The development of the highly regenerable seed line Jemalong 2HA for transformation of Medicago truncatula-implications for regenerability via somatic embryogenesis

摘要

Regenerated Medicago truncatula cv. Jemalong plants showed very large increases in somatic embryogenesis. These large increases in somatic embryogenesis were inherited with progeny segregating into classes the authors categorised as high, moderate and low regenerators. The low regenerators had a similar frequency of somatic embryogenesis to Jemalong. Continued selection from the high regenerators allowed the development of the highly regenerable seed line Jemalong 2HA in which the progeny were allhigh regenerators. Jemalong 2HA is isogenic with Jemalong except for the enhanced somatic embryogenesis in Jemalong 2HA. It is suggested that a cycle of tissue culture resulting in an increase in somatic embryogenesis, may be a tool that can increase somatic embryogenesis in some recalcitrant species. Jemalong 2HA can be described as a super-embryogenic mutant and is valuable not only for its ease of transformation but also can provide insights into the nature of totipotency.