Bacteria that inhabit glaciers usually produce carotenoids. Here, we report that a group of zeaxanthin-producing glacial Flavobacterium exhibited light-promoted growth. Of the tested 47 strains, 45 showed increased growths but two died under illumination at 50 μmol photon m⁻² s⁻¹. Light stimulation occurred mainly in either anoxic or nutrient-poor cultures, while the same levels of light promotion were found for that grown at 14 and 7 °C. Pigment assays identified overrepresentative zeaxanthin but trace retinal in the light promoted 45 strains, while flexirubin was exclusively in the light-lethal two. Genomic analysis revealed the gene cluster for zeaxanthin synthesis in the 45 strains, in which 37 strains also harbored the proteorhodopsin gene prd. Transcriptomic analysis found that light-induced expressions of both the zeaxanthin synthesis and proteorhodopsin genes. Whereas, deletion of the prd gene in one strain did not diminish light promotion, inhibition of zeaxanthin synthesis did. In comparison, no light promotion was determined in a glacier Cryobacterium luteum that produced a non-zeaxanthin-type carotenoid. Therefore, light stimulation on the glacial Flavobacterium is mostly likely related to zeaxanthin, which could provide better photoprotection and sustain membrane integrity for the organisms living in cold environments.

栖息在冰川中的细菌通常会产生类胡萝卜素。在这里，我们报告了一组产生玉米黄质的冰川黄杆菌表现出光促进的生长。在测试的 47 株菌株中，45 株表现出增加的生长，但 2 株在 50 μmol 光子 m ^-2  s ^-1的光照下死亡。光刺激主要发生在缺氧或营养贫乏的培养物中，而在 14 和 7°C 生长的培养物中发现了相同水平的光促进。色素测定鉴定出代表性过高的玉米黄质，但在光下微量视黄醛促进了 45 株，而柔红霉素仅在光致死的两种中。基因组分析揭示了 45 株玉米黄质合成基因簇，其中 37 株还含有原视紫红质基因珠三角_ 转录组学分析发现，光诱导玉米黄质合成和蛋白视紫红质基因的表达。然而，一种菌株中prd基因的缺失并没有减少光的促进作用，但玉米黄质合成的抑制作用却没有。相比之下，在产生非玉米黄质类胡萝卜素的冰川黄冻杆菌中没有确定光促进作用。因此，对冰川黄杆菌的光刺激很可能与玉米黄质有关，玉米黄质可以为生活在寒冷环境中的生物提供更好的光保护和维持膜的完整性。