biostudies-literatureUnknown13Tian ZTrigenomic <i>Brassica</i> allohexaploids (AABBCC, 2n = 6x = 54) have great potential in oilseed breeding and genetic diversity. However, <i>Brassica</i> allohexaploids do not exist naturally, and the underlying mechanism regulating pollen fertility in artificially synthesized <i>Brassica</i> allohexaploids is still unclear. In this study, synthetic <i>Brassica</i> allohexaploids were produced by crossing allotetraploid <i>B. carinata</i> (BBCC, 2n = 4x = 34) and diploid <i>B. rapa</i> (AA, 2n = 2x = 20), followed by chromosome doubling. The results showed that the pollen fertility was significantly reduced and the pollen structures were mostly distorted, but the nursing anther tapetum developed normally in the synthetic <i>Brassica</i> allohexaploids. Furthermore, the data showed that the meiotic events occurred irregularly with uneven chromosome segregation and microspore development appeared mostly abnormal. Transcription analysis showed that the upregulation of genes related to the negative regulation of flower development and the downregulation of genes related to chromosome segregation might play an essential role in reduction of pollen fertility in the <i>Brassica</i> allohexaploids. In conclusion, this study elucidated the related mechanisms affecting pollen fertility during male gametophytic development at the cytological and transcriptomic levels in the newly synthesized <i>Brassica</i> allohexaploids.Frontiers in plant science1096804https://www.ebi.ac.uk/biostudies/studies/S-EPMC9880477biostudies-literatureIntegrated cytological and transcriptomic analysis reveals insights into pollen fertility in newly synthetic <i>Brassica</i> allohexaploids.PMC9880477Tian ZJi CYang YCao GXie ZTian BWei FShi GWei XShi XfalseIntegrated cytological and transcriptomic analysis reveals insights into pollen fertility in newly synthetic <i>Brassica</i> allohexaploids.Trigenomic <i>Brassica</i> allohexaploids (AABBCC, 2n = 6x = 54) have great potential in oilseed breeding and genetic diversity. However, <i>Brassica</i> allohexaploids do not exist naturally, and the underlying mechanism regulating pollen fertility in artificially synthesized <i>Brassica</i> allohexaploids is still unclear. In this study, synthetic <i>Brassica</i> allohexaploids were produced by crossing allotetraploid <i>B. carinata</i> (BBCC, 2n = 4x = 34) and diploid <i>B. rapa</i> (AA, 2n = 2x = 20), followed by chromosome doubling. The results showed that the pollen fertility was significantly reduced and the pollen structures were mostly distorted, but the nursing anther tapetum developed normally in the synthetic <i>Brassica</i> allohexaploids. Furthermore, the data showed that the meiotic events occurred irregularly with uneven chromosome segregation and microspore development appeared mostly abnormal. Transcription analysis showed that the upregulation of genes related to the negative regulation of flower development and the downregulation of genes related to chromosome segregation might play an essential role in reduction of pollen fertility in the <i>Brassica</i> allohexaploids. In conclusion, this study elucidated the related mechanisms affecting pollen fertility during male gametophytic development at the cytological and transcriptomic levels in the newly synthesized <i>Brassica</i> allohexaploids.2022-01-01T00:00:00Z20222024-12-03T23:00:27.102Z2024-12-03T23:00:27.102ZS-EPMC98804773671474410.3389/fpls.2022.1096804