When genomes collide: aberrant seed development following maize interploidy crosses

Area of Science:

• Plant reproductive biology
• Genomics and genetics
• Developmental biology

Background:

• Wide- or interploidy crosses in angiosperms often result in unpredictable outcomes, including seed abortion.
• Reciprocal interploidy crosses in maize have been studied to understand alterations in endosperm tissue domains and gene expression.

Purpose of the Study:

• To investigate the consequences of reciprocal interploidy crosses in maize on endosperm development.
• To analyze changes in endosperm-specific gene expression following interploidy crosses.

Main Methods:

• Reciprocal crosses between diploid and tetraploid maize lines.
• Utilized GUS reporter lines to study endosperm domain development.
• Employed semi-quantitative RT-PCR to analyze gene expression in developing endosperms.

Main Results:

• Interploidy crosses yielded small, infertile seeds with defective endosperms.
• Maternal excess seeds were smaller, cellularized earlier, and accumulated more starch than paternal excess seeds.
• Endosperms from reciprocal crosses showed disrupted functional domains, altered cell proliferation, and differential gene expression based on cross direction.

Conclusions:

• Interploidy crosses disrupt the balance between cell proliferation and differentiation in the maize endosperm.
• Unbalanced crosses affect transfer cell differentiation and deregulate the temporal program of endosperm development.