Nutrient Competition in Apple Blossoms Prevents Fire Blight Infection

Jenn Hoskins
21st July, 2024

Nutrient Competition in Apple Blossoms Prevents Fire Blight Infection

Image Source: Natural Science News, 2024

Key Findings

  • The study focused on apple flowers at different stages to understand microbial interactions affecting fire blight disease
  • E. amylovora uses a carbohydrate called arabinogalactan, secreted by flowers, to colonize apple flowers early
  • Pantoea agglomerans competes more effectively for arabinogalactan and suppresses E. amylovora's virulence by using arabinose
Understanding the composition of microbial communities in plants is crucial for maintaining their health and productivity. However, the factors that control these microbial communities, especially in flowers, are not well understood. A recent study by the National Institute of Agricultural Sciences[1] investigated how the floral microbiota and microbial competition affect disease development and suppression in apple flowers, specifically focusing on fire blight, a devastating bacterial disease caused by Erwinia amylovora. The researchers used apple flowers at three different flowering stages (Bud, Popcorn, and Full-bloom) to study changes in microbial flora and RNA expression patterns. They employed advanced sequencing technologies and conducted both in vitro (laboratory-based) and in vivo (real-world) experiments to validate their findings. The study revealed that E. amylovora utilizes a carbohydrate called arabinogalactan, secreted by flowers, to colonize apple flowers early. However, another bacterium, Pantoea agglomerans, was found to be more competitive for arabinogalactan than E. amylovora. Interestingly, P. agglomerans suppressed the expression of virulence factors in E. amylovora by using arabinose, a major component of arabinogalactan, which otherwise induces virulence gene expression in E. amylovora. This study builds on previous research that has explored various aspects of plant-pathogen interactions and microbial community dynamics. For instance, earlier studies have shown the importance of managing fire blight using bactericides like kasugamycin, which demonstrated high efficacy against E. amylovora[2]. However, the new study provides a different perspective by focusing on microbial competition and nutrient utilization rather than chemical treatments. Another relevant study investigated the microbiomes of apple stigmas and their interaction with E. amylovora[3]. This study found that individual flowers harbored unique microbiomes and that the presence of E. amylovora did not always lead to fire blight symptoms. The current study adds to this by identifying specific microbial interactions and nutrient competitions that can suppress the pathogen, offering new avenues for disease control. The findings also align with research on the role of surface macromolecules in plant-pollinator interactions[4]. The study on Gladiolus gandavensis revealed that arabinogalactan on the stigma surface acts as an adhesive base for pollen. Similarly, the current study found that E. amylovora uses arabinogalactan for colonization, but its virulence can be suppressed by competing bacteria that utilize the same nutrient. These insights have significant implications for developing new strategies to control plant diseases like fire blight. By understanding the role of specific nutrients and microbial competition, it may be possible to manipulate the floral microbiota to suppress pathogens naturally. This approach could reduce the reliance on chemical treatments, which often lead to issues like resistance and environmental harm[5]. In summary, the study by the National Institute of Agricultural Sciences highlights the crucial role of microbial competition and nutrient utilization in disease suppression. By identifying how Pantoea agglomerans outcompetes E. amylovora for arabinogalactan and suppresses its virulence, the research opens new avenues for controlling fire blight and potentially other plant diseases. These findings build on and complement existing research, providing a more comprehensive understanding of plant-microbe interactions and their implications for plant health.

AgricultureBiochemPlant Science

References

Main Study

1) Competition for nutrient niches within the apple blossom microbiota antagonizes the initiation of fire blight infection.

Published 19th July, 2024

https://doi.org/10.1111/nph.19971

Related Studies

2) Effectiveness of Kasugamycin Against Erwinia amylovora and its Potential Use for Managing Fire Blight of Pear.

https://doi.org/10.1094/PDIS-09-10-0679

3) Temporal and spatial dynamics in the apple flower microbiome in the presence of the phytopathogen Erwinia amylovora.

https://doi.org/10.1038/s41396-020-00784-y

4) Pollen-stigma interactions: Identification and characterization of surface components with recognition potential.

Journal: Proceedings of the National Academy of Sciences of the United States of America, Issue: Vol 76, Issue 7, Jul 1979

5) Threats to global food security from emerging fungal and oomycete crop pathogens.

https://doi.org/10.1038/s43016-020-0075-0


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