FANCM suppresses crossovers in plants by unwinding recombination intermediates. In wheat, crossovers are skewed toward the chromosome ends, thus limiting generation of novel allelic combinations. Here, we observe that FANCM maintains the obligate crossover in tetraploid and hexaploid wheat, thus ensuring that every chromosome pair exhibits at least one crossover, by localizing class I crossover protein HEI10 at pachytene. FANCM also suppresses class II crossovers that increased 2.6-fold in fancm msh5 quadruple mutants. These data are consistent with a role for FANCM in second-end capture of class I designated crossover sites, whilst FANCM is also required to promote formation of non-crossovers. In hexaploid wheat, genetic mapping reveals that crossovers increase by 31% in fancm compared to wild type, indicating that fancm could be an effective tool to accelerate breeding. Crossover rate differences in fancm correlate with wild type crossover distributions, suggesting that chromatin may influence the recombination landscape in similar ways in both wild type and fancm.

FANCM 通过展开重组中间体来抑制植物中的交叉。在小麦中，交叉向染色体末端倾斜，从而限制了新等位基因组合的产生。在这里，我们观察到 FANCM 在四倍体和六倍体小麦中保持专性交叉，从而通过将 I 类交叉蛋白 HEI10 定位在粗线期来确保每个染色体对都表现出至少一个交叉。FANCM 还抑制在fancm msh5四倍突变体中增加 2.6 倍的 II 类交叉。这些数据与 FANCM 在 I 类指定交叉位点的第二端捕获中的作用一致，而 FANCM 也需要促进非交叉点的形成。在六倍体小麦中，遗传图谱显示交叉在fancm中增加了 31%与野生型相比，表明fancm可以成为加速育种的有效工具。fancm的交叉率差异与野生型交叉分布相关，表明染色质可能以相似的方式影响野生型和fancm的重组景观。