INVESTIGADORES
PESSINO Silvina Claudia
artículos
Título:
An apomixis-linked ORC3-like pseudogene is associated with silencing of its functional homolog in apomictic Paspalum simplex
Autor/es:
SIENA L; ORTIZ JPA; CALDERINI O; PAOLOCCI F; CÁCERES ME; KAUSHAL P; GRISAN S; PESSINO SC; PUPILLI F
Revista:
JOURNAL OF EXPERIMENTAL BOTANY
Editorial:
OXFORD UNIV PRESS
Referencias:
Lugar: Oxford; Año: 2016
ISSN:
0022-0957
Resumen:
Apomixis in plants consists of asexual reproduction by seeds. Here we characterized at structural and functional levelsan apomixis-linked sequence of Paspalum simplex homologous to subunit 3 of the ORIGIN RECOGNITION COMPLEX(ORC3). ORC is a multiprotein complex which controls DNA replication and cell differentiation in eukaryotes. ThreePsORC3 copies were identified, each one characterized by a specific expression profile. Of these, PsORC3a, specificfor apomictic genotypes, is a pseudogene that was poorly and constitutively expressed in all developmental stages ofapomictic flowers, whereas PsORC3b, the putative functional gene in sexual flowers, showed a precise time-relatedregulation. Sense transcripts of PsORC3 were expressed in the female cell lineage of both apomictic and sexual reproductivephenotypes, and in aposporous initials. Although strong expression was detected in sexual early endosperm,no expression was present in the apomictic endosperm. Antisense PsORC3 transcripts were revealed exclusively inapomictic germ cell lineages. Defective orc3 mutants of rice and Arabidopsis showed normal female gametophytesalthough the embryo and endosperm were arrested at early phases of development. We hypothesize that PsORC3ais associated with the down-regulation of its functional homolog and with the development of apomictic endospermwhich deviates from the canonical 2(maternal):1(paternal) genome ratio.