Genetic Cause of Male Sterility in Chinese Cabbage Discovered

Jenn Hoskins
3rd March, 2024

Genetic Cause of Male Sterility in Chinese Cabbage Discovered

Image Source: Natural Science News, 2024

Key Findings

  • Scientists identified a gene, BrABCG26, causing male sterility in Chinese cabbage
  • Mutations in BrABCG26 disrupt pollen development, preventing the plant from reproducing
  • This discovery aids breeders in creating high-yield, disease-resistant hybrid cabbages
In the quest to enhance the production of Chinese cabbage, a recent study by scientists at Shenyang Agricultural University[1] has pinpointed a specific gene responsible for male sterility in this vegetable. Male sterility in plants is a crucial trait for breeders, as it facilitates the production of hybrid seeds, which can lead to crops with superior qualities such as greater yields, resistance to diseases, and better stress tolerance. The study identified two mutant strains of Chinese cabbage, msm3-1 and msm3-2, which exhibited complete degeneration of stamens and lacked pollen, while other characteristics remained unchanged compared to the normal 'FT' Chinese cabbage line. The absence of viable pollen makes these plants male sterile, a condition where a plant cannot produce or release functional male gametes, the pollen grains. Upon closer examination, the researchers discovered that the failure of microspores, the cells that develop into pollen grains, to undergo a critical stage called vacuolation, along with abnormal degradation of the tapetum (the nutrient-rich layer that supports pollen development), led to the failure of anther development. The anther is the part of the stamen where pollen is produced. Genetic analysis revealed that the male sterility trait in these mutants was controlled by a recessive gene. Using a technique called MutMap, combined with a precise genotyping method known as kompetitive allele specific PCR, the team was able to pinpoint the gene responsible for this trait, which they named BrABCG26. This gene encodes a protein that functions as a transporter, playing a vital role in the formation of the pollen wall, a structure that protects pollen grains and is essential for their viability. The researchers found mutations in two different locations of the BrABCG26 gene in the two mutants. These mutations resulted in the production of a truncated, non-functional version of the transporter protein. This loss of function confirmed the role of BrABCG26 in stamen and pollen development. Further investigations showed that BrABCG26 is present in all organs of the plant but is most highly expressed in flower buds. In the mutant strains, expression of BrABCG26 was significantly reduced in flower buds and anthers. Subcellular localization studies revealed that the protein is found in the nucleus, which is consistent with its role as a regulator of pollen wall formation. This discovery builds on previous research that has explored the genetic underpinnings of plant reproductive development. For instance, the identification of the BcMF28 gene in Brassica campestris, which regulates late stamen development[2], and the Bra010198 gene in Chinese cabbage, which controls pollen exine development[3], have both provided insights into the complex processes that govern male fertility in plants. Similarly, research on OsPKS2 in rice[4] has contributed to our understanding of the biosynthesis of sporopollenin, a key component of the pollen wall. The findings of the Shenyang Agricultural University study not only advance our knowledge of the genetic mechanisms that lead to male sterility in Chinese cabbage but also have practical implications for breeding programs. By manipulating the BrABCG26 gene, breeders can develop male-sterile lines more efficiently, which is a critical step in producing hybrid seeds. This can ultimately lead to the creation of new varieties of Chinese cabbage with improved qualities, benefiting both farmers and consumers. The research also demonstrates the power of modern genetic tools in pinpointing the exact genetic mutations responsible for desirable traits in crops. This precision can accelerate the breeding process and allow for the rapid development of new plant varieties to meet the demands of a growing global population.

VegetablesGeneticsPlant Science

References

Main Study

1) Mutations in BrABCG26, encoding an ATP-binding cassette transporter, are responsible for male sterility in Chinese cabbage (Brassica rapa L. ssp. pekinensis).

Published 1st March, 2024

https://doi.org/10.1007/s00122-024-04573-5

Related Studies

2) Overexpression of a stamen-specific R2R3-MYB gene BcMF28 causes aberrant stamen development in transgenic Arabidopsis.

https://doi.org/10.1016/j.bbrc.2019.08.119

3) Mapping of the male sterile mutant gene ftms in Brassica rapa L. ssp. pekinensis via BSR-Seq combined with whole-genome resequencing.

https://doi.org/10.1007/s00122-018-3223-2

4) OsPKS2 is required for rice male fertility by participating in pollen wall formation.

https://doi.org/10.1007/s00299-018-2265-x


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