Introduction
Human domestication of crops has shaped the evolution of plants for thousands of years, selecting for traits that improve yield, quality, and adaptation. However, domestication may also have unintended consequences on the interactions between plants and their associated microorganisms, collectively known as the plant microbiome. The plant microbiome can influence various aspects of plant health and performance, such as growth, stress tolerance, and disease resistance. Therefore, understanding how domestication affects the plant microbiome is crucial for developing sustainable agricultural practices that harness the potential of beneficial microbes.
Methods
A recent study led by the University of Oxford compared the microbial communities associated with seeds of two crop species that have been domesticated independently multiple times in different regions: Phaseolus vulgaris (common bean) and Phaseolus lunatus (lima bean). The researchers used high-throughput sequencing to characterize the bacterial and fungal communities of wild and domesticated beans from Mesoamerica and South America. They also measured several seed traits that have been subject to selection during domestication, such as size, weight, shape, and mineral content.
Results
The study found that domestication had a consistent impact on the composition and diversity of the seed bacterial community across both crop species and geographic regions. Domesticated beans had lower bacterial diversity and distinct bacterial communities compared to their wild relatives. Moreover, these changes in the bacterial community were correlated with changes in seed traits, especially calcium concentration, which is known to affect seed quality and cooking properties. The fungal community, on the other hand, was less affected by domestication and more influenced by geographic factors.
Discussion
The results of this study suggest that human domestication of crops can alter the plant microbiome in a predictable way, regardless of where and how domestication took place. This implies that domesticated plants have evolved similar strategies to recruit specific microbes that may confer advantages in agricultural settings. However, these changes may also have trade-offs, such as reduced ability to associate with microbes that enhance disease resistance . Therefore, further research is needed to understand the functional implications of domestication-induced shifts in the plant microbiome and how they can be exploited to improve crop productivity and resilience.