A low copy number, copia-like transposon in maize

Area of Science:

• Genetics
• Molecular Biology
• Plant Science

Background:

• Transposable elements (TEs) are mobile genetic sequences that can alter gene function and genome structure.
• Barley stripe mosaic virus (BSMV) infection has been linked to genetic instability and transposon activity in maize.
• The maize Adh1 gene is a well-studied locus for investigating genetic rearrangements.

Purpose of the Study:

• To characterize the Bs1 transposable element found in the maize Adh1 gene.
• To investigate the relationship between Bs1, barley stripe mosaic virus infection, and other transposable elements in maize.
• To understand the potential role of viral infection in mobilizing transposons.

Main Methods:

• Southern blot hybridization to detect Bs1 presence and copy number in maize and teosinte.
• Sequence analysis to determine the structural features of Bs1 and its flanking regions.
• Comparison of Bs1 sequences with known transposable elements and viral genomes.

Main Results:

• Bs1 is present in 1-5 copies across all tested maize and teosinte lines.
• Bs1 sequences do not hybridize with barley stripe mosaic virus.
• Bs1 exhibits structural similarities to Ty1, copia, and vertebrate pro-retroviruses, with 304-bp perfect direct repeats, distinguishing it from other plant transposons.
• No free terminal sequences or large internal deletions of Bs elements were detected.
• Bs1 appears unrelated to transposons that mobilized into the Shrunken gene following BSMV infection.

Conclusions:

• Bs1 is a distinct type of plant transposable element with unique structural features.
• Barley stripe mosaic virus infection may induce a 'genome shock' response, leading to the mobilization of various transposable elements in maize.
• The findings suggest a generalized increase in transposon activity in response to environmental stress induced by viral infection.