The Rice AAA-ATPase OsFIGNL1 Is Essential for Male Meiosis

Abstract

Meiosis is crucial in reproduction of plants and ensuring genetic diversity. Although several genes involved in homologous recombination and DNA repair have been reported, their functions in rice (Oryza sativa) male meiosis remain poorly understood. Here, we isolated and characterized the rice OsFIGNL1 (OsFidgetin-like 1) gene, encoding a conserved AAA-ATPase, and explored its function and importance in male meiosis and pollen formation. The rice Osfignl1 mutant exhibited normal vegetative growth, but failed to produce seeds and displayed pollen abortion phenotype. Phenotypic comparisons between the wild-type and Osfignl1 mutant demonstrated that OsFIGNL1 is required for anther development, and that the recessive mutation of this gene causes male sterility in rice. Complementation and CRISPR/Cas9 experiments demonstrated that wild-type OsFIGNL1 is responsible for the male sterility phenotype. Subcellular localization showed that OsFIGNL1-green fluorescent protein was exclusively localized in the nucleus of rice protoplasts. Male meiosis in the Osfignl1 mutant exhibited abnormal chromosome behavior, including chromosome bridges and multivalent chromosomes at diakinesis, lagging chromosomes, and chromosome fragments during meiosis. Yeast two-hybrid assays demonstrated OsFIGNL1 could interact with RAD51A1, RAD51A2, DMC1A, DMC1B, and these physical interactions were further confirmed by BiFC assay. Taken together, our results suggest that OsFIGNL1 plays an important role in regulation of male meiosis and anther development.

Unleashing meiotic crossovers in crops

“…However in Arabidopsis, further increases were obtained by combining the recq4 mutation with either a mutation in the FIGL1 gene, or with overexpression of HEI10 2,10 . While figl1 only mildly affects fertility in Arabidopsis, it leads to sterility in rice 15 and pea, precluding the use of figl1 to manipulate recombination in those species. Both figl1 mutation and HEI10 overexpression remain to be tested in other species.…”

“…Mutation in FIGL1 alone leads to a relatively modest increase in recombination (+25% in Arabidopsis hybrids), but when combined with recq4 2 it leads to an almost eight-fold increase. Mutation in FIGL1 leads to full sterility in rice 15 , raising doubts about the pertinence of manipulating this gene in crop species.…”

TDR INTERACTING PROTEIN 3, encoding a PHD‐finger transcription factor, regulates Ubisch bodies and pollen wall formation in rice

“…Anthers of wild‐type and tip3 mutants at all developmental stages were collected in liquid nitrogen (Zhang et al ., 2017b). Total RNA was isolated and cDNA was synthesized as reported previously (Yang et al ., ).…”

Maize Genic Male-Sterility Genes and Their Applications in Hybrid Breeding: Progress and Perspectives

“…The three cluster IV genes are expressed highly at both stages 6 and 8b/9 and are maize orthologs of OsABCG26 (Chang et al, 2016b), EAT1/DTD (Niu et al, 2013), and CAP1 (Ueda et al, 2013) in rice. The 18 cluster V genes are expressed constitutively during all the six anther stages and are maize orthologs of NPU (Chang et al, 2012), AtGPAT6 (Li et al, 2012), FLP1/WAX2, MYB33 (Millar and Gubler, 2005), RBOHE, NEF1 (Ariizumi et al, 2004), TGA9, and EMS1/EXS in Arabidopsis, and API5 (Li et al, 2011b), OsDEX1 (Yu et al, 2016), DTM1 (Yi et al, 2012), OsGT1 (Moon et al, 2013b), GAMYB (Aya et al, 2009), CSA (Zhang et al, 2010b), and OsFIGNL1 (Zhang et al, 2017) in rice. However, the other 18 maize orthologs in cluster VI are barely expressed at all six stages, and are not likely to be GMS genes in maize.…”