State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
College of Life Science and Technology, Xinjiang University, Urumqi, China.
Physiol Plant. 2024 Sep-Oct;176(5):e14510. doi: 10.1111/ppl.14510.
Soil salinization is a major environmental threat to the entire terrestrial ecosystem. Lichens arose from the symbiosis of fungi and algae or cyanobacteria. They have a high tolerance to various extreme environments, including adaptation to saline-alkali habitats. Thus, lichens are pioneer species on saline-alkali soil. However, the separate resilience of the two symbiotic partners under saline-alkali conditions remains insufficiently understood. In this study, two representative symbiotic algae, Diplosphaera chodatii and Trebouxia jamesii, were studied for their physiological response to the saline-alkali stress by adjusting different concentrations of NaHCO, together with their respective symbiotic fungi Endocarpon pusillum (terricolous lichen) and Umbilicaria muhlenbergii (saxicolous lichen). The results indicate that cell growth rate and biomass in all four cultures decreased in alkali-alkaline substrate, while cellular activities and ultrastructure were affected to a distinct extent. Compared with the symbiotic fungi, the algae were found to be more active in coordinating oxidative stress and lipid peroxidation damage under the saline-alkali stress. The antioxidant system of the alga was especially shown as a key adaptive trait and it provides an important strategy for species survival and persistence in arid saline-alkali desert. The specific survival ability of the lichen symbiosis relies on the stress resilience advantages of the symbiotic partners in combination. Our study provided new insights into understanding the adaptation of lichen symbiosis to desert saline-alkali soil, and the potential of lichen symbiotic algae in the future desert ecological restoration.
土壤盐渍化是整个陆地生态系统的主要环境威胁。地衣是真菌和藻类或蓝细菌共生的结果。它们对各种极端环境有很高的耐受性，包括适应盐碱生境。因此，地衣是盐碱土壤上的先锋物种。然而，在盐碱条件下，两个共生伙伴的单独恢复能力仍了解不足。在这项研究中，研究了两种代表性的共生藻类， Diplosphaera chodatii 和 Trebouxia jamesii ，通过调整不同浓度的 NaHCO ，研究它们对盐碱胁迫的生理响应，以及它们各自的共生真菌 Endocarpon pusillum （地衣）和 Umbilicaria muhlenbergii （石地衣）。结果表明，所有四种培养物的细胞生长率和生物量在碱性-碱性基质中均下降，而细胞活性和超微结构则受到明显影响。与共生真菌相比，藻类在盐碱胁迫下被发现更能协调氧化应激和脂质过氧化损伤。藻类的抗氧化系统特别表现为一种关键的适应特征，为物种在干旱盐碱荒漠中的生存和持续提供了重要策略。地衣共生体的特定生存能力依赖于共生伙伴在组合中的应激恢复优势。我们的研究为了解地衣共生体对荒漠盐碱土壤的适应提供了新的见解，并为未来荒漠生态恢复中地衣共生藻类的潜力提供了新的见解。
