Identical substitutions in magnesium chelatase paralogs result in chlorophyll-deficient soybean mutants.
Bottom Line: This mutation was identified in the ChlI1b gene, a paralog of ChlI1a.Protein sequence alignments of the two Mg-chelatase subunits indicated that the sites of amino acid modification in MinnGold, T219H, and CD-5 are highly conserved among photosynthetic species.These results suggest that amino acid alterations in this critical domain may create competitive inhibitory interactions between the mutant and wild-type ChlI1a and ChlI1b proteins.
Affiliation: Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, Minnesota 55108.Show MeSH
Mentions: The spontaneous, nonlethal yellow foliage mutant (Figure 1) was first observed in a segregating F3 population derived from a cross between M99-274166 × ‘MN0091’. The F3 population was advanced by modified single seed descent and exhibited a segregation ratio of 157 green (wild-type) plants to 50 yellow (mutant) individuals. The ratio of 157:50 for the wild-type:chlorophyll-deficient phenotype is consistent with a single-locus, recessive mutation (χ2 test, P = 0.78). The mutant phenotype appears more vigorous than previously identified chlorophyll-deficient soybean mutants. Measurement of leaf chlorophyll levels from tissue collected from the second true leaves at the V5 leaf stage show that this mutant displayed a dramatic reduction of both chlorophyll a and chlorophyll b relative to wild-type soybean plants (Figure 1). This mutant was given the name MinnGold because of its bright yellow leaf coloration during early foliar development.
Affiliation: Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, Minnesota 55108.