Submitted to: International Sorghum and Millets Newsletter
Publication Type: Popular Publication
Publication Acceptance Date: October 15, 2005
Publication Date: December 1, 2005
Citation: Huang, Y. 2005. Development of a new genetic transformation system for sorghum using Agrobacterium and immature inflorescences. International Sorghum and Millets Newsletter. 46:69-72. Technical Abstract: Genetic improvement of sorghum [Sorghum bicolor (L.) Moench] has depended on conventional plant breeding methods. As a result, sorghum insect management has mainly relied on the development of pest resistant varieties through traditional breeding and improved cultural management practices. In recent years, there has been increased pressure to sustain, and even enhance, crop productivity with less use of chemicals. Conventional breeding has made a great contribution to sorghum production in the past and will continue to be an important component of future sorghum improvement programs, but traditional breeding has some inherent limitations due to natural barriers (i.e., sexual incompatibility) and the narrow genetic variability (limited gene pool) that is available. Plant biotechnology is a promising tool for changing agriculture, potentially providing new solutions to age-old agricultural problems. In particular, significant advances in gene identification and gene transfer techniques have allowed the incorporation of beneficial genes for specific agronomic traits into diverse crop plants. Today these new tools enable plant breeders to design new varieties by inserting desired foreign genes, including insect resistance genes, into existing commercial lines in an extremely short period of time. During the last decade, many of the world’s most important crops (including wheat, maize, rice, soybean, and cotton) have already been engineered with increased resistance to insects and diseases. Although similar research has been attempted in sorghum, it has lagged behind that of other cereal crops. The limited progress in sorghum transformation is partly due to difficulties associated with its tissue culture and partly due to lack of efficient protocols for transformation. There have been only a few reports on sorghum transformation, and the majority of these transformation experiments were based on microprojectile bombardment devices for delivering foreign genes into the plant cells. As for the starter tissues, these transformation protocols have relied on use of mature or immature embryos. However, it has been suggested that Agrobacterium may be a better system for DNA delivery in higher plants, including graminaceous monocots. Thus, our current research has been directed towards the development of the Agrobacterium-mediated transformation system for sorghum. This paper reports the progress of the project on sorghum transformation using Agrobacterium and immature inflorescenes.