Abstract
Quality Protein Maize (QPM) is a hard kernel variant of the high-lysine mutant opaque2. Using γ-irradiation, we created opaque QPM variants to identify opaque2 modifier genes and to investigate deletion mutagenesis combined with Illumina sequencing as a maize (Zea mays) functional genomics tool. A K0326Y QPM deletion mutant was null for the 27- and 50-kD γ-zeins and abolished vitreous endosperm formation. Illumina exon and RNA sequencing revealed a 1.2-megabase pair deletion encompassing the 27- and 50-kD γ-zein genes on chromosome 7 and a deletion of at least 232 kb on chromosome 9. Protein body number was reduced by over 90%, while protein body size is similar to the wild type. Kernels hemizygous for the γ-zein deletion had intermediate 27- and 50-kD γ-zein levels and were semivitreous, indicating haploinsufficiency of these gene products in opaque2 endosperm modification. The γ-zein deletion further increased lysine in QPM in its homozygous and hemizygous states. This work identifies 27-kD γ-zein as an opaque2 modifier gene within the largest QPM quantitative trait locus and may suggest the 50-kD γ-zein also contributes to this quantitative trait locus. It further demonstrates that genome-wide deletions in nonreference maize lines can be identified through a combination of assembly of Illumina reads against the B73 genome and integration of RNA sequencing data.
Original language | English (US) |
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Pages (from-to) | 119-130 |
Number of pages | 12 |
Journal | Plant physiology |
Volume | 164 |
Issue number | 1 |
DOIs | |
State | Published - Jan 2014 |
Externally published | Yes |