Improved Disease Resistance on the Way – One Key to Soybean Improvement

As spring planting season begins, it is difficult to predict those diseases that may be most problematic during the growing season of 2008. So much depends upon rainfall, temperature and a myriad of other factors that can affect crops and pathogens. This includes potential for resistance to various pathogens. Despite all the management practices we talk about, disease resistance remains one of the most practical and economic ways to control plant disease. But, sometimes the genes that confer that resistance are not so easy to find. Iowa State University scientists, in research that would not have been possible without support by soybean check-off dollars, have recently been working to develop a means to find and characterize resistance genes to pathogens when resistance has been difficult to find

Identifying Factors that Determine Effectiveness of Delivery Agents in Biolistic Delivery Using a Library of Amine-Containing Molecules

Biolistic transfection is a popular and versatile tool for plant transformation. A key step in the biolistic process is the binding of DNA to the heavy microprojectile using a delivery agent, usually a positively charged molecule containing amine groups. Currently, the choice of the commercial delivery agent is mostly limited to spermidine. In addition, the detailed delivery mechanism has not been reported. To help broaden the selection of the delivery agent and reveal the fundamental mechanisms that lead to high delivery performance, a library of amine-containing molecules was investigated. A double-barrel biolistic delivery device was utilized for testing hundreds of samples with much-improved consistency. The performance was evaluated on onion epidermis. The binding and release of DNA were measured via direct high-performance liquid chromatography analysis. This study shows that the overwhelming majority of the amine library performed at the same level as spermidine. To further interpret these results, correlations were performed with thousands of molecular descriptors generated by chemical modeling. It was discovered that the overall charge is most likely the key factor to a successful binding and delivery. Furthermore, even after increasing the amount of the DNA concentration 50-fold to stress the binding capacity of the molecules, the amines in the library continued to deliver at a near identical level while binding all the DNA. The increased DNA was also demonstrated with a Cas9 editing test that required a large amount of DNA to be delivered, and the result was consistent with the previously determined amine performance. This study greatly expands the delivery agent selection for biolistic delivery, allowing alternatives to a commercial reagent that are more shelf-stable and cheaper. The library also offers an approach to investigate more challenging delivery of protein and CRISPR-Cas via the biolistic process in the future.This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in ACS Applied Bio Materials, copyright © 2022 American Chemical Society after peer review. To access the final edited and published work see DOI: 10.1021/acsabm.2c00689. Posted with permission