Frequencies and variation in cytosine methylation patterns in diploid and tetraploid cytotypes of Paspalum notatum

Abstract

Paspalum notatum Flügge is a grass species organized as an agamic complex. The objective of the current research was to survey the frequencies and variation of cytosine methylation at CCGG sequences in diploid and tetraploid genotypes, and to determine the occurrence of methylation changes associated with tetraploidization by using methylation-sensitive amplification polymorphism (MSAP) markers. No differences were found in the average proportions of methylated CCGG sites between cytotypes, but methylation patterns were significantly more variable in tetraploids. In both groups of plants, epigenetic and non-epigenetic variation correlated significantly when compared by Mantel tests. The evaluation of 159 common MSAP markers showed that 18.86 % of them differed in their methylation status in the different ploidies. Dendrogram analysis, reflecting epigenetic distances, showed that the four diploids and one experimentally-obtained sexually-reproducing tetraploid, grouped together. MSAP analysis performed on a diploid plant and its autotetraploid derivative showed that new epialleles emerged after tetraploidization. Sequencing of several MASP markers showed homologies with low copy genes, non-coding sequences and transposon/retrotransposon elements.

Morphological, Genome and Gene Expression Changes in Newly Induced Autopolyploid Chrysanthemum lavandulifolium (Fisch. ex Trautv.) Makino

“…The changes in genome after polyploidy formation have received wide attention in allopolyploids, where the changes to the nuclear environment, such as gene silencing and activation, the loss and gain of parental restriction sites were more profound compared to the autopolyploids [1,25]. However, the limited evidence currently available suggests that autopolyploids experience strong genome recombination in early stages, and these processes may become more essential in the long run [24]. Here, we used SRAP to identify 440 fragments.…”

“…Dar et al [23] reported that the DNA methylation level in tetraploid Phlox drummondii was higher than in the diploid. Rodriguez et al [24] indicated that diploid and tetraploid Paspalum notatum had no difference in the proportion of total methylation level but the methylation patterns were significantly more variable in tetraploids. Changes in DNA methylation are a common phenomenon in neopolyploids and has been associated with gene activation and silencing [25].…”

Sequence characterization, in silico mapping and cytosine methylation analysis of markers linked to apospory in Paspalum notatum

“…Methylation-sensitive RFLP experiments indicated that, in leaves, repetitive elements located at the apospory locus were methylated, but there was no difference in the methylation pattern of apomictic and sexual genotypes. However, Rodriguez et al (2012) reported variation in the methylation patterns of diploid (sexual) and tetraploid (sexual and apomicts) races of P. notatum based on MSAP (methylation-sensitive amplification polymorphism) markers. Moreover, the inactivation of a DNA methylation pathway in maize reproductive organs resulted in apomixis-like phenotypes ( Garcia-Aguilar et al , 2010 ).…”

Small RNA-seq reveals novel regulatory components for apomixis in Paspalum notatum

“…Moreover, increased sexuality was detected in diplosporous Eragrostis curvula plants subjected to environmental stress [28, 29]. Furthermore, among candidate mechanisms mediating apomixis, dosage effects or short-term epigenetic responses following polyploidization [30–32], and trans-effects generated by a non-recombinant, specific region in apomict genomes [17] have been proposed. In addition, genetic analyses in Arabidopsis thaliana and maize have shown that inactivation of members of the RNA-dependent DNA Methylation (RdDM) pathway results in reproductive phenotypes reminiscent of apomictic developments [33–36].…”