Abstract

Biological soil crusts (BSCs) are found in drylands, cover ∼12% of the Earth's surface in arid and semi-arid lands and their destruction is considered an important promoter of desertification. These crusts are formed by the adhesion of soil particles to polysaccharides excreted mostly by filamentous cyanobacteria, which are the pioneers and main primary producers in BSCs. Desert BSCs survive in one of the harshest environments on Earth, and are exposed to daily fluctuations of extreme conditions. The cyanobacteria inhabiting these habitats must precisely read the changing conditions and predict, for example, the forthcoming desiccation. Moreover, they evolved a comprehensive regulation of multiple adaptation strategies to enhance their stress tolerance. Here we focus on what distinguishes cyanobacteria able to revive after dehydration from those that cannot. While important progress has been made in our understanding of physiological, biochemical and omics aspects, clarification of the sensing, signal transduction and responses enabling desiccation tolerance are just emerging. We plot the trajectory of current research and open questions ranging from general strategies and regulatory adaptations in the hydration/desiccation cycle, to recent advances in our understanding of photosynthetic adaptation. The acquired knowledge provides new insights to mitigate desertification and improve plant productivity under drought conditions.

中文翻译：

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沙漠生物土壤结皮恶劣条件下的阅读与生存：蓝藻的观点

摘要

生物土壤结皮（BSCs）存在于旱地，在干旱和半干旱地区约占地球表面的 12%，它们的破坏被认为是荒漠化的重要促进因素。这些结皮是由土壤颗粒粘附到多糖上形成的，这些多糖主要由丝状蓝细菌分泌，它们是 BSC 的先驱和主要初级生产者。沙漠 BSC 在地球上最恶劣的环境之一中生存，并暴露在极端条件的日常波动中。居住在这些栖息地的蓝藻必须准确地读取不断变化的条件并预测例如即将发生的干燥。此外，他们发展出对多种适应策略的综合调控，以增强他们的压力耐受性。在这里，我们专注于区分能够在脱水后恢复的蓝细菌与那些不能恢复的蓝细菌的区别。虽然在我们对生理、生化和组学方面的理解方面取得了重要进展，但对能够耐受干燥的传感、信号转导和响应的澄清才刚刚出现。我们绘制了当前研究的轨迹和未解决的问题，从水化/干燥循环中的一般策略和调节适应，到我们对光合适应的理解的最新进展。获得的知识为缓解荒漠化和提高干旱条件下的植物生产力提供了新的见解。支持干燥耐受性的信号转导和反应才刚刚出现。我们绘制了当前研究的轨迹和未解决的问题，从水化/干燥循环中的一般策略和调节适应，到我们对光合适应的理解的最新进展。获得的知识为缓解荒漠化和提高干旱条件下的植物生产力提供了新的见解。支持干燥耐受性的信号转导和反应才刚刚出现。我们绘制了当前研究的轨迹和未解决的问题，从水化/干燥循环中的一般策略和调节适应，到我们对光合适应的理解的最新进展。获得的知识为缓解荒漠化和提高干旱条件下的植物生产力提供了新的见解。