Survey of repetitive sequences in Eragrostis curvula cDNA EST libraries obtained from genotypes with different ploidy level

ROMERO J; SELVA JP; PESSINO S; VIVIANA ECHENIQUE; GARBUS I

BIOLOGIA PLANTARUM

SPRINGER

Lugar: Berlin; Año: 2016 vol. 60 p. 55 - 67

0006-3134

Eragrostis curvula (Schrad) Nees (weeping lovegrass) represents an important cultivated forage resource in semiarid regions, and the most useful cultivars are tetraploid and reproduce by pseudogamous diplosporous apomixis. We previously produced a series of genetically related E. curvula lines that provide a suitable system for the identification of gene(s) involved in diplosporous apomixis and ploidy, including a natural apomictic tetraploid (T), a diploid sexual line (D) and a tetraploid sexual plant (C). A collection of ESTs was generated from cDNA libraries obtained from panicles of D, T and C, and leaves of T. The present study aimed to analyze the repetitive content of these four cDNA libraries and further identify and characterize transposable element (TE)-related ESTs. Repetitive sequences were identified though the interface RepeatMasker (RM) using the database Repbase Update and the further classification of transposable elements was performed manually from the RM output. The differential contribution of ESTs with identity to TEs among libraries was further evaluated and such differences were validated through qRT-PCR. We found that the percentage of repetitive content in the leaf cDNA library was almost double that in inflorescence libraries, with retrotransposons contributing most in all libraries. The expression of TE-related ESTs was compared in cDNA samples extracted from D, T and C leaves or inflorescences, revealing that seven mRNAs containing MuDR-like DNA transposons, Gypsy-like and Copia-like retrotransposons were differentially represented according to tissue, reproductive mode or ploidy. The euploid series of the Eragrostis curvula is a useful model to the study the epigenomic changes produced after changes in ploidy. The present work constitutes the first detailed report on repetitive sequences of Eragrostis curvula at the transcriptome level.