Disease relevance of CSR1

• Four mutants (A122V, W574S, W574L and S653N) of the AHAS gene from Arabidopsis thaliana were constructed, expressed in Escherichia coli, and the enzymes were purified [1].

High impact information on CSR1

• The Trp pathway enzymes and cytosolic glutamine synthetase were induced under all of the amino acid starvation test conditions, whereas methionine synthase and acetolactate synthase were not [2].
• This report describes the 3D structure of Arabidopsis thaliana AHAS in complex with five sulfonylureas (to 2.5 A resolution) and with the imidazolinone, imazaquin (IQ; 2.8 A) [3].
• The ALS gene encoding acetolactase synthase, which confers resistance to chlorsulfuron, functioned as a versatile marker for selection of plants grown in tissue culture as well as in soil [4].
• Nucleotide sequence of a mutant acetolactate synthase gene from an imidazolinone-resistant Arabidopsis thaliana var. Columbia [5].
• Taking advantage of the properties of such migration-selection balance, an artificial cline was built up to optimize the conditions where the fitness cost of two herbicide-resistant mutants (acetolactate synthase and auxin-induced target genes) in the model species Arabidopsis thaliana could be more accurately measured [6].

Biological context of CSR1

• DNA and deduced amino acid sequences were determined for the A5 and A19 genes, and an AHAS cDNA clone isolated from a leaf library [7].
• A double mutant allele, csr1-4, of Arabidopsis thaliana encodes an acetolactate synthase with altered kinetics [8].
• Our experimental design allows us to conclude that this fitness cost of resistance is caused by the pleiotropic effect of the introduced acetolactate synthase gene rather than other potential costs associated with the plasmid or mutational changes induced by plant transformation [9].
• The complexity of the AHAS multigene family in the allotetraploid species B. napus is much greater than reported for Arabidopsis thaliana and Nicotiana tabacum [10].
• They probably encode the AHAS enzymes essential for plant growth and development [10].

Associations of CSR1 with chemical compounds

• The dominant csr1-1 allele encodes an ALS resistant to chlorsulfuron and triazolopyrimidine sulfonamide while the dominant csr1-2 allele encodes an ALS resistant to imazapyr and pyrimidyl-oxy-benzoate [11].
• A122V showed reduced affinity for all three cofactors, whereas S653N bound FAD more strongly than wild-type AHAS [1].
• The enzyme is part of a superfamily of ThDP-dependent 2-oxo acid decarboxylases that includes pyruvate decarboxylase, benzoylformate decarboxylase, and acetohydroxy acid synthase, among others [12].
• The regulatory subunit of Arabidopsis thaliana AHAS possesses a sequence repeat and we have suggested previously that one repeat binds leucine while the second binds valine or isoleucine, with synergy between the two sites [13].
• Feedback inhibition by L-valine (L-Val), L-leucine (L-Leu) and L-isoleucine (L-Ile) of acetolactate synthase extracted from wild type and mutants fitted a mixed competitive pattern most closely [8].

Other interactions of CSR1

• By analyzing morphological characters and simple fitness components, the cost associated with each of eight herbicide resistance alleles (acetolactate synthase, cellulose synthase, and auxin-induced target genes) was studied in the model plant Arabidopsis thaliana [14].

Analytical, diagnostic and therapeutic context of CSR1

• The molecular breeding tools described herein create the basis for rapidly identifying new mutations in AHAS and performing MAS for herbicide resistance genes in sunflower [15].
• Molecular characterization of true and ectopic gene targeting events at the acetolactate synthase gene in Arabidopsis [16].
• Here, the crystallization and preliminary X-ray diffraction analysis of the catalytic subunit of Arabidopsis thaliana AHAS in complex with the sulfonylurea herbicide chlorimuron ethyl are reported [17].

References