Apomixis Frequency under Stress Conditions in Weeping Lovegrass (Eragrostis curvula)

RODRIGO JUAN MANUEL; ZAPPACOSTA DIEGO; SELVA JUAN PABLO; GARBUS INGRID,; ALBERTINI EMIDIO; ECHENIQUE VIVIANA C

PLOS ONE

PUBLIC LIBRARY SCIENCE

Lugar: San Francisco; Año: 2017

1932-6203

To overcome environmental stress, plants develop physiological responses that aretriggered by genetic or epigenetic changes, some of which involve DNA methylation. Ithas been proposed that apomixis, the formation of asexual seeds without meiosis,occurs through the temporal or spatial deregulation of the sexual process mediated bygenetic and epigenetic factors influenced by the environment. Here, we exploredwhether there was a link between the occurrence of apomixis and various factors thatgenerate genomic stress, including drought stress, in vitro culture, and intraspecifichybridization. For this purpose, we monitored the embryo sacs of different weepinglovegrass (Eragrostis curvula [Schrad.] Nees) genotypes after the plants weresubjected to these stress conditions. Progeny tests based on molecular markers andgenome methylation status were also carried out following the stress treatment. Whengrown in the greenhouse, the cultivar Tanganyika INTA generated less than 2% of itsprogeny by sexual reproduction. Plants of this cultivar subjected to different stressesshowed an increase of sexual embryo sacs, demonstrating an increased expression ofsexuality compared to control plants. Plants of the cv. Tanganyika USDA did notdemonstrate the ability to generate sexual embryo sacs under any conditions and istherefore classified as a fully apomictic cultivar. We found that this change in theprevalence of sexuality was related to genetic and epigenetic changes. Our resultsdemonstrate that different stress conditions can alter the choice of reproductive modein facultative tetraploid cultivars and when the stress stops the reproductive mode shiftback to apomixis original level. These data together with previous observations allowus to generate a hypothetical model of the regulation of apomixis in weeping lovegrassin which the genetic/s region/s that condition apomixis, is/are affected by ploidy, andare subjected to epigenetic control.