Evolutionary Dynamics of Transposable Elements Following a Shared Polyploidization Event in the Tribe Andropogoneae

Area of Science:

• Plant genomics
• Evolutionary biology
• Molecular genetics

Background:

• Polyploidization and transposable element (TE) activity are key drivers of plant genome evolution.
• The Zea-Tripsacum clade provides a model to study TE dynamics post-polyploidization.

Purpose of the Study:

• Investigate TE activity and accumulation in the Zea-Tripsacum clade following a shared polyploidization event.
• Compare TE evolutionary dynamics across Zea, Tripsacum, and related diploid species.

Main Methods:

• Comparative genomics of TE content and composition.
• Analysis of LTR-retrotransposon superfamily expansion (copia).
• Genomic distribution analysis of TE insertions near genes.

Main Results:

• Significant variation in repeat content observed across Zea, Tripsacum, Urelytrum digitatum, and Sorghum bicolor.
• Expansion of the copia superfamily in Zea mays and Tripsacum dactyloides, adapted to temperate environments.
• Biased insertion of copia elements near genes involved in plant development, defense, and abiotic stress response, particularly in Zea and Tripsacum.

Conclusions:

• TE insertions, specifically copia, are enriched near abiotic stress-response genes in Zea and T. dactyloides, indicating independent evolution post-divergence.
• Duplicate gene copies in polyploids may provide neutral insertion sites for TEs, facilitating subfunctionalization via insertional mutagenesis.