The role of mir160 and arf10 in the auxin-mediated plant reproduction control.

PESSINO, SILVINA; COLONO, CAROLINA; AZZARO, CELESTE; COSTANTINI, ELENA; COLOMBO, LUCIA; MENDES, MARTA

Mendoza

Congreso; XVII Congreso Latinoamericano de Genética; 2019

Sociedad Argentina de Genética

Apomixis (asexual reproduction via seeds) is considered an evolutionary deviation from sexuality,caused by genetic/epigenetic variations involving one or several developmental genes. However, recent evidence suggested that both reproductive modes are anciently polyphenic and the transition from one to the other can be triggered by environmental signals. In previous comparative transcriptome analyses, we determined that the auxin-controlled genes miR160 and ARF10 (one of the miR160 targets) display up- and down-regulation, respectively, in apomictic plants with respect to sexual ones. The objective of this work was to explore a hypothetical miRNA160/ARF10 reproductive function in the Arabidopsis thaliana sexual model. Analysis of pARF10:ARF10-GFP lines revealed expression in a single cell layer surrounding the megaspore mother cell (MMC). An ARF10 defective line carrying a 5?UTR-located T insertion showed a 3-fold gene expression reduction, ovule abortion and MMC delayed entrance into meiosis. ARF10 x pKNU-GFP crosses displayed a significant reduction of KNU expression within MMCs, suggesting differentiationalterations. miRNA160-insensitive pARF10::ARF10- GFP lines showed ARF10 expression across theentire ovule, pointing to a miRNA160-directed ARF10 silencing in MMCs, nucella and integuments.The same lines showed multiple MMCs, reduced megaspores, and mature embryo sacs per ovule.We concluded that the ARF10 spatial pattern of expression in the ovule is determined by the activitymiRNA160 and essential to the onset of meiosis.