A lignified-layer bridge controlled by a single recessive gene is associated with high pod-shatter resistance in Brassica napus L.

Pod shattering causes severe yield loss in rapeseed (Brassica napus L.) under modern agricultural practice. Identification of highly shatter-resistant germplasm is desirable for the development of rapeseed cultivars for mechanical harvesting. In the present study, an elite line OR88 with strong shatter resistance and a lignified-layer bridge (LLB) structure was identified. The LLB structure was unique to OR88 and co-segregated with high pod-shatter resistance. The LLB structure is differentiated at stage 12 of gynoecium development without any gynoecium defects. Genetic analysis showed that LLB is controlled by a single recessive gene. By BSA-Seq and map-based cloning, the resistance gene location was delimited to a 0.688 Mb region on chromosome C09. Transcriptome analysis suggested BnTCP8.009 as the gene responsible for LLB. The expression of BnTCP.009 was strongly downregulated in OR88, suppressing cell proliferation in the pod valve margin. KASP markers linked to the candidate gene were developed. This pod shatter-resistant line could be used in rapeseed breeding programs by direct transfer of the gene with the assistance of the DNA markers. (C) 2021 Crop Science Society of China and Institute of Crop Science, CAAS. Production and hosting by Elsevier B.V. on behalf of KeAi Communications Co., Ltd.

Automated summary

In this study, an elite line OR88 with strong shatter resistance and a lignified-layer bridge (LLB) structure was identified in rapeseed. The LLB structure was controlled by a single recessive gene and the gene responsible for LLB was identified as BnTCP8.009. Genetic markers linked to the candidate gene were developed. This finding provides valuable insights for the development of shatter-resistant rapeseed cultivars.