yanyu Xu ◽  
Baoshan Wang ◽  
Fang Yuan
Keyword(s):  
Salt Tolerance ◽  
Root Hair ◽  
Salt Gland ◽  
Nacl Stress ◽  
35S Promoter ◽  
Osmotic Resistance ◽  
Salt Glands ◽  
Limonium Bicolor ◽  
Root Hair Development ◽  
Hair Development

Abstract Background Identifying genes involved in salt tolerance in the recretohalophyte Limonium bicolor could facilitate the breeding of crops with enhanced salt tolerance. Here we cloned the previously uncharacterized gene LbHLH and explored its role in salt tolerance. Results The 2,067-bp open reading frame of LbHLH encodes a 688-amino-acid protein with a typical helix-loop-helix (HLH) domain. In situ hybridization showed that LbHLH is expressed in salt glands of L. bicolor. LbHLH localizes to the nucleus, and LbHLH is highly expressed during salt gland development and in response to NaCl treatment. To further explore its function, we heterologously expressed LbHLH in Arabidopsis thaliana under the 35S promoter. The overexpression lines showed significantly increased trichome number and reduced root hair number. LbHLH might interact with GLABRA1 to influence trichome and root hair development, as revealed by yeast two-hybrid analysis. The transgenic lines showed higher germination percentages and longer roots than the wild type under NaCl treatment. Analysis of seedlings grown on medium containing sorbitol with the same osmotic pressure as 100 mM NaCl demonstrated that overexpressing LbHLH enhanced osmotic resistance. Conclusion These results indicate that LbHLH enhances salt tolerance by reducing root hair development and enhancing osmotic resistance under NaCl stress.

scholarly journals Responses of root hair development to elevated CO2

2011 ◽  
Vol 6 (9) ◽  
pp. 1414-1417 ◽  
Author(s):  
Yao Fang Niu ◽  
Gu Lei Jin ◽  
Ru Shan Chai ◽  
Huan Wang ◽  
Yong Song Zhang
Keyword(s):  
Elevated Co2 ◽  
Root Hair ◽  
Root Hair Development ◽  
Hair Development

Experimental and Analytical Characterization of Alternative Aviation Fuel Sprays Under Realistic Operating Conditions

2018 ◽  
Author(s):  
Andrew Corber ◽  
Nader Rizk ◽  
Wajid Ali Chishty
Keyword(s):  
Experimental Data ◽  
Alternative Fuels ◽  
Laser Sheet ◽  
National Research Council ◽  
Diagnostic System ◽  
Operating Conditions ◽  
Aviation Fuel ◽  
Injection System ◽  
Test Time

The National Jet Fuel Combustion Program (NJFCP) is an initiative, currently being led by the Office of Environment & Energy at the FAA, to streamline the ASTM jet fuels certification process for alternative aviation fuels. In order to accomplish this objective, the program has identified specific applied research tasks in several areas. The National Research Council of Canada (NRC) is contributing to the NJFCP in the areas of sprays and atomization and high altitude engine performance. This paper describes work pertaining to atomization tests using a reference injection system. The work involves characterization of the injection nozzle, comparison of sprays and atomization quality of various conventional and alternative fuels, as well as use of the experimental data to validate spray correlations. The paper also briefly explores the application viability of a new spray diagnostic system that has potential to reduce test time in characterizing sprays. Measurements were made from ambient up to 10 bar pressures in NRC’s High Pressure Spray Facility using optical diagnostics including laser diffraction, phase Doppler anemometry (PDA), LIF/Mie Imaging and laser sheet imaging to assess differences in the atomization characteristics of the test fuels. A total of nine test fluids including six NJFCP fuels and three calibration fluids were used. The experimental data was then used to validate semi-empirical models, developed through years of experience by engine OEMs and modified under NJFCP, for predicting droplet size and distribution. The work offers effective tools for developing advanced fuel injectors, and generating data that can be used to significantly enhance multi-dimensional combustor simulation capabilities.

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