Provided herein are methods and systems for altering the genome of an organelle. In some embodiments, the method comprises introducing into an organelle a recombinant DNA construct comprising a first polynucleotide encoding at least one guide RNA and a second polynucleotide encoding a polynucleotide guided polypeptide; and growing a cell comprising the organelle under conditions in which the first polynucleotide and the second polynucleotide are each expressed.