In this module, we will take a close look at Xanthomonas bacteria and more specifically the Tal effectors it secretes. Tal effectors are eukaryotic transcription factors that this particular bacteria, and others similar to it, secrete into plants attacking their genome to look for specific base pairings to upregulate that sequence benefiting the bacteria. Tal effectors are made up of a repeat of about 30 amino acids which 2 amino acids correspond to a specific base pair in the plant DNA changing the genome while acting as a transcription factor allowing for more secretion of copper or glucose that the bacteria will need. These Tal effectors are the subject of many research projects looking into making engineered/artificial Tal effectors to up or down regulate specific genes in human cells. Look at the picture to the right. You have most likely seen this on trees outside your house; this is what it looks like when bacteria, like the Xanthomonas, infect a plant with these TAL effectors.
If you would like to read more about current research being done on Tal effectors and how they will become useful in people's lives, please check out the refrences listed below.
Go to the next slide to see a Tal effector in action.