Inheritance of superoxide dismutase (Sod-1) in a perennial × annual ryegrass cross and its allelic distribution among cultivars

Abstract

Identifying annual ryegrass contamination in perennial ryegrass seed lots has been of major interest in seed-testing laboratories and for seed regulatory agencies in the USA for many years. This study was conducted to characterize a superoxide dismutase locus ( Sod-1) and determine its potential to distinguish cultivated ryegrass species. The inheritance of Sod-1 was evaluated in a three-generation annual x perennial ryegrass mapping population and segregation fitted an expected 1:2:1 ratio for a single locus with two alleles. The molecular form of the Sod-1 locus was determined by H(2)O(2) and KCN inhibitor assays which indicated that the Sod-1, and a second independently segregating Sod-2, locus were both Cu/ZnSod enzymes. The common alleles at the Sod-1 locus were scored in 13 annual and 24 perennial ryegrass cultivars to determine the potential of using this locus for species separation. The Sod-1b allele was homozygous in 98% of perennial ryegrass individuals from 24 cultivars, but those not 100% homozygous for Sod-1b were seed lots with unknown contamination from annual ryegrass. These results indicate that the Sod-1b allele in the homozygous condition is a good indicator of perenniality. All eight annual ryegrass cultivars originating in Europe or Asia had a low frequency of Sod-1b homozygous individuals or none at all. The five cultivars originating in the Western Hemisphere, however, had genotype frequencies for homozygous Sod-1b of up to 56%. The potential of the Sod-1 locus to serve as a test to separate the two growth forms depends on the source of the annual-type contamination.

Genetic linkage mapping of an annual × perennial ryegrass population

“…The Pgi-2 locus is well studied in ryegrass and was mapped to linkage group 1 . Warnke et al (2002) reported on the segregation of the Sod-1 locus, and the present paper is the first to assign this locus to a defined linkage group.…”

“…Inaccuracy of the SRF test (Floyd and Barker 2002) has led to a search for an alternative or supplemental test to more accurately detect annual ryegrass contamination of perennial ryegrass (Warnke et al 2002). Two leaf isozymes have been identified that can be used as species indicators.…”

Studies on quantitative trait loci related to superoxide dismutase in mirror carp (Cyprinus carpioL.)

“…Studies on other species have demonstrated that QTL is a proven technique; QTL for SOD trait has also been conducted on plants. Warnke, Barker, Brilman, Young and Cook () located two QTLs of SOD‐1 a,b genes in a perennial×annual ryegrass cross. SOD and small heat‐shock protein traits associated QTL have been located in Ls11 of Drosophila melanogaster (Vieira, Pasyukova, Zeng, Hackett, Lyman & Mackay ).…”

Improving the Yield and Nutritional Quality of Forage Crops

“…Those identified are studied in relation to biomass and growth traits; in M. sativa QTL has been used for lodging resistance and vigor ( McCord et al, 2014 ), plant height and regrowth following harvests in association with MsaciB ( Robins et al, 2007 ), candidate gene analysis for flowering and stem height through CONSTANS-LIKE ( Herrmann et al, 2010 ) and biochemical markers of ROS resistance genes for drought tolerance correlated to DM ( Maghsoodi et al, 2017 ). The expression of other ROS associated genes of the Iron-Superoxide Dismutase family ( Myouga et al, 2008 ) have also been linked to increases in DM in both the legume M. sativa ( McKersie et al, 2000 ) and grass Lolium cultivars ( Warnke et al, 2002 ).…”