Novel, developmentally specific control of Ds transposition in maize

Area of Science:

• Plant genetics
• Molecular biology
• Developmental biology

Background:

• Plants often transmit somatic mutations to progeny due to late gamete formation.
• Ac/Ds transposon activity in maize provides classic examples of somatic and germinal reversion correlations.

Purpose of the Study:

• To investigate a maize Ds allele (wx-m5:CS7) where somatic and germinal reversion frequencies diverge.
• To understand the mechanism behind suppressed germinal reversion in specific maize mutants.

Main Methods:

• Characterization of the wx-m5:CS7 Ds allele in maize.
• Comparison of somatic and germinal reversion frequencies with a second Ds allele (wx-m5:CS8).
• Analysis of Ds excision in somatic tissues and gamete formation.

Main Results:

• wx-m5:CS7 exhibits a 100-fold suppression of revertant gamete formation compared to wx-m5:CS8, despite similar somatic reversion.
• Ds excision in somatic tissues is not significantly reduced in wx-m5:CS7.
• Suppressed germinal reversion is heritable and linked to a dominant, trans-acting mutation near the Wx locus.

Conclusions:

• A novel mechanism of developmental control over Ac/Ds elements exists in maize.
• A dominant mutation suppresses transposon excision specifically in the germline (shoot meristem), decoupling it from somatic events.