Identification of genes differentially expressed in seeds of Polygonum aviculare in well established contrasting dormancy levels: an investigation assisted by predictive models

NATALIA LASPINA; MARINA SAMARIA; CRISTIAN MALAVERT; SILVINA FELITTI; DIEGO BATLLA; ROBERTO BENECH-ARNOLD

Changsha

Conferencia; The 11th Conference of the International Society for Seed Science (ISSS); 2014

International Society for Seed Science (ISSS)

Polygonum aviculare, an important weed of winter crops, naturally forms stable seed banks by cycling between dormant and non-dormant stages throughout seasons. Dormancy is defined as the inability of a seed to germinate under environmental conditions in which they might do. P.aviculare seeds are dormant at dispersion (D); low winter temperatures alleviate dormancy (ND) in a way well described by accurate population models; and high temperatures make seeds dormant again (SD). The objective of this work was to characterize the mechanisms involved in different dormancy levels of P. aviculare seeds. A transcriptome survey was carried out in order to isolate genes differentially expressed in dormant (D), non-dormant (ND) and seeds induced into secondary dormant (SD), generated with the assistance of predictive models. cDNA-AFLP experiments allowed the identification of 50 unigenes and 11 contigs differentially expressed with contrasting interesting profiles. Functional annotation was achieved for 28 of them. Most of the annotated sequences grouped in: 1) signal transduction mainly kinases; 2) hormone signaling; 3) transcriptional control; and 4) chromatin structure regulation. One of the genes differentially expressed in D, showed homology to a specific dormancy gene reported in Arabidopsis thaliana (DOG1), suggesting D and SD dormant states are directed by separate mechanisms. Two genes had hormone regulated domains, by GAs and auxines. Quantification of endogenous ABA during imbibition in seeds of different dormancy levels showed that sensitivity more than quantity of ABA should regulate the expression of dormancy in seeds entering SD, contrary to D treatment. Taken together, our results indicate that a number of genes differentially expressed in seeds with variable dormancy levels are mainly involved in regulation of transcription and hormone pathways. We also showed evidence that secondary dormancy induction and expression could be regulated mostly by changes in ABA sensitivity.