How Tomato Domestication Reduced Helpful Soil Microbe Partnerships

Jenn Hoskins
3rd May, 2024

How Tomato Domestication Reduced Helpful Soil Microbe Partnerships

Image Source: Natural Science News, 2024

Key Findings

  • Study in Colorado shows wild tomatoes rely on soil microbes to access soil phosphorus
  • Domesticated tomatoes handle phosphorus scarcity better than wild types
  • Breeding may improve tomato use of microbes for sustainable phosphorus uptake
In the quest for sustainable agriculture, scientists have been exploring ways to optimize the use of phosphorus (P), a critical nutrient for plant growth. Phosphorus is often present in soils in a form that plants cannot readily absorb. This has led to heavy reliance on mineral fertilizers, which are not only costly but also deplete nonrenewable resources. A recent study by researchers at Colorado State University[1] investigates how the domestication and breeding of tomatoes, a globally significant crop, have influenced the plants' ability to acquire phosphorus from these less accessible sources, known as legacy phosphorus. Tomatoes have undergone extensive breeding, from their wild origins to the traditional varieties before the Green Revolution (GR), and then to the modern cultivars we see today. This breeding has focused on traits like productivity and disease resistance[2]. However, the impact of these changes on the plant's interaction with soil microbes, particularly those that help solubilize phosphorus, has been less clear. The Colorado State University study compared wild, traditional (pre-GR), and modern (post-GR) tomato plants grown in soil with high amounts of legacy P but low bioavailable P. The results showed that wild tomatoes, especially the accession LA0716 (Solanum pennellii), had a greater reliance on microbial associations in the rhizosphere—the soil zone influenced by the roots—to access phosphorus. These wild tomatoes fostered a high abundance of bacteria known to solubilize phosphorus, including those producing chelating agents which bind and make phosphorus more available, and antibiotic compounds that may protect the plant from pathogens. Interestingly, despite the high presence of these beneficial microbes, wild tomatoes showed lower biomass and greater signs of phosphorus stress compared to domesticated varieties. This indicates that while wild tomatoes have strong microbial associations for P acquisition, they may not be as efficient at utilizing the P made available. On the other hand, domesticated tomatoes, both traditional and modern, showed a greater tolerance to P deficiency, suggesting that domestication has led to a reduced dependence on microbial P solubilization while improving the plants' inherent P utilization mechanisms. This study builds on previous research that has identified the importance of microbial communities in the rhizosphere for plant nutrient uptake. Phosphate solubilizing microorganisms (PSM) have been recognized for their potential to supply phosphorus to plants sustainably, reducing the need for chemical fertilizers[3]. Moreover, recent findings have highlighted how root exudates, substances secreted by plant roots, can stimulate bacteria to release phosphorus from soil minerals[4], and how wheat breeding has impacted root traits and the assembly of rhizosphere bacterial communities[5]. The implications of the Colorado State University study are significant for sustainable agriculture. By understanding the traits that have been lost or diminished through the domestication and breeding of tomatoes, breeders can potentially reintroduce or select for these traits. This could lead to cultivars that are better at recruiting and utilizing soil microbes for phosphorus solubilization, tapping into the vast reservoirs of legacy P in soils. Such an approach could reduce the need for mineral P fertilizers, lowering costs for farmers and minimizing environmental impacts. In conclusion, the study suggests that while domestication has altered the tomato's ability to recover phosphorus through microbial associations, further breeding has not significantly changed this aspect of plant-microbe interactions. This opens up opportunities to select for traits that enhance microbial P solubilization, which may have been overlooked in previous breeding programs. Leveraging these natural plant-microbe relationships could be a key strategy in making crop production more sustainable and less dependent on nonrenewable resources.

VegetablesAgriculturePlant Science


Main Study

1) Tomato domestication rather than subsequent breeding events reduces microbial associations related to phosphorus recovery.

Published 30th April, 2024

Related Studies

2) Trait discovery and editing in tomato.

3) Plant growth promotion by phosphate solubilizing bacteria.

4) Root exudate-derived compounds stimulate the phosphorus solubilizing ability of bacteria.

5) Wheat dwarfing influences selection of the rhizosphere microbiome.

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