Salinity is one of the most important abiotic factors in various natural habitats of microbes. Cyanobacteria are the most widely distributed family of photosynthetic microorganisms in environments with fluctuating salinity. In response to salt stress, many cyanobacteria synthesize compatible solutes to maintain osmotic balance in the cell. However, the regulation of intracellular accumulation of these compounds is still not well understood. The freshwater cyanobacterium PCC 7942 (Syn7942) exclusively accumulates sucrose as a compatible solute upon salt stress and is thus an ideal model microorganism for studying the metabolism of compatible solute dynamics. Here, we focused on elucidating the regulatory mechanisms involved in salt-induced sucrose accumulation in Syn7942. Using a series of physiological and biochemical experiments, we showed that the ionic effect of salt stress plays an important role in inducing sucrose synthesis, whereby elevated ion concentration directly activates the sucrose-synthesizing enzyme sucrose-phosphate synthase and simultaneously inhibits the sucrose-degrading enzyme invertase, resulting in a rapid sucrose accumulation. Thus, we propose a novel mechanism for cyanobacterial adaption to salt stress and fluctuating salinity, i.e., the ion-induced synergistic modulation of the enzymes synthesizing and degrading compatible solutes. These findings greatly enhance our current understanding of microbial adaptation to salt. Most microbes synthesize compatible solutes for adaptation to salt stress or fluctuating salinity environments. However, to date, one of the core questions involved in these physiological processes, i.e., the regulation of salt-induced compatible solute biosynthesis, is still not well understood. Here, this issue was systematically investigated by employing the model freshwater cyanobacterium PCC 7942. A novel mechanism for cyanobacterial adaption to salt stress and fluctuating salinity, i.e., the ion-induced synergistic modulation of key synthesizing and degrading enzymes of compatible solutes, is proposed. Because the ion-induced activation/inhibition of enzymes is a fast and efficient process, it may represent a common strategy of microbes for adaptation to environments with fluctuating salinity.
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http://dx.doi.org/10.1128/AEM.02904-19 | DOI Listing |
Front Plant Sci
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Institute of Vegetables, Anhui Academy of Agricultural Sciences, Hefei, China.
Introduction: Melatonin significantly enhances the tolerance of plants to biotic and abiotic stress, and plays an important role in plant resistance to salt stress. However, its role and molecular mechanisms in eggplant salt stress resistance have been rarely reported. In previous studies, we experimentally demonstrated that melatonin can enhance the salt stress resistance of eggplants.
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State Key Laboratory of Crop Gene Resources and Breeding/Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, South Zhong-Guan-Cun Street 12#, Beijing, 100081, China.
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View Article and Find Full Text PDFJ Plant Physiol
January 2025
School of Life Sciences, Qinghai Normal University, Xining, 810008, China.
Rheum tanguticum, an endemic species from the Qinghai-Xizang Plateau, is a significant perennial and medicinal plant recognized for its robust resistance to abiotic stresses, including drought, cold, and salinity. To advance the understanding of stress-response mechanisms in R. tanguticum, this study aimed to establish a reliable set of housekeeping genes as references for normalizing RT-qPCR gene expression analyses.
View Article and Find Full Text PDFPlant Physiol Biochem
January 2025
Universidade Federal de Campina Grande, Center for Technology and Natural Resources, Campina Grande, 58429-000, Brazil.
Guava is a fruit crop widely exploited in the Northeast region of Brazil. However, its exploitation is limited by water scarcity and, in many cases, producers are forced to use water with high levels of salts in irrigation. Thus, it is necessary to develop techniques to induce plant tolerance to salt stress, and the foliar application of a non-enzymatic compound such as ascorbic acid is a promising alternative to mitigate the deleterious effects on plants.
View Article and Find Full Text PDFBMC Genomics
January 2025
Henan Collaborative Innovation Center of Modern Biological Breeding, College of Agronomy, Henan Institute of Science and Technology, Xinxiang, 453003, China.
Background: The Sec14 domain is an ancient lipid-binding domain that evolved from yeast Sec14p and performs complex lipid-mediated regulatory functions in subcellular organelles and intracellular traffic. The Sec14 family is characterized by a highly conserved Sec14 domain, and is ubiquitously expressed in all eukaryotic cells and has diverse functions. However, the number and characteristics of Sec14 homologous genes in soybean, as well as their potential roles, remain understudied.
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