Dmc1 is a candidate for temperature tolerance during wheat meiosis

Abstract

Key message The meiotic recombination gene Dmc1 on wheat chromosome 5D has been identified as a candidate for the maintenance of normal chromosome synapsis and crossover at low and possibly high temperatures. Abstract We initially assessed the effects of low temperature on meiotic chromosome synapsis and crossover formation in the hexaploid wheat (Triticum aestivum L.) variety 'Chinese Spring'. At low temperatures, asynapsis and chromosome univalence have been observed before in Chinese Spring lines lacking the long arm of chromosome 5D (5DL), which led to the proposal that 5DL carries a gene (Ltp1) that stabilises wheat chromosome pairing at low temperatures. In the current study, Chinese Spring wild type and 5DL interstitial deletion mutant plants were exposed to low temperature in a controlled environment room during a period from premeiotic interphase to early meiosis I. A 5DL deletion mutant was identified whose meiotic chromosomes exhibit extremely high levels of asynapsis and chromosome univalence at metaphase I after 7 days at 13 °C, suggesting that Ltp1 is deleted in this mutant. Immunolocalisation of the meiotic proteins ASY1 and ZYP1 on ltp1 mutants showed that low temperature results in a failure to complete synapsis at pachytene. KASP genotyping revealed that the ltp1 mutant has a 4-Mb deletion in 5DL. Of 41 genes within this deletion region, the strongest candidate for the stabilisation of chromosome pairing at low temperatures is the meiotic recombination gene Dmc1. The ltp1 mutants were subsequently treated at 30 °C for 24 h during meiosis and exhibited a reduced number of crossovers and increased univalence, though to a lesser extent than at 13 °C. We therefore renamed our ltp1 mutant 'ttmei1' (temperature-tolerant meiosis 1) to reflect this additional loss of high temperature tolerance.

Heat stress interferes with chromosome segregation and cytokinesis during male meiosis inArabidopsis thaliana

“…9,[46][47][48] In wheat, high temperature has been shown to induce a significantly increased number of univalent and irregularities in chromosome alignment at metaphase Ι, and DMC1 was proposed to mediate the heat tolerance. 49 It is possible that heat stress predominantly interferes with DSB repair and meiotic recombination during male meiosis. To this end, a detection of recombinases DMC1 and RAD51 should be applied in future study.…”

Characterization of germline development and identification of genes associated with germline specification in pineapple

“…6 ). However, DMC1 in wheat was previously reported to maintain normal chromosome synapsis and crossover during later stages of meiosis 69 , and the analysis of OsDMC1-RNAi lines demonstrated that OsDMC1 was essential for rice homologous pairing 70 . These findings suggest that gene expression during meiosis is intricately regulated spatially and temporally, which might be critical for ensuring that the chronology of meiosis meiotic events proceeds properly in the subsequent stages.…”

The Formation of Bivalents and the Control of Plant Meiotic Recombination

“…These single ends can invade homologous sequences (process called single-end invasion or SEI) thanks to the recombinase activities of RAD51 and DMC1 ( Couteau et al, 1999 ; Li et al, 2004 ). These recombinases have the properties to form a strong homology-based DNA triple helix called a displacement loop (D-loop) ( Kurzbauer et al, 2012 ; Wang et al, 2016 ; Singh et al, 2017 ; Colas et al, 2019 ; Draeger et al, 2020 ). The RAD51 and DMC1 are part of the same recombinase protein family also containing RAD51C and XRCC3 that derive from the same ancestor but have undergone subfunctionalization ( Bleuyard et al, 2004 ; Da Ines et al, 2013 ; Pradillo et al, 2014 ).…”