Those are good methods of sterilization, but there are also various peroxides that might work without killing plant tissue.

The plants were air dried for 48 h before being thoroughly washed to remove all soil from the root mass. Washing included a sonication step to dislodge any soil and organic matter from the roots. The roots were excised and subjected to a three-step surface sterilization procedure: a 60-s wash in 99% ethanol, followed by a 6-min wash in 3.125% NaOCl, a 30-s wash in 99% ethanol, and a final rinse in sterile reverse osmosis-treated (RO) water. The surface-sterilized roots were then aseptically sectioned into 1-cm fragments and distributed onto the isolation media, followed by incubation at 27°C for up to 4 weeks. Several isolation media were developed for the isolation of endophytic actinobacteria and used throughout the experiment.