Assessment of the roles of SPO11-2 and SPO11-4 in meiosis in rice using CRISPR/Cas9 mutagenesis. (26th August 2020)

• Record Type: Journal Article
• Authors: Fayos, Ian; Meunier, Anne Cécile; Vernet, Aurore; Navarro-Sanz, Sergi; Portefaix, Murielle; Lartaud, Marc; Bastianelli, Giacomo; Périn, Christophe; Nicolas, Alain; Guiderdoni, Emmanuel
• Editors: Wilson, Zoe
• Is Part Of: Journal of experimental botany. Volume 71:Number 22(2020)
• Page Start: 7046
• Page End: 7058
• Publication Date: 2020-08-26
• Subjects: CRISPR/Cas9 mutagenesis -- meiosis -- recombination -- rice -- SPO11; Botany -- Periodicals; Botany, Experimental -- Periodicals; Plant physiology -- Periodicals; 580
• DOI: 10.1093/jxb/eraa391
• Languages: English
• ISSNs: 0022-0957

Abstract

Abstract: In Arabidopsis, chromosomal double-strand breaks at meiosis are presumably catalyzed by two distinct SPO11 transesterases, AtSPO11-1 and AtSPO11-2, together with M-TOPVIB. To clarify the roles of the SPO11 paralogs in rice, we used CRISPR/Cas9 mutagenesis to produce null biallelic mutants in OsSPO11-1, OsSPO11-2, and OsSPO11-4 . Similar to Osspo11-1, biallelic mutations in the first exon of OsSPO11-2 led to complete panicle sterility. Conversely, all Osspo11-4 biallelic mutants were fertile. To generate segregating Osspo11-2 mutant lines, we developed a strategy based on dual intron targeting. Similar to Osspo11-1, the pollen mother cells of Osspo11-2 progeny plants showed an absence of bivalent formation at metaphase I, aberrant segregation of homologous chromosomes, and formation of non-viable tetrads. In contrast, the chromosome behavior in Osspo11-4 male meiocytes was indistinguishable from that in the wild type. While similar numbers of OsDMC1 foci were revealed by immunostaining in wild-type and Osspo11-4 prophase pollen mother cells (114 and 101, respectively), a surprisingly high number (85) of foci was observed in the sterile Osspo11-2 mutant, indicative of a divergent function between OsSPO11-1 and OsSPO11-2. This study demonstrates that whereas OsSPO11-1 and OsSPO11-2 are the likely orthologs of AtSPO11-1 and AtSPO11-2, OsSPO11-4 has no major role in wild-type rice meiosis. Abstract : Plant genomes harbor several SPO11 genes, which encode the endonuclease catalyzing DNA double-strand breaks at meiosis. While OsSPO11-2 is crucial for rice meiosis, OsSPO11-4 is dispensable.