INVESTIGADORES
PESSINO Silvina Claudia
congresos y reuniones científicas
Título:
An apomixis-linked ORIGIN OF RECOGNITION COMPLEX 3 gene is expressed as a long non coding RNA that down regulates its functional homologous counterpart in apomictic Paspalum simplex
Autor/es:
SIENA L; ORTIZ JPA; CALDERINI O; PAOLOCCI F; CÁCERES ME; KAUSHAL P; GRISAN S; PESSINO SC; PUPILLI F
Lugar:
Foz de Iguazú
Reunión:
Congreso; 11th International Congress Plant Molecular Biology 2015 (IPMB 2015); 2015
Institución organizadora:
International Plant Molecular Biology
Resumen:
Apomixis, is controlled in Paspalum by a single and recombinationally repressed locus. An apomixis-linked sequence of P. simplex shows homology to the subunit N. 3 of the ORIGIN OF RECOGNITION COMPLEX, a protein aggregate that controls DNA replication and cell differentiation in eukaryotes. PsORC3 exists in three copies in P. simplex: PsORC3a is specific of apomictic genotypes and is unable to be translated into a functional protein, PsORCb is common to apomictic and sexual genotypes, likely coding a functional protein and PsORC3c, that segregates independently from apomixis. Gene-specific real time PCR showed that the expression of PsORC3b in sexual flowers was low before anthesis and then raised until the first phases of seed development. Conversely, both PsORC3a and PsORC3c were poorly and constitutively expressed in all stages of apomictic ovule development. In situ hybridisation showed that ORC3 sense transcripts0107were expressed in the nucellus, megaspore mother cell, functional megaspore, polar nuclei and egg cells of both apomictic and sexual ovules and in aposporous initials of the apomictic ones. Although strong expression was detected in sexual early endosperm, no expression was present in apomictic one. Antisense PsOCR3 transcripts were revealed exclusively in apomictic germ cell lineages. Defective orc3 mutants of rice and Arabidopsis showed arrested embryo/endosperm development whereas the female gametophyte was normal. We hypothesize that PsORC3a might be involved in the development of endosperm deviating from the 2 (maternal) : 1 (paternal) genome ratio in apomictic ovules by silencing the functional allele PsORC3b via an antisense-mediated mechanism.