Operation of the Paspalum notatum sexuality-apomixis switch by PN_TGS1-LIKE and other members of the splicing machinery

ORTIZ JPA; PERMINGEAT, HUGO; COLONO CM; LEBLANC, OLIVIER; PESSINO SC; SIENA LA; SOUZA CANADA ED

Workshop; Workshop Advances in Apomixis Research; 2018

Paspalum notatum is a grass species that form aposporous pseudogamous self-fertile tetraploid cytotypes. Aposporous apomictic plants form maternal seeds by inducing the appearance non-reduced embryo sacs in the ovule nucellus and the development of embryos by parthenogenesis. P. notatum present a plant-specific gene TRIMETHYLGUANOSINE SYNTHASE 1 (TGS1) named PN_TGS1-like. PN_TGS1-like is overexpressed in nucellar cells of sexual biotypes with respect to apomictic ones. Furthermore, PN_TGS1-like expression positively correlated with the rate of sexuality in obligate and embryo sac per ovule. Morever, antisense lines developed long trichomes in the adaxial surface of leaves and produced a similar amount of viable pollen with respect a control plant. Flow cytometry facultative biotypes.Our objective was to study the role of PN_TGS1-like gene in the sexuality-apomixis transition. Undifferentiated calli originated from sexual plant were transformed with a PN_TGS1-like antisense construct. Antisense lines with a reduced PN_TGS1-like expression in both leaves and flowers were obtained. Downregulation of PN_TGS1-like allowed the emergence of multiple embryo sac within the same ovary, with an aposporous-like morphology (AES-like). While Antisense lines had 13-16% ovules bearing AES-like, transformation control and wild type presented a single meiotic analysis of seeds revealed that only the sexual reproductive pathway is present in both control and transgenic plants. However, we observed the form of aposporous initials cells in antisense lines. Our results show that PN_ TGS1-like inhibits the formation of multiple embryo sacs in sexual ovules. Antisense lines produce non-reduced embryo sacs in the nucellus but do not produce apomictic seed development, which indicates that AES-like sacs are not capable to carry on parthenogenesis.