Genomic stability and long-term transgene expression in poplar

Area of Science:

• Plant Biotechnology
• Forest Genetics
• Molecular Biology

Background:

• Stable foreign gene expression is crucial for long-lived transgenic plants like trees.
• Limited data exists on long-term transgene expression and genomic stability in transgenic forest trees.
• Initial screenings focus on T-DNA integration and expression, often overlooking long-term stability.

Purpose of the Study:

• To investigate genome-wide changes post-T-DNA integration in hybrid aspen.
• To assess the long-term stability of transgene expression in aged transgenic hybrid aspen lines.
• To evaluate the durability of foreign gene expression over the lifespan of forest trees.

Main Methods:

• AFLP analysis was used to detect genome-wide changes in four independent rolC-transgenic hybrid aspen lines compared to controls.
• PCR was employed to confirm the presence of the rolC gene in various transgenic lines.
• Phenotypic analysis and Northern blot experiments were conducted to demonstrate rolC transgene expression in long-term cultures and glasshouse-grown trees.

Main Results:

• AFLP studies revealed only minor genome-wide changes following T-DNA integration.
• The rolC gene was successfully detected in all examined transgenic lines via PCR.
• Both 19-year-old in vitro cultures and up to 18-year-old glasshouse-grown trees exhibited stable rolC transgene expression.

Conclusions:

• T-DNA integration in hybrid aspen leads to minimal genomic alterations.
• Transgenic hybrid aspen demonstrates robust and stable foreign gene expression over extended periods (up to 19 years).
• These findings support the feasibility of long-term genetic stability and expression in transgenic forest trees.