Transcriptome sequencing analysis of maize embryonic callus during early redifferentiation

Area of Science:

• Plant Molecular Biology
• Genetics
• Biotechnology

Background:

• Maize genetic manipulation is vital for improving crop traits like stress resistance and yield.
• Genotypic differences in maize embryonic callus (EC) induction and regeneration capacity create challenges for genetic transformation.
• Understanding the molecular basis of EC regeneration is crucial for efficient maize breeding.

Purpose of the Study:

• To investigate the molecular differences underlying early redifferentiation stages in maize embryonic calli from genotypes with varying regeneration capacities.
• To identify differentially expressed genes (DEGs) and key pathways associated with high and low regeneration potential in maize EC.
• To elucidate the role of specific genes, such as WOX genes, in promoting maize EC regeneration.

Main Methods:

• Transcriptome sequencing analysis of maize embryonic calli from four inbred lines (two high-regeneration, two low-regeneration) at three early redifferentiation stages (1-9 days).
• Comparative analysis of differentially expressed genes (DEGs) between high- and low-regeneration lines and their controls.
• Bioinformatic analysis to identify enriched pathways and gene functions associated with regeneration capacity.

Main Results:

• A significant number of DEGs (1694-7193) were identified across the four maize inbred lines during early redifferentiation.
• High-regeneration lines (141, DH40) showed specific upregulation of genes related to photosynthesis, chlorophyll metabolism, and hormone signaling.
• Low-regeneration lines (ZYDH381-1, DH3732) exhibited specific DEGs involved in nitrogen metabolism, starch/sucrose metabolism, and circadian rhythm.
• WOX genes, important for embryo development, were specifically upregulated in high-regeneration maize lines, suggesting a role in promoting callus regeneration.

Conclusions:

• Early redifferentiation stages (1-3 days) are critical for maize EC regeneration.
• Distinct molecular pathways are associated with high and low regeneration capacities in maize embryonic calli.
• Upregulation of WOX genes in high-regeneration lines offers potential targets for improving maize genetic transformation efficiency.