TRA1: A Locus Responsible for Controlling Agrobacterium-Mediated Transformability in Barley

Area of Science:

• Plant Biotechnology
• Genetics

Background:

• Agrobacterium-mediated transformation efficiency in barley (Hordeum vulgare L.) is genotype-dependent, with limited cultivars amenable to the process.
• Golden Promise is a widely used barley cultivar for transformation, utilizing developing embryos as donor tissue.

Purpose of the Study:

• To investigate if barley mutants with enlarged embryos exhibit altered transformation efficiencies.
• To identify the genetic locus responsible for enhanced transformation efficiency in mutant M1460.

Main Methods:

• Crossed mutant M1460 (high transformation efficiency) with recalcitrant cultivar Optic.
• Generated a segregating population through four rounds of backcrossing.
• Genotyped progeny and tested for Agrobacterium-mediated transformation efficiency.

Main Results:

• Mutant M1460, with a mutation at the LYS3 locus, showed transformation efficiency comparable to Golden Promise.
• Other lys3 mutants did not show enhanced transformation, indicating LYS3 is not the transformation locus.
• A specific region on chromosome 2H from M1460 was present only in transformable progeny.
• Identified TRA1 as a locus unique to M1460, likely located on chromosome 2H.

Conclusions:

• The transformation efficiency locus, TRA1, is distinct from LYS3 and unique to the M1460 mutant.
• A region on barley chromosome 2H contains the TRA1 locus, which controls Agrobacterium-mediated transformation.
• Further research is needed to pinpoint the specific gene(s) within the 225 genes in the identified 2H region responsible for TRA1.