Genomic screening in dioecious ‘‘yerba mate’’ tree (Ilex paraguariensis A. St. Hill., Aquifoliaceae) through representational difference analysis

ALEXANDRA M. GOTTLIEB, LIDIA POGGIO

GENETICA

SPRINGER

Lugar: New York; Año: 2010 vol. 138 p. 567 - 578

0016-6707

The ‘‘yerba mate’’ tree, Ilex paraguariensis, is afunctionally dioecious crop species with economic relevancein several South American countries. We report agenomic screening accomplished through representationaldifference analysis (RDA) in male and female I. paraguariensistrees. The aim of the present paper was to investigatethe occurrence of sex-related genomic differences inorder to develop an early gender detection molecularmethod that could help reducing energy inputs during the‘‘yerba mate’’ processing and that could be suitable forbreeding programs. An intra-experiment redundancy wasdetected via SSCP analysis and sequence characterization.Taking together both reciprocal RDA assays, fragmentsisolated can be discriminated into three main categories. Thefirst category of fragments shows spurious affinities withavailable deposited sequences and could be considered asspecific to I. paraguariensis. The second category comprisessequences identified as organellar or ribosomal plant DNA.Sequences grouped in the third category involve clones akinto conserved domains of retrotransposons (RNaseH, integrasesand/or chromodomains) from at least two distinctlineages of Ty3/Gypsy retrotransposons and one from Ty1/Copia retroelements, which in addition are associated to sexdetermination regions of the Solanaceae, Caricaceae andSalicaceae. A contig sequence was assembled that codes foran integrase core domain and a chromodomain. The phylogeneticanalysis of the so-called IPRE (for I. paraguariensisretroelement) integrase domain indicates that itbelongs to the Del lineage of the Chromoviridae. This is thefirst report of mobile elements isolated and detected fromthe ‘‘yerba mate’’ tree. Although RDA derived fragments, sofar tested, have been retrieved from both sexes with similarsequences, association to sex related regions cannot becompletely discarded. Implications of present results arefurther discussed.