Among the one trillion or so species that share space on our planet, complex relationships have emerged over time. Such relationships, in which two or more species closely interact, are collectively termed symbiosis. Although it’s commonly assumed that symbiotic relationships are mutually beneficial, this example constitutes only one type of symbiosis (known as mutualism). The traditional predator-prey relationship, clearly a one-sided arrangement, is also an example of symbiosis.
The sheer diversity of microbial species has led to the development of many well-characterized relationships with plants and animals. Perhaps the best-known example of mutualism in this context is the process of nitrogen fixation. In this process, various types of bacteria that live in water, soil or root nodules convert atmospheric nitrogen into forms that are readily used by plants. On the other hand, some types of bacteria-plant relationships are parasitic: the bacteria rely on the plant for survival but end up damaging their host. Parasitic relationships can have devastating ecological and economic consequences when they affect food crops.
Isolating DNA from plant tissues is difficult for many reasons. Unlike animal cells, plant cells have rigid cell walls, often made of tough fibrous material, and contain proteins and enzymes and other compounds such as polysaccharides and polyphenols that play a role in different cellular processes. These compounds can interfere with DNA isolation as well as downstream applications such as PCR. For these reasons, DNA isolation methods that are used successfully for other sample types may not work well to isolate DNA from plant material. Continue reading “DNA Purification from Plants: Not All Methods are Equal”
My one attempt at working with plant DNA when I was at the lab bench was trying to create a shotgun library from a rice BAC. Never have I needed to isolate nucleic acid from the source material, but based on my conversations with plant scientists, it can be problematic endeavor between the tough tissue and the compounds that can copurify during extraction and inhibit downstream applications. And if you want to isolate DNA or DNA from plant samples in an automated format, that just adds to the difficulties. Here I review an Applications in Plant Sciences article that compares DNA isolation using the Maxwell® 16 System with two other methods on 25 different plant species samples. The authors note that Promega provided the Maxwell® 16 instrument, DNA isolation cartridges and advice on its use. Continue reading “Extraction of Plant DNA Made Easy”