Polyploidization as a retraction force in plant genome evolution: sequence rearrangements in triticale

Area of Science:

• Plant genetics and evolution
• Genomics and molecular biology
• Crop science

Background:

• Polyploidization is a key evolutionary driver in plants, inducing genomic stress and modifications.
• Understanding DNA sequence restructuring and involved elements during polyploidization remains limited.

Purpose of the Study:

• To investigate polyploidization-induced genetic restructuring in triticale using molecular markers.
• To characterize the specific DNA sequences involved in these genomic rearrangements.

Main Methods:

• Utilized PCR-based molecular markers: Inter Retrotransposons Amplified Polymorphism (IRAP), Retrotransposons Microsatellite Amplified Polymorphism (REMAP), and Inter Simple Sequence Repeat (ISSR).
• Performed comparative analysis of banding profiles between parental species (wheat, rye) and triticale.
• Conducted sequence analysis of rearranged genomic fragments and Fluorescent In Situ Hybridization (FISH).

Main Results:

• Confirmed absence of intraspecific variation in wheat, rye, and triticale using IRAP, REMAP, and ISSR.
• Identified 34% monomorphic bands between wheat and rye; triticale showed 51% rearranged bands, primarily due to rye band loss (83%).
• Sequence analysis revealed retrotransposon-related elements (copia-like), hydroxyproline-rich glycoproteins (HRGP), and microsatellite sequences involved in rearrangements. FISH indicated preferential distribution on rye chromosomes.

Conclusions:

• Polyploidization in triticale induces significant genetic restructuring, involving retrotransposons, coding sequences, and microsatellites.
• Identified specific genomic regions (hotspots) prone to rearrangements, potentially influenced by chromatin condensation.
• Provides insights into the molecular mechanisms underlying genome evolution during polyploidization.