Source: The Plant Journal
Volume 45 Page 847  - March 2006
doi:10.1111/j.1365-313X.2005.02636.x
Volume 45 Issue 5

A high-throughput screen for genes from castor that boost hydroxy fatty acid accumulation in seed oils of transgenic Arabidopsis
by Chaofu Lu, Martin Fulda, James G. Wallis and John Browse

SUMMARY

It is desirable to produce high homogeneity of novel fatty acids in oilseeds through genetic engineering to meet the increasing demands of the oleo-chemical industry. However, expression of key enzymes for biosynthesis of industrial fatty acids usually results in low levels of desired fatty acids in transgenic oilseeds. The abundance of derivatized fatty acids in their natural species suggests that additional genes are needed for high production in transgenic plants. We used the model oilseed plant Arabidopsis thaliana expressing a castor fatty acid hydroxylase (FAH12) to identify genes that can boost hydroxy fatty acid accumulation in transgenic seeds. Here we describe a high-throughput approach that, in principle, can allow testing of the entire transcriptome of developing castor seed endosperm by shotgun transforming a full-length cDNA library into an FAH12-expressing Arabidopsis line. The resulting transgenic seeds were screened by high-throughput gas chromatography. We obtained several lines transformed with castor cDNAs that contained increased amounts of hydroxy fatty acids in transgenic Arabidopsis. These cDNAs were then isolated by PCR and retransformed into the FAH12-expressing line, thus confirming their beneficial contributions to hydroxy fatty acid accumulation in transgenic Arabidopsis seeds. Although we describe an approach that is targeted to oilseed engineering, the methods we developed can be applied in many areas of plant biotechnology and functional genomic research.

Source: http://www.blackwell-synergy.com/doi/abs/10.1111/j.1365-313X.2005.02636.x

Novel approach to fatten up castor beans

A team of researchers of the Institute of Biological Chemistry, Washington State University, U.S. describe a high throughput approach designed to identify genes important for oil yield in castor bean. Their article: “A high-throughput screen for genes from castor that boost hydroxy fatty acid accumulation in seed oils of transgenic Arabidopsis” is published in the latest issue of the Plant Journal.

The over-expression of known enzymes in the biosynthetic pathway of fatty acids in castor beans has not been a successful approach to develop biotech castor beans with increased oil content, suggesting that additional genes to the ones engineered are required. To identify novel genes, the authors used the model species Arabidopsis thaliana and generated an Arabidopsis line over-expressing the castor fatty acid hydroxylase FAH12 gene. They subsequently introduced into this line the entire set of cDNAs expressed in the castor seed endosperm (the nutritive tissue surrounding the embryo within seeds) by biolistic transformation. The resulting transgenic seeds were screened to isolate lines with increased oil yields. The cDNAs responsible were then identified by PCR, and retransformed into castor seeds to confirm their contribution. Although this approach was designed for oilseed engineering, it can be applied to many areas of plant biotechnology.

To view the abstract of the article “A high-throughput screen for genes from castor that boost hydroxy fatty acid accumulation in seed oils of transgenic Arabidopsis” visit:
http://www.blackwell-synergy.com/doi/abs/10.1111/j.1365-313X.2005.02636.x