Velvet bentgrass (Agrostis canina L.) is the likely ancestral diploid maternal parent of allotetraploid creeping bentgrass (Agrostis stolonifera L.)

Abstract

Understanding genetic relationships among the three most important Agrostis species will be important in breeding and genomic studies aimed at cultivar improvement. Creeping, colonial, and velvet bentgrasses (Agrostis stolonifera L., A. capillaris L., and A. canina L., respectively) are commercially important turfgrass species often used on golf courses. Velvet bentgrass is a diploid and creeping and colonial bentgrasses are both allotetraploids. A model for the genomic relationships among these species was previously developed from cytological evidence. The genome designations were A 1 A 1 for velvet bentgrass, A 1 A 1 A 2 A 2 for colonial bentgrass, and A 2 A 2 A 3 A 3 for creeping bentgrass. Here we used phylogenetic analysis based on DNA sequences of nuclear ITS and protein coding genes and the plastid trnK intron and matK gene to reexamine these relationships. In contrast to the previous model, the DNA sequence analysis suggested that velvet bentgrass was closely related to creeping bentgrass and it is likely the maternal parent of creeping bentgrass. Phylogenetic analysis of some conserved nuclear genes revealed a close relationship of the velvet bentgrass sequences with the A 2 subgenome sequences of creeping bentgrass. We therefore propose that velvet bentgrass be designated as having the A 2 genome, rather than the A 1 genome as in the previous model.

Molecular phylogenetics of cool-season grasses in the subtribes Agrostidinae, Anthoxanthinae, Aveninae, Brizinae, Calothecinae, Koeleriinae and Phalaridinae (Poaceae, Pooideae, Poeae, Poeae chloroplast group 1)

“…Nevertheless, many grass phylogenetic studies have been based on ITS, in whole or in part, including studies of Poeae (see Suppl. material 2 for the list of studies that generated new ITS sequences included in analyses here), of which only a few characterized infraspecific variation in ITS by cloning (Grebenstein et al 1998, Brysting et al 2004, Reichman et al 2006, Nikoloudakis et al 2008, Winterfeld et al 2009b, Rotter et al 2010, Zapiola and Mallory-Smith 2012, Wölk and Röser 2014, 2017). Although we did not conduct cloning studies to characterize incomplete concerted evolution in the grasses studied here, this is an obvious avenue for future research.…”

“…& Reut. (dryland bentgrass, 2 n =6 x =42, A 1 A 1 A 2 A 2 ) and A. gigantea (redtop bentgrass, 2 n =6 x =42, A 1 A 1 A 2 A 2 A 3 A 3 ) (Jones 1956a, c, b, Rotter et al 2007, 2010, Honig et al 2015). Characterizing relationships among these species has been challenging because most are allopolyploids.…”

“…Characterizing relationships among these species has been challenging because most are allopolyploids. A genus-wide phylogeny would be useful to turfgrass researchers because it would provide a broad evolutionary context for the genus, which is currently lacking, and may contribute to identifying the diploids that hybridized and formed the commercially important polyploid species of Agrostis (Rotter et al 2010). Aside from A. canina and A. transcaspica , none of the few known diploid species of Agrostis (e.g., A. alpina Scop., A. atlantica Maire & Trab., A. curtisii Kerguélen, A. delicatula Pourr.…”

Species Relationships in the Genus Agrostis Based on Flow Cytometry and MITE‐Display Molecular Markers

“…Polypogon species are morphologically similar to Agrostis species and are known to hybridize with them (Bark- Table). Reports suggest that A. vinealis is an autotetraploid whose genome consists of a doubling of A. canina (Jones, 1956;Rotter et al, 2010); these reports are consistent with this tetraploid clustering with the A. canina accessions.…”

“…V = 28; A|A, A^A^), but not to A. stolonifera (2n -4x-28; A^A^A-jA^). Recent genetic marker evidence suggests that A. canina may have contributed to the evolution oí A. stolonifera in contrast to what earlier studies suggest (Rotter et al, 2010). The cluster analysis shows that the primary cultivated species A. capillaris and A. stolonifera are more similar to each other than either is to A. canina (Fig.…”