Cisgenic barley with improved phytase activity.

Area of Science:

• Agricultural biotechnology
• Plant molecular biology
• Genetics

Background:

• Cisgenesis involves using a plant's own genes or those from sexually compatible relatives.
• Eliminating foreign DNA, like selection genes, is crucial for cisgenic development.
• Barley phytase (HvPAPhy_a) is a target gene for enhancing grain nutritional value.

Purpose of the Study:

• To evaluate the feasibility of cisgenesis in barley using the HvPAPhy_a gene.
• To develop marker-free cisgenic barley lines.
• To confirm the absence of vector backbone sequences in putative cisgenic plants.

Main Methods:

• Agrobacterium-mediated transformation of barley with a construct containing HvPAPhy_a and a selection gene.
• Marker gene elimination strategy to remove the selection gene.
• Analysis of T(0) and T(1) generations for gene integration, expression, and segregation.
• Southern blot analysis to confirm the absence of vector backbone sequences.

Main Results:

• 11 potentially cisgenic T(1) lines were identified from 72 T(0) lines.
• Selected cisgenic lines showed 2.6- and 2.8-fold increases in grain phytase activity.
• Phytase activity remained stable over three generations.
• Absence of vector backbone sequences confirmed in flanking regions of the integrated gene.

Conclusions:

• Cisgenic barley can be generated with reasonable efficiency using current methods.
• The developed lines meet the criteria for cisgenesis, including the absence of foreign DNA.
• This study demonstrates a viable approach for producing cisgenic crops with enhanced traits.