Ait Bessai Sylia, Cruz Joana, Carril Pablo, Melo Juliana, Santana Margarida M, Mouazen Abdul M, Cruz Cristina, Yadav Ajar Nath, Dias Teresa, Nabti El-Hafid
Laboratoire de Maitrise des Energies Renouvelables, Faculté des Sciences de la Nature et de la Vie, Université de Bejaia, Bejaia 06000, Algeria.
cE3c-Centre for Ecology, Evolution and Environmental Changes and CHANGE-Global Change and Sustainability Institute, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal.
Microorganisms. 2023 Jun 28;11(7):1687. doi: 10.3390/microorganisms11071687.
(1) Background: Increasing salinity, further potentiated by climate change and soil degradation, will jeopardize food security even more. Therefore, there is an urgent need for sustainable agricultural practices capable of maintaining high crop yields despite adverse conditions. Here, we tested if wheat, a salt-sensitive crop, could be a good reservoir for halotolerant bacteria with plant growth-promoting (PGP) capabilities. (2) Methods: We used two agricultural soils from Algeria, which differ in salinity but are both used to grow wheat. Soil halotolerant bacterial strains were isolated and screened for 12 PGP traits related to phytohormone production, improved nitrogen and phosphorus availability, nutrient cycling, and plant defence. The four 'most promising' halotolerant PGPB strains were tested hydroponically on wheat by measuring their effect on germination, survival, and biomass along a salinity gradient. (3) Results: Two halotolerant bacterial strains with PGP traits were isolated from the non-saline soil and were identified as and , and another two halotolerant bacterial strains with PGP traits were isolated from the saline soil and identified as . When grown under 250 mM of NaCl, only the inoculated wheat seedlings survived. The halotolerant bacterial strain that displayed all 12 PGP traits and promoted seed germination and plant growth the most was one of the strains isolated from the saline soil. Although they both belonged to the clade and displayed a remarkable halotolerance, the two bacterial strains isolated from the saline soil differed in two PGP traits and had different effects on plant performance, which clearly shows that PGP potential is not phylogenetically determined. (4) Conclusions: Our data highlight that salt-sensitive plants and non-saline soils can be reservoirs for halotolerant microbes with the potential to become effective and sustainable strategies to improve plant tolerance to salinity. However, these strains need to be tested under field conditions and with more crops before being considered biofertilizer candidates.
(1) 背景：盐度上升，再加上气候变化和土壤退化的进一步加剧，将对粮食安全构成更大威胁。因此，迫切需要能在不利条件下维持高作物产量的可持续农业实践。在此，我们测试了对盐敏感的作物小麦是否能成为具有促进植物生长（PGP）能力的耐盐细菌的良好宿主。(2) 方法：我们使用了来自阿尔及利亚的两种农业土壤，它们的盐度不同，但都用于种植小麦。分离土壤耐盐细菌菌株，并针对与植物激素产生、改善氮磷有效性、养分循环和植物防御相关的12种PGP特性进行筛选。通过测量四种“最有前景”的耐盐PGPB菌株在盐度梯度下对小麦发芽、存活和生物量的影响，在水培条件下对其进行测试。(3) 结果：从非盐渍土壤中分离出两种具有PGP特性的耐盐细菌菌株，分别鉴定为 和 ，从盐渍土壤中分离出另外两种具有PGP特性的耐盐细菌菌株，鉴定为 。当在250 mM NaCl条件下生长时，只有接种的小麦幼苗存活。表现出所有12种PGP特性且对种子发芽和植物生长促进作用最大的耐盐细菌菌株是从盐渍土壤中分离出的 菌株之一。尽管它们都属于 进化枝且表现出显著的耐盐性，但从盐渍土壤中分离出的两种细菌菌株在两种PGP特性上有所不同，对植物性能的影响也不同，这清楚地表明PGP潜力并非由系统发育决定。(4) 结论：我们的数据表明，对盐敏感的植物和非盐渍土壤可以成为耐盐微生物的宿主，这有可能成为提高植物耐盐性的有效且可持续的策略。然而，在将这些菌株视为生物肥料候选物之前，需要在田间条件下和更多作物上进行测试。
