Medical Faculty, Kunming University of Science and Technology, Kunming, 650500, Yunnan, China.
Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, 650500, Yunnan, China.
Curr Microbiol. 2022 Jul 14;79(9):253. doi: 10.1007/s00284-022-02957-8.
The aim of this study was to investigate the role of RKHog1 in the cold adaptation of Rhodosporidium kratochvilovae strain YM25235 and elucidate the correlation of biosynthesis of polyunsaturated fatty acids (PUFAs) and glycerol with its cold adaptation. The YM25235 strain was subjected to salt, osmotic, and cold stress tolerance analyses. mRNA levels of RKhog1, Δ-fatty acid desaturase gene (RKD12), RKMsn4, HisK2301, and RKGPD1 in YM25235 were detected by reverse transcription quantitative real-time PCR. The contents of PUFAs, such as linoleic acid (LA) and linolenic acid (ALA) was measured using a gas chromatography-mass spectrometer, followed by determination of the growth rate of YM25235 and its glycerol content at low temperature. The RKHog1 overexpression, knockout, and remediation strains were constructed. Stress resistance analysis showed that overexpression of RKHog1 gene increased the biosynthesis of glycerol and enhanced the tolerance of YM25235 to cold, salt, and osmotic stresses, respectively. Inversely, the knockout of RKHog1 gene decreased the biosynthesis of glycerol and inhibited the tolerance of YM25235 to different stresses. Fatty acid analysis showed that the overexpression of RKHog1 gene in YM25235 significantly increased the content of LA and ALA, but RKHog1 gene knockout YM25235 strain had decreased content of LA and ALA. In addition, the mRNA expression level of RKD12, RKMsn4, RKHisK2301, and RKGPD1 showed an increase at 15 °C after RKHog1 gene overexpression but were unchanged at 30 °C. RKHog1 could regulate the growth adaptability and PUFA content of YM25235 at low temperature and this could be helpful for the cold adaptation of YM25235.
本研究旨在探讨 RKHog1 在 Rhodosporidium kratochvilovae 菌株 YM25235 冷适应中的作用，并阐明多不饱和脂肪酸（PUFA）和甘油生物合成与其冷适应的相关性。对 YM25235 菌株进行盐、渗透和冷应激耐受分析。通过反转录定量实时 PCR 检测 RKhog1、Δ-脂肪酸去饱和酶基因（RKD12）、RKMsn4、HisK2301 和 RKGPD1 的 mRNA 水平。使用气相色谱-质谱法测量 PUFA（如亚油酸（LA）和亚麻酸（ALA））的含量，然后测定 YM25235 的生长速度及其在低温下的甘油含量。构建了 RKHog1 过表达、敲除和修复菌株。应激抗性分析表明，RKHog1 基因的过表达增加了甘油的生物合成，并分别增强了 YM25235 对冷、盐和渗透胁迫的耐受性。相反，RKHog1 基因的敲除降低了甘油的生物合成，并抑制了 YM25235 对不同胁迫的耐受性。脂肪酸分析表明，RKHog1 基因在 YM25235 中的过表达显著增加了 LA 和 ALA 的含量，但 RKHog1 基因敲除 YM25235 菌株的 LA 和 ALA 含量降低。此外，RKHog1 基因过表达后，RKD12、RKMsn4、RKHisK2301 和 RKGPD1 的 mRNA 表达水平在 15°C 时升高，但在 30°C 时不变。RKHog1 可以调节 YM25235 在低温下的生长适应性和 PUFA 含量，这有助于 YM25235 的冷适应。
