Alghamdi Amal Khalaf, Parween Sabiha, Hirt Heribert, Saad Maged M
DARWIN21, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia.
Department of Botany and Microbiology, College of Science, King Saud University, P.O. Box 2455, Riyadh, 11451, Saudi Arabia.
Environ Microbiome. 2024 Dec 4;19(1):101. doi: 10.1186/s40793-024-00642-w.
Avicennia marina ecosystems are critical for coastal protection, water quality enhancement, and biodiversity support. These unique ecosystems thrive in extreme saline conditions and host a diverse microbiome that significantly contributes to plant resilience and growth. Global food security is increasingly threatened by crop yield losses due to abiotic stresses, including saline soils. Traditional plant breeding for salt tolerance is both costly and time-consuming. This study explores the potential of bacteria from A. marina to enhance plant growth under saline conditions, emphasizing their ecological significance.
We analyzed the microbiome of A. marina from the Red Sea coast using high-throughput Illumina sequencing and culture-dependent methods across various compartments (bulk soil, rhizosphere, rhizoplane, roots, and leaves). Our findings revealed distinct compartment-specific microbial communities, with Proteobacteria being the dominant phylum. Functional predictions indicated diverse microbial roles in metal uptake and plant growth promotion (PGP). Remarkably, our culture-dependent methods allowed us to recover 56% of the bacterial diversity present in the microbiome, resulting in the isolation and characterization of 256 bacterial strains. These isolates were screened for PGP traits, including salt and heat tolerance, siderophore production, and pectinase activity. Out of the 77 bacterial isolates tested, 11 demonstrated a significant ability to enhance Arabidopsis growth under salt stress.
Our study highlights the ecological significance of mangrove microbiomes and the potential of culture collections in offering innovative solutions for ecological restoration and crop production in saline conditions. The unique collection of mangrove bacteria, particularly from the rhizosphere and endophytes, showcases significant PGP traits and stress tolerance capabilities. These findings emphasize the importance of functional traits, such as salt tolerance, in the recruitment of endophytic bacteria by plants over taxonomic affiliation. The identified bacterial strains hold potential not only for developing biofertilizers to improve crop productivity but also for ecological restoration projects aimed at rehabilitating saline-degraded lands, thereby contributing to overall ecosystem health and sustainability.
白骨壤生态系统对于海岸保护、水质改善和生物多样性维持至关重要。这些独特的生态系统在极端盐碱条件下蓬勃发展，并拥有多样的微生物群落，对植物的恢复力和生长有显著贡献。全球粮食安全日益受到包括盐渍土在内的非生物胁迫导致的作物产量损失的威胁。传统的耐盐植物育种既昂贵又耗时。本研究探讨了白骨壤细菌在盐碱条件下促进植物生长的潜力，并强调了它们的生态意义。
我们使用高通量Illumina测序和基于培养的方法，对红海沿岸白骨壤的各个部分（土壤、根际、根表、根和叶）的微生物群落进行了分析。我们的研究结果揭示了不同部分特有的微生物群落，变形菌门是主要的门类。功能预测表明微生物在金属吸收和植物生长促进（PGP）方面具有多种作用。值得注意的是，我们基于培养的方法使我们能够回收微生物群落中56%的细菌多样性，从而分离并鉴定了256株细菌菌株。对这些分离株进行了PGP特性筛选，包括耐盐性和耐热性、铁载体产生和果胶酶活性。在测试的77株细菌分离株中，有11株在盐胁迫下显著促进了拟南芥的生长。
我们的研究突出了红树林微生物群落的生态意义，以及培养物收集在为盐碱条件下的生态恢复和作物生产提供创新解决方案方面的潜力。独特的红树林细菌收集，特别是来自根际和内生菌的细菌，展示了显著的PGP特性和胁迫耐受能力。这些发现强调了功能特性，如耐盐性，在植物招募内生细菌方面比分类学归属更为重要。所鉴定的细菌菌株不仅具有开发生物肥料以提高作物生产力的潜力，还具有用于恢复盐碱退化土地的生态恢复项目的潜力，从而有助于整体生态系统的健康和可持续性。
