Stresses make microbe undergo programmed cell death: Mechanisms and opportunities.

In recent years, programmed cell death (PCD) has attracted the attention of many scholars as an active death process. PCD refers to an active extinction process that occurs after cells receive a certain signal or are stimulated by certain factors in order to maintain the stability of the internal environment. It is orchestrated by precise molecular circuitry. Initially, PCD was thought to exhibit altruistic behavior of "active devotion", a physiological characteristic of multicellular organisms. However, many evidences show that PCD also exists in microbe, and researchers in recent years have found that some stressors during modern food processing could cause microbe undergo different forms of programmed death, including ultraviolet, gamma radiation, cold plasma, ultrasound, weak carboxylic acids and H2O2. The attention to these situations will help researchers to explore novel mechanisms of sterilization. At present, microbial PCD can be further divided into three types, including apoptosis-like death, autolytic death, and toxin-antitoxin systems based on the differences in their intrinsic mechanisms. In order to better utilize these PCD mechanisms, four directions are provided from searching for new antimicrobial targets, development of new types of preservatives, engineering design in the field of synthetic biology and modification of fermentation strains. We believe that this review can provide useful help for scholars to carry out further research on microbial PCD.