Meiocyte size is a determining factor for unreduced gamete formation in Arabidopsis thaliana

Abstract

Polyploidy, the presence of more than two sets of chromosomes within a cell, is a widespread phenomenon in plants. The main route to polyploidy is considered through the production of unreduced gametes that are formed as a consequence of meiotic defects. Nevertheless, for reasons poorly understood, the frequency of unreduced gamete formation differs substantially among different plant species. The previously identified meiotic mutant jason (jas) in Arabidopsis thaliana forms about 60% diploid (2n) pollen. JAS is required to maintain an organelle band as a physical barrier between the two meiotic spindles, preventing previously separated chromosome groups from uniting into a single cell.In this study, we characterized the jas suppressor mutant telamon (tel) that restored the production of haploid pollen in the jas background.The tel mutant did not restore the organelle band, but enlarged the size of male jas tel meiocytes, suggesting that enlarged meiocytes can bypass the requirement of the organelle band. Consistently, enlarged meiocytes generated by a tetraploid jas mutant formed reduced gametes.The results reveal that meiocyte size impacts chromosome segregation in meiosis II, suggesting an alternative way to maintain the ploidy stability in meiosis during evolution.

Comparative transcriptome analysis provides insights into molecular pathway and genes associated with head-type formation and phenotypic divergence in Chinese cabbage

“…2n gametes can be used in plant polyploid breeding. At present, 2n gametes have been extensively studied, such as in Chinese cabbage ( Zhang et al, 2009 ), potato ( Peloquin et al, 2008 ), kiwi ( Seal et al, 2012 ), sorghum ( Hodnett et al, 2019 ), Arabidopsis ( Yi et al, 2023 ), eggplant ( Carputo, 2003 ), and carnation ( Zhou et al, 2015 ; Zhou et al, 2022 ). 2n gametes can be utilized to produce new polyploid resources.…”

Ultraviolet attenuates centromere-mediated meiotic genome stability and alters gametophytic ploidy consistency in flowering plants

“…Arabidopsis ( Arabidopsis thaliana ) ecotype Columbia (Col-0) was used as the wild-type. The qrt (Francis et al, 2006), atm-2 (Kurzbauer et al, 2021), atr (Wang et al, 2021a), rfc1 (Yu et al, 2012), xip-101 (Fan et al, 2022), ku70 (Riha et al, 2002), sog1 (Wang et al, 2022a), tdf1 (Tidy et al, 2022), ams (Tidy et al, 2022), jason (Yi et al, 2023), cenh3-8 (Wang et al, 2023) and uvr8 (Huang et al, 2014) mutants, the fluorescent-tagged line (FTL) I3bc (Francis et al, 2007), pCENH3::RFP-CENH3 (Komaki et al, 2020), pUBQ10::GFP-ABD2-GFP (Dyachok et al, 2014), pMAP65-3::GFP-MAP65-3 (Sofroni et al, 2020) and the pAMS::AMS-GFP (Xiong et al, 2016) reporter lines were used in this study. The pMMD1::GUS-GFP reporter line was newly generated.…”