How Tomato Roots Evolved Unique Compounds

Jenn Hoskins
26th April, 2024

How Tomato Roots Evolved Unique Compounds

Image Source: Natural Science News, 2024

Key Findings

  • Michigan State University study found tomatoes produce protective acylsugars in roots, not just leaf hairs
  • Root acylsugars differ chemically from leaf ones, suggesting separate production pathways
  • A gene duplication event led to a new gene variant, enabling acylsugar production in tomato roots
Plants have a remarkable ability to create a diverse array of chemicals, many of which play crucial roles in their survival. These chemicals, known as specialized metabolites, can help a plant defend against pests, attract pollinators, or perform other vital functions. A recent study from Michigan State University[1] has shed new light on how plants evolve to produce these important compounds, focusing on a group of chemicals known as acylsugars. Acylsugars are oily substances found on the surfaces of plants, particularly in the Solanaceae family, which includes tomatoes and potatoes. They are primarily known for their role in defending plants against insects. Interestingly, researchers have discovered that acylsugars are not only produced in the glandular trichomes—hair-like structures on the surface of leaves—but also in the roots of cultivated tomatoes. This finding prompts questions about how plants develop the ability to synthesize these compounds in different tissues. The study explored the genetic basis of acylsugar production in tomato plants. It was found that the acylsugars in tomato roots are chemically distinct from those in the trichomes, having different sugar cores. This suggests that the plant has separate machinery for producing acylsugars in different parts of the plant. To understand this machinery, the researchers identified genes that were more active in the roots, which led to the discovery of variants, or paralogs, of genes known to be involved in acylsugar production in trichomes. One particular paralog, named SlASAT1-LIKE (SlASAT1-L), was found to be essential for the production of root acylsugars. This gene is closely related to a previously known gene responsible for acylsugar production in trichomes, ASAT1. Through genetic analysis, the team at Michigan State University provided evidence that SlASAT1-L arose from a duplication event of ASAT1. Initially, both genes were expressed in trichomes, but over time, SlASAT1-L acquired the ability to be expressed in roots. This discovery is a significant step in understanding the evolution of plant metabolism. It demonstrates how plants can diversify their chemical defenses by repurposing existing genes to produce similar compounds in different tissues. This process of gene duplication and subsequent functional divergence is a common theme in the evolution of plant secondary metabolites[2]. The findings of this study also tie into previous research on how plants tailor their defense mechanisms against specific attackers[3]. Just as wheat and maize have independently evolved mechanisms to regulate the production of benzoxazinoids, a class of compounds used in plant defense, tomato plants have evolved their acylsugar pathways to function in different tissues. Furthermore, the study contributes to our understanding of the role of biosynthetic gene clusters (BGCs) in plant metabolism. BGCs are groups of genes that work together to produce a specific chemical compound. While BGCs are known to be important in the production of certain plant metabolites, their role in the evolution of new metabolic pathways is less clear. The discovery that SlASAT1-L is nested within a known acylsugar BGC suggests that these clusters can be hotspots for the evolution of new metabolic functions. The research also complements the knowledge that plants synthesize a wide variety of volatile organic compounds, with specific functions ranging from attracting pollinators to deterring herbivores[4]. Understanding the genetic and biochemical basis of these compounds can lead to applications in agriculture, such as the development of pest-resistant crops or the use of natural plant volatiles for pest control. In conclusion, the study from Michigan State University has revealed a fascinating aspect of plant evolution. By uncovering the genetic changes that allow tomato plants to produce acylsugars in their roots, the research provides insight into the broader question of how plants generate and regulate their complex chemical arsenals. This knowledge not only enhances our understanding of plant biology but also has the potential to inform the development of new agricultural strategies for crop protection and improvement.

AgricultureGeneticsPlant Science

References

Main Study

1) Tomato root specialized metabolites evolved through gene duplication and regulatory divergence within a biosynthetic gene cluster.

Published 26th April, 2024

https://doi.org/10.1126/sciadv.adn3991

Related Studies

2) Genetics and biochemistry of secondary metabolites in plants: an evolutionary perspective.

Journal: Trends in plant science, Issue: Vol 5, Issue 10, Oct 2000

3) Convergent evolution of a metabolic switch between aphid and caterpillar resistance in cereals.

https://doi.org/10.1126/sciadv.aat6797

4) The formation and function of plant volatiles: perfumes for pollinator attraction and defense.

Journal: Current opinion in plant biology, Issue: Vol 5, Issue 3, Jun 2002


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