Maize chromatin introgression's effect in oat × maize addition lines.

Area of Science:

• Genetics
• Plant breeding
• Cytology

Background:

• Oat (Avena sativa L.) × maize (Zea mays L.) addition lines are valuable for studying gene expression, chromatin structure, and trait introgression.
• Understanding maize chromatin integration into the oat genome is crucial for developing novel intergeneric hybrids.

Purpose of the Study:

• To comprehensively analyze oat × maize addition lines to understand maize chromatin introgression into the oat genome.
• To investigate the effects of maize chromatin on oat cell cycle dynamics, chromosome behavior, and agronomic traits.

Main Methods:

• Polymerase chain reaction (PCR) using the maize retrotransposon Grande-1 to confirm maize chromatin presence.
• Genomic in situ hybridization (GISH) to visualize maize chromosome segments in oat.
• Analysis of cell cycle dynamics, DNA replication, mitotic abnormalities (micronuclei, anaphase bridges), and morphological/physiological traits.

Main Results:

• Maize chromatin was confirmed in three oat addition lines.
• Maize chromosome presence disturbed oat's typical centromere-telomere polarization, with chromatin near the nuclear periphery.
• Introgression prolonged DNA replication, altered cell cycle, and induced mitotic abnormalities.
• Addition lines exhibited smaller seeds, hampered seedling growth, and reduced yield parameters.

Conclusions:

• Maize chromatin introgression significantly impacts oat genome stability and cell biology.
• Observed morphological and yield reductions question the immediate utility of these specific oat × maize hybrids.
• Further research is needed to assess the long-term stability and potential applications of intergeneric hybrids involving oat and maize.