DNA Polymorphisms at Bermudagrass Microsatellite Loci and Their Use in Genotype Fingerprinting

Abstract

The turf-type bermudagrasses include diploid Cynodon transvaalensis Burtt Davy, tetraploid C. dactylon (L.) Pers., and sterile triploid hybrids produced by crosses of these species. The objective of thiis study was to develop a set of mierosatellite markers that could distinguish among commercially important turf-type cultivars. A genomic library enriched for tfie [CA/GT]^ repeat motif was constructed from DNA of the Tifway' fiybrid and sequenced to identify mierosatellite regions. Twenty-five microsatellite-flanking primer sets were developed and used to genotype two plant introductions and 12 turf-type cultivars. These primer sets produced an average of 10 amplicons across tfie 14 DNA templates. Sequences of selected amplicons revealed polymorphism resulting from expansion and/or contraction of the microsatellite and from indel mutations in the microsatellite flanking regions. As few as two primer sets were sufficient to differentiate all unrelated introduction lines and cultivars. Tfie primer sets failed to distinguish among closely related cultivars developed by selection of natural variants, but one primer set uniquely distinguished the cultivar TifEagle from its irradiated parent cultivar. Tfiese genomic microsatellites were not derived from gene coding sequences and will supplement tfie existing expressed sequence tag (EST)-based bermudagrass microsatellites. Tfiey will be most useful for evaluating tfie genetic diversity of Cynodon accessions and distinguishing among cultivars that exploit thils diversity.

The genetic and phenotypic variability of interspecific hybrid bermudagrasses (Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy) used on golf course putting greens

“…Harris-Shultz et al (2011) reported that the polymorphic fragment amplified by the Chase 109 primer was approximately 142 base pairs larger than the fragment length reported by Kamps et al (2011). Kamps et al (2011) suggested that microsatellite instability in plant tissues may be affected by irradiation, similar to mammalian tumors (Haines et al 2010), potentially explaining why TifEagle is distinguishable from Tifgreen-derived cultivars using the Chase 109 primer. This hypothesis is logical considering that TifEagle has been reported to be a mutant derived from an irradiated Tifway II rhizome (Hanna and Elsner 1999).…”

“…2). Kamps et al (2011) also failed to differentiate Tifgreen, Tifdwarf, Champion Dwarf, Floradwarf, or MS-Supreme using SSR markers.

Fig. 2Dendrograms display the genetic relationships among hybrid bermudagrasses ( Cynodon dactylon (L.) Pers.

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“…These dendrograms demonstrate that ‘Tifgreen’ and all Tifgreen-derived cultivars cannot be genetically distinguished from one another. a Figure reproduced with permission from Crop Science and Kamps et al (2011). b Figure reproduced with permission from Crop Science and Capo-chichi et al (2005).…”

“…While some previously described SSR markers were not able to identify TifEagle from its relatives, a single amplicon from a primer (Chase 109) has been used to identify TifEagle from Tifgreen- and Tifgreen-derived cultivars (Harris-Shultz et al 2011; Kamps et al 2011). Harris-Shultz et al (2011) reported that the polymorphic fragment amplified by the Chase 109 primer was approximately 142 base pairs larger than the fragment length reported by Kamps et al (2011).…”

“…Figure 2 shows five dendrograms generated from genetic diversity research conducted by Capo-chichi et al (2005), Harris-Shultz et al (2010), Kamps et al (2011), Wang et al (2010), and Zhang et al (1999). These dendrograms demonstrate that not all Tifgreen and Tifgreen-derived cultivars can be genetically distinguished from one another, despite variable success SSR markers reported by Harris-Shultz et al (2011) and Kamps et al (2011). The ability to identify unique ultradwarf bermudagrass cultivars would facilitate the production of genetically pure planting material, although this purity verification must be performed frequently, because the same pedigree stock production process that led to off-types will be used again.…”