R. raciborskii is known for growing under wide ranges of temperature and light. In temperate regions, however, low temperature and high light may serve as a stressful condition for invading tropical populations. The genetic basis of R. raciborskii's adaptation to this combination of stresses are unknown. In this study, the growth rate and the expression of genes that may be crucial in the response to the chill/light stress of two R. raciborskii strains (differing in their climatic origin and toxicity) exposed to low temperature and high light were examined. Results showed that AMU-DH-30, a non CYN (cylindrospermopsin) producing strain isolated from the temperate region, exhibited under stress the upregulation of genes involved in the protein translation (rbp1, nusG, hflX), membrane fluidity (desA), photosynthetic activity (ccr2 and ftsH), and the accumulation of compatible solutes (asd). In contrast, a CYN producing Australian strain CS-505 was not able to adapt quickly and to continue growth during stress conditions. Intriguingly, CS-505 and AMU-DH-30 had a similar ability to resume growth when the stress conditions subsided. Moreover, in strain CS-505 the cyrB gene was significantly upregulated under the stress conditions. The presented results shed new light on the possible mechanisms involved in the response of R. raciborskii to chill/light stress.

中文翻译：

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波兰和澳大利亚 Raphidiopsis raciborskii 菌株对寒冷/光照胁迫的不同基因表达反应

R. raciborskii 以在广泛的温度和光照范围内生长而闻名。然而，在温带地区，低温和强光可能成为入侵热带种群的压力条件。R. raciborskii 适应这种压力组合的遗传基础尚不清楚。在这项研究中，检测了暴露于低温和强光下的两种 R. raciborskii 菌株（其气候起源和毒性不同）的生长速率和基因表达，这些基因可能对响应寒冷/光胁迫起关键作用。结果表明，AMU-DH-30 是一种从温带地区分离出来的不产生 CYN（圆柱胚素）的菌株，在压力下表现出参与蛋白质翻译（rbp1、nusG、hflX）、膜流动性（desA）、光合作用的基因的上调。活动（ccr2 和 ftsH），以及相容溶质 (asd) 的积累。相比之下，产生 CYN 的澳大利亚菌株 CS-505 无法快速适应并在压力条件下继续生长。有趣的是，当压力条件消退时，CS-505 和 AMU-DH-30 具有相似的恢复生长能力。此外，在菌株 CS-505 中，cyrB 基因在胁迫条件下显着上调。所呈现的结果揭示了 R. raciborskii 对寒冷/光照应激反应的可能机制。在菌株 CS-505 中，cyrB 基因在胁迫条件下显着上调。所呈现的结果揭示了 R. raciborskii 对寒冷/光照应激反应的可能机制。在菌株 CS-505 中，cyrB 基因在胁迫条件下显着上调。所呈现的结果揭示了 R. raciborskii 对寒冷/光照应激反应的可能机制。