A Cold-Shock Protein from the South Pole-Dwelling Soil Bacterium sp. Confers Cold Tolerance to Rice.

Low temperature is a critical environmental factor restricting the physiology of organisms across kingdoms. In prokaryotes, cold shock induces the expression of various genes and proteins involved in cellular processes. Here, a cold-shock protein (ArCspA) from the South Pole-dwelling soil bacterium sp. A2-5 was introduced into rice, a monocot model plant species. Four-week-old transgenic rice plants grown in a cold chamber at 4 °C survived for 6 days. Cold stress significantly decreased the chlorophyll content in WT plants after 4 days compared with that in transgenic plants. RNA-seq analysis was performed on WT and transgenic rice with/without cold stress. GO terms such as "response to stress (GO:0006950)", "response to cold (GO:0009409)", and "response to heat (GO:0009408)" were significantly enriched among the upregulated genes in the transgenic rice under normal conditions, even without cold-stress treatment. The expression of five cold stress-related genes, (Os11g0454200), (Os11g0454300), (Os01g0702500), (Os01 g0859300), and (Os03g0285800), was significantly upregulated in the transgenic rice compared with the WT rice. These results indicate that the gene might be involved in the induction of cold-responsive genes and provide cold tolerance.