[Campbell Biology P.709] The text describes that sym genes, essential for mycorrhizae format... | Practice Question

The text describes that sym genes, essential for mycorrhizae formation, were found in major plant lineages, including basal liverworts, and that transferring a liverwort sym gene to a flowering plant mutant restored its ability to form mycorrhizae. What is the most significant evolutionary implication of these findings?

  • A: Mycorrhizal associations are a recent evolutionary development unique to flowering plants.
  • B: Liverworts are more advanced than flowering plants in their genetic mechanisms for symbiosis.
  • C: The *sym* genes and their function in mycorrhizal formation have been highly conserved across diverse plant lineages for hundreds of millions of years, highlighting the ancient importance of these symbiotic relationships.
  • D: Fungi can directly transfer genetic material to plants to facilitate symbiotic relationships.

Explanation

The presence of sym genes in basal plant lineages like liverworts and their ability to function in more derived flowering plants indicates that these genes and their role in mycorrhizal symbiosis are ancient and have been evolutionarily conserved over vast periods.