Understanding a Gene Linked to Male Sterility in Flowering Chinese Cabbage

Greg Howard
23rd May, 2024

Understanding a Gene Linked to Male Sterility in Flowering Chinese Cabbage

Image Source: Natural Science News, 2024

Key Findings

  • The study focused on a male-sterile line of flowering Chinese cabbage, which can produce a completely sterile population
  • Researchers identified the male-sterile gene within a 185 kb region on chromosome A07 in Brassica rapa var. Chiifu-401
  • Significant structural variations were found in this region, but no sequence differences in the Bnams4b gene were detected between sterile and fertile plants, suggesting further research is needed
Brassica vegetables, known for their pronounced heterosis, have been the focus of numerous studies due to their agricultural significance. However, investigations on fertility-related genes in these plants are relatively scarce. A recent study by the Guangdong Academy of Agricultural Sciences[1] delves into a recessive genic male-sterile line, 7-3A, which can produce a completely sterile population. This discovery holds significant promise for the breeding of flowering Chinese cabbage. The study employed whole-genome resequencing of both sterile and fertile plants to identify the male-sterile gene. The gene was confined to a region of approximately 185 kb on chromosome A07, located between markers C719 and NP10 in Brassica rapa var. Chiifu-401. Notably, substantial structural variation was identified within this region across diverse Brassica rapa reference genomes. Despite observable differences in the expression levels of a homologous gene, Bnams4b, between male sterile and fertile plants, no sequence divergence was detected. This indicates that further research is needed to pinpoint the novel sterile gene within the candidate interval. This study builds on previous findings related to Brassica species. For instance, a prior study on Brassica rapa highlighted the impact of whole-genome triplication (WGT) on intraspecific diversification[2]. The WGT event led to an accumulation of transposable elements and non-synonymous mutations in certain genes, termed "flexible" genes. These flexible genes, which are biased towards more fractionated subgenomes, play a role in the plant's response to environmental stimuli and may contribute to adaptation. The current study's identification of structural variation within the candidate region on chromosome A07 aligns with the earlier observation that structural variations can influence important traits, such as fertility. Additionally, the discovery of the male-sterile gene in Brassica rapa var. Chiifu-401 echoes previous research on male sterility in Brassica napus. For example, a study on the BnRf locus in Brassica napus revealed the complex organization of this region and its role in male sterility[3]. The BnRf locus includes multiple alleles, and the male sterility in certain lines was found to be conferred by specific alleles. The current study's focus on structural variation within a candidate region for male sterility in Brassica rapa suggests a similar complexity in the genetic basis of sterility in this species. Moreover, the recent study's findings on the expression level disparities of Bnams4b between sterile and fertile plants are reminiscent of another study on the role of the BnaC.Tic40 gene in tapetal development and male sterility in Brassica napus[4]. The BnaC.Tic40 gene, which is highly expressed in the tapetum, is crucial for proper tapetal function and lipid accumulation. The absence of this gene in a male sterile mutant led to abnormal tapetal development and sterility. The current study's observation of expression level differences in Bnams4b suggests that similar regulatory mechanisms may be at play in Brassica rapa. In conclusion, the study by the Guangdong Academy of Agricultural Sciences provides valuable insights into the genetic basis of male sterility in Brassica rapa and has significant implications for the breeding of flowering Chinese cabbage. By identifying structural variation within a candidate region on chromosome A07 and highlighting expression level disparities of a homologous gene, this research advances our understanding of male sterility mechanisms and contributes to the development of molecular-assisted breeding strategies. The findings also tie together previous studies on the genetic and structural complexities underlying male sterility in Brassica species, further enriching our knowledge of plant reproductive biology.

VegetablesGeneticsPlant Science

References

Main Study

1) Genetic characterization and fine mapping of a recessive genic male-sterile gene in flowering Chinese cabbage (Brassica rapa var. parachinensis).

Published 23rd May, 2024

https://doi.org/10.1007/s13205-024-04005-7

Related Studies

2) Impacts of allopolyploidization and structural variation on intraspecific diversification in Brassica rapa.

https://doi.org/10.1186/s13059-021-02383-2

3) Map-based cloning reveals the complex organization of the BnRf locus and leads to the identification of BnRf(b), a male sterility gene, in Brassica napus.

https://doi.org/10.1007/s00122-015-2608-8

4) BnaC.Tic40, a plastid inner membrane translocon originating from Brassica oleracea, is essential for tapetal function and microspore development in Brassica napus.

https://doi.org/10.1111/j.1365-313X.2011.04708.x


Related Articles

An unhandled error has occurred. Reload 🗙