OsMFS1/OsHOP2 Complex Participates in Rice Male and Female Development

Abstract

Meiosis plays an essential role in the production of gametes and genetic diversity of posterities. The normal double-strand break (DSB) repair is vital to homologous recombination (HR) and occurrence of DNA fragment exchange, but the underlying molecular mechanism remain elusive. Here, we characterized a completely sterile Osmfs1 (male and female sterility 1) mutant which has its pollen and embryo sacs both aborted at the reproductive stage due to severe chromosome defection. Mapbased cloning revealed that the OsMFS1 encodes a meiotic coiled-coil protein, and it is responsible for DSB repairing that acts as an important cofactor to stimulate the single strand invasion. Expression pattern analyses showed the OsMFS1 was preferentially expressed in meiosis stage. Subcellular localization analysis of OsMFS1 revealed its association with the nucleus exclusively. In addition, a yeast two-hybrid (Y2H) and pulldown assay showed that OsMFS1 could physically interact with OsHOP2 protein to form a stable complex to ensure faithful homologous recombination. Taken together, our results indicated that OsMFS1 is indispensable to the normal development of anther and embryo sacs in rice.

Curling Leaf 1, Encoding a MYB-Domain Protein, Regulates Leaf Morphology and Affects Plant Yield in Rice

“…A total of 45 clones were identified on the double-dropout medium, and sequencing analysis revealed 8 nonredundant genes. Among them, the SRS5 [50,51] and OsMFS1 [52] appeared most frequently in the clones (4 times each). SRS5 encodes an alpha-tubulin protein and regulates cell elongation, independent of the BR signaling pathway, resulting in dwarfism, twisted aboveground growth, right-handed leaf and stem spiraling, shortened but non-twisted roots, increased meristematic cell numbers at the stem tip, and abnormal leaf cell shapes [50,51].…”

“…SRS5 encodes an alpha-tubulin protein and regulates cell elongation, independent of the BR signaling pathway, resulting in dwarfism, twisted aboveground growth, right-handed leaf and stem spiraling, shortened but non-twisted roots, increased meristematic cell numbers at the stem tip, and abnormal leaf cell shapes [50,51]. The osmfs1 mutant exhibits pollen grains lacking starch granules, irregular shapes, male gametophyte sterility, and defective embryo sac development due to severe chromosomal abnormalities during the reproductive stages [52]. Therefore, these two genes were selected for pairwise verification analysis with CL1.…”

“…The bait protein vectors pGADT7-SRS5 and pGADT7-Os-MFS1 were constructed and co-transformed with the prey vector pGBKT7-CL1 into yeast cells (Figure 6B). The growth of the transformed yeast cells on the control medium (SD/LT) and selective growth medium (SD/LTHA) indicated the interaction between CL1 and SRS5 [50,51], as well as OsMFS1 [52]. The interaction between pGBKT-53 and pGADT7-T was used as the positive control; pGBKT7lam + pGADT7-T was used as the negative control.…”

Exploiting Genic Male Sterility in Rice: From Molecular Dissection to Breeding Applications

“…Finally, the gene OsMFS1 encodes for a meiotic coiled-coil protein that is essential for the formation of double-strand breaks, which plays an indispensable role in meiosis and anther development. Accordingly, mfs1 mutants produce abortive pollen with reduced sporopollenin deposition, an impaired tectum, and columella formation (abnormal exine) ( Lu et al, 2020 ).…”

The Formation of Bivalents and the Control of Plant Meiotic Recombination

“…RAD51 and DMC1 also associate with other proteins modulating their activities such as BRCA2 ( Siaud et al, 2004 ; Dray et al, 2006 ; Seeliger et al, 2012 ; Fu et al, 2020 ), FIGL1 and FLIP ( Zhang P. et al, 2017 ; Fernandes et al, 2018a ; Kumar et al, 2019 ), or MND1, and HOP2 ( Vignard et al, 2007 ; Uanschou et al, 2013 ; Aklilu et al, 2020 ). Rice MND1/MSF1 can interact with RPA2b and HOP2 ( Lu et al, 2020 ), while OsHOP2 can directly interact with the SC central element ZEP1/ZYP1 suggesting a second mechanism for the link observed between early recombination and synapsis ( Shi et al, 2019 ) at the SEI step. The excess number of SEI creating several interconnections between homologous chromosomes (also called interhomolog joint molecules) were proposed to be involved in the pairing process ( Pawlowski et al, 2003 ).…”