Proliferating cell nuclear antigen involves in temperature stress tolerance of Ulva prolifera

Ulva prolifera is the dominant species of "green tide", and has higher tolerance to environmental stresses such as temperature. However, the molecular mechanisms are still unclear. Here, transcriptome analysis, Western blot and RT-qPCR analysis of U. prolifera suggested that, under temperature stresses (4{degrees}C, 36{degrees}C), the expression of PCNA and CyclinA was promoted, and the MAPK signaling was activated. Besides, the results showed that PCNA interacted with CyclinA. Interestingly, the expression of miR-2916, which was predicted to bind PCNA at -552[~]-772, was negatively correlated with the expression of PCNA under temperature stresses (4{degrees}C, 36{degrees}C). In addition, the results showed that low temperature (4{degrees}C) had no obvious effect on the survival, the formation of cell walls, and the division of protoplasts. However, high temperature (36{degrees}C) had obvious effect on them. PCNA inhibitors increased the sensitivity of the protoplasts under temperature stresses. Together, our results suggested PCNA regulating the proliferation in response to the temperature stress of U. prolifera was associated with miR-2916/PCNA/CyclinA/MAPK pathway. In conclusion, the study preliminarily illuminates the molecular mechanism in response to temperature stress of U. prolifera, and may provide a new insight for prevention of green tide.