Zou Yang, Wan Linrong, Luo Jie, Tang Zongxiang, Fu Shulan
College of Agronomy, Sichuan Agricultural University, Wenjiang, 611130, Sichuan, China.
Institute of Ecological Agriculture, Sichuan Agricultural University, Wenjiang, 611130, Sichuan, China.
BMC Plant Biol. 2021 Apr 6;21(1):167. doi: 10.1186/s12870-021-02947-1.
DNA sequence composition affects meiotic recombination. However, the correlation between tandem repeat composition and meiotic recombination in common wheat (Triticum aestivum L.) is unclear.
Non-denaturing fluorescent in situ hybridization (ND-FISH) with oligonucleotide (oligo) probes derived from tandem repeats and single-copy FISH were used to investigate recombination in three kinds of the long arm of wheat 5A chromosome (5AL). 5AL arm carries the tandem repeats pTa-535, Oligo-18, and pTa-275, 5AL arm carries the tandem repeats pSc119.2, Oligo-18 and pTa-275, and 5AL arm carries the tandem repeats pSc119.2. In the progeny of 5AL × 5AL, double recombination occurred between pSc119.2 and pTa-535 clusters (119-535 interval), and between pTa-535 and Oligo-18/pTa-275 clusters (535-18 interval). The recombination rate in the 119-535 interval in the progeny of 5AL × 5AL was higher than that in the progeny of 5AL × 5AL. Recombination in the 119-535 interval produced 5AL segments with pTa-535 and pSc119.2 tandem repeats and 5AL segments without these repeats. The 5AL and 5AL segments were localized between the signal sites of the single-copy probes SC5A-479 and SC5A-527. The segment between SC5A-479 and SC5A-527 in the metaphase 5AL was significantly longer than that in the metaphase 5AL.
The structural variations caused by tandem repeats might be one of the factors affecting meiotic recombination in wheat. Meiotic recombination aggregated two kinds of tandemly repeated clusters into the same chromosome, making the metaphase chromosome more condensed. To conclude, our study provides a robust tool to measure meiotic recombination and select parents for wheat breeding programs.
DNA序列组成会影响减数分裂重组。然而，普通小麦（Triticum aestivum L.）中串联重复序列组成与减数分裂重组之间的相关性尚不清楚。
使用源自串联重复序列的寡核苷酸（oligo）探针进行非变性荧光原位杂交（ND-FISH）以及单拷贝FISH，来研究小麦5A染色体长臂（5AL）的三种类型中的重组情况。5AL臂携带串联重复序列pTa-535、Oligo-18和pTa-275，5AL臂携带串联重复序列pSc119.2、Oligo-18和pTa-275，5AL臂携带串联重复序列pSc119.2。在5AL×5AL的子代中，双重组发生在pSc119.2和pTa-535簇之间（119 - 535区间），以及pTa-535和Oligo-18/pTa-275簇之间（535 - 18区间）。5AL×5AL子代中119 - 535区间的重组率高于5AL×5AL子代中的重组率。119 - 535区间的重组产生了带有pTa-535和pSc119.2串联重复序列的5AL片段以及没有这些重复序列的5AL片段。5AL和5AL片段定位于单拷贝探针SC5A-479和SC5A-527的信号位点之间。中期5AL中SC5A-479和SC5A-527之间的片段明显长于中期5AL中的片段。
串联重复序列引起的结构变异可能是影响小麦减数分裂重组的因素之一。减数分裂重组将两种串联重复簇聚集到同一条染色体上，使中期染色体更加浓缩。总之，我们的研究为测量减数分裂重组和为小麦育种计划选择亲本提供了一个强大的工具。
