UV sterilization can solve the safety concern of lettuce that has been repeatedly recalled due to deadly Escherichia Coli and/or Listeria monocytogenes contamination. However, the strong UV radiation could damage lettuce development and induce senescence. It is also known that climate change will negatively impact lettuce growth and development by inducing, for example, senescence, and breeding lettuce resilient to climate change is much needed. This research project aims to address these grand challenges by using the CRISPR/CAS9 genome-editing tool. Briefly, a senescence-master regulator has been found to mediate all adverse environment (including UV radiation)-induced senescence, and knocking out the gene will render the new lettuce germplasm resistant to UV sterilization and many other adverse environmental conditions. Toward the goals, this project has used the related binary vector for knocking out the master regulator gene in lettuce and has transferred the binary vector into lettuce leaf tissues and cotyledons via agrobacterium-mediated transformation. The edited lettuce lines will most likely be resistant to strong UV sterilization (thus safer lettuce) and changing climate.