Defects in meiotic chromosome segregation lead to unreduced male gametes in Arabidopsis SMC5/6 complex mutants

Structural maintenance of chromosome 5/6 (SMC5/6) complex is a crucial factor for preserving genome stability. Here, we show that mutants for several Arabidopsis (Arabidopsis thaliana) SMC5/6 complex subunits produce triploid offspring. This phenotype is caused by a meiotic defect leading to the pro...

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Bibliographic Details
Published in:The Plant cell 2021-09, Vol.33 (9), p.3104-3119
Main Authors: Yang, Fen, Fernández-Jiménez, Nadia, Tučková, Martina, Vrána, Jan, Cápal, Petr, Díaz, Mariana, Pradillo, Mónica, Pecinka, Ales
Format: Article
Language:English
Subjects:
Arabidopsis - genetics
Arabidopsis - growth & development
Arabidopsis Proteins - genetics
Arabidopsis Proteins - metabolism
Chromosome Segregation
DNA Breaks, Double-Stranded
Meiosis
Pollen - genetics
Pollen - growth & development
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Summary:Structural maintenance of chromosome 5/6 (SMC5/6) complex is a crucial factor for preserving genome stability. Here, we show that mutants for several Arabidopsis (Arabidopsis thaliana) SMC5/6 complex subunits produce triploid offspring. This phenotype is caused by a meiotic defect leading to the production of unreduced male gametes. The SMC5/6 complex mutants show an absence of chromosome segregation during the first and/or the second meiotic division, as well as a partially disorganized microtubule network. Importantly, although the SMC5/6 complex is partly required for the repair of SPO11-induced DNA double-strand breaks, the nonreduction described here is SPO11-independent. The measured high rate of ovule abortion suggests that, if produced, such defects are maternally lethal. Upon fertilization with an unreduced pollen, the unbalanced maternal and paternal genome dosage in the endosperm most likely causes seed abortion observed in several SMC5/6 complex mutants. In conclusion, we describe the function of the SMC5/6 complex in the maintenance of gametophytic ploidy in Arabidopsis.
ISSN:1040-4651
1532-298X
DOI:10.1093/plcell/koab178