Genetic Loci Governing Androgenic Capacity in Perennial Ryegrass (Lolium perenne L.)

Abstract

Immature pollen can be induced to switch developmental pathways from gametogenesis to embryogenesis and subsequently regenerate into homozygous, diploid plants. Such androgenic production of doubled haploids is particularly useful for species where inbreeding is hampered by effective self-incompatibility systems. Therefore, increasing the generally low androgenic capacity of perennial ryegrass (Lolium perenne L.) germplasm would enable the efficient production of homozygous plant material, so that a more effective exploitation of heterosis through hybrid breeding schemes can be realized. Here, we present the results of a genome-wide association study in a heterozygous, multiparental population of perennial ryegrass (n = 391) segregating for androgenic capacity. Genotyping-by-sequencing was used to interrogate gene- dense genomic regions and revealed over 1,100 polymorphic sites. Between one and 10 quantitative trait loci (QTL) were identified for anther response, embryo and total plant production, green and albino plant production and regeneration. Most traits were under polygenic control, although a major QTL on linkage group 5 was associated with green plant regeneration. Distinct genetic factors seem to affect green and albino plant recovery. Two intriguing candidate genes, encoding chromatin binding domains of the developmental phase transition regulator, Polycomb Repressive Complex 2, were identified. Our results shed the first light on the molecular mechanisms behind perennial ryegrass microspore embryogenesis and enable marker-assisted introgression of androgenic capacity into recalcitrant germplasm of this forage crop of global significance.

Comparative Analysis of In Vitro Responses and Regeneration between Diverse Bioenergy Sorghum Genotypes

“…Furthermore, as regenerability is associated with organ formation, a better understanding of the genetics of in vitro responsiveness and regeneration could improve our understanding of the genetic loci/genes associated with the improved resource allocation required for new or replacement organ development, which would be of relevance to yield and performance enhancement [33]. Several studies have used QTL analysis and GWAS to identify genetic loci and candidate genes involved in tissue culture responsiveness and regeneration in a limited number of plant types [34][35][36], but an understanding of the overall genes and pathways associated with this process remains to be resolved, especially for recalcitrant sorghum.…”

The complex genetic architecture of recombination and structural variation in wheat uncovered using a large 8-founder MAGIC population

“…MAGIC populations have been developed as genetic resource panels in a number of species [Cavanagh et al, 2008, but have seen the greatest uptake in wheat in terms of both number of different populations and size thereof. The first plant MAGIC population was developed in Arabidopsis thaliana [Kover et al, 2009], and since then populations have been developed in crops including barley [Mathew et al, 2018], chickpea [Gaur et al, 2012], rice [Bandillo et al, 2013], ryegrass [Begheyn et al, 2018] and tomato [Pascual et al, 2015]. None of these populations in other crops explore the full range of potential intercrosses possible in the early stages of MAGIC designs, and besides [Bandillo et al, 2013] none of them have been genotyped on more than 1000 lines.…”

Comparative Analysis of In Vitro Responses and Regeneration Between Diverse Bioenergy Sorghum Genotypes

“…Several studies have targeted the genetic control of in vitro responsiveness in a variety of plants. Many have involved QTL identification (Bolibok and Rakoczy-Trojanowska 2006, Song et al 2010, Tyagi et al 2010, Trujillo-Moya et al 2011, Yang et al 2011, Krzewska et al 2012, Li et al 2013), and more recently, GWAS (Begheyn et al 2018, Ma et al 2018, Zhang et al 2018). These studies have identified several genetic loci and candidate genes associated with various aspects of in vitro responsiveness.…”

“…Furthermore, as regenerability is associated with organ formation, a better understanding of the genetics of in vitro responsiveness and regeneration could improve our understanding of the genetic loci/genes associated with the improved resource allocation required for new or replacement organ development, which would be of relevance to yield and performance enhancement (Arikita et al 2013). Several studies have used QTL analysis and GWAS to identify genetic loci and candidate genes involved in tissue culture responsiveness and regeneration in a limited number of plant types (Tyagi et al 2010, Begheyn et al 2018, Ma et al 2018), but an understanding of the overall genes and pathways associated with this process remains to be resolved, especially for recalcitrant sorghum.…”