Halophytes can salinize soil when competing with glycophytes,intensifying effects of sea level rise in coastal communities

Sea level rise (SLR) and land-use change are working together to change coastal communities around the world. Along Florida’s coast, SLR and large-scale drying are increasing groundwater salinity, resulting in halophytic (salt-tolerant) species colonizing glycophytic (salt-intolerant) communities. We hypothesized that halophytes can contribute to increased soil salinity as they move into glycophyte communities, making soils more saline than SLR or drying alone. We tested our hypothesis with a replacement-series greenhouse experiment with halophyte/glycophyte ratios of 0:4, 1:3, 2:2, 3:1, 4:0, mimicking halophyte movement into glycophyte communities. We subjected replicates to 0, 26, and 38‰ salinity for one, one, and three months, respectively, taking soil salinity and stomatal conductance measurements at the end of each treatment period. Our results showed that soil salinity increased as halophyte/glycophyte ratio increased. Either osmotic or ionic stress caused decreases in glycophyte biomass, resulting in less per-plant transpiration as compared to halophytes. At 38‰ groundwater, soil salinity increased as halophyte density increased, making conditions more conducive to further halophyte establishment. This study suggests that coastal plant community turnover may occur faster than would be predicted from SLR and anthropogenic disturbance alone.     

干旱、半干旱区湖泊周围盐生植物群落的多样性格局及特点

干旱、半干旱地区湖泊周围是盐渍化土壤的主要分布区,盐渍化是荒漠化的主要类型之一。目前,关于盐生植被的分布格局及群落多样性随着盐渍化程度加深的动态变化的研究仍很缺乏, 为阐释这种关系,作者在内蒙古干旱、半干旱地区选择吉兰泰(盐池)、乌梁素海、查干诺尔(碱矿)以及额吉诺尔(盐池)等4个湖泊,研究了其周围盐生植物群落的物种组成、分布特征以及群落结构的差异, 讨论了群落多样性沿盐分梯度的变化特点, 并在此基础上探讨了盐生植物群落对土壤盐分环境的指示意义。为建立群落耐盐值与群落多样性的关系,我们计算了群落耐盐值。结果表明, 盐生植物群落沿盐湖呈明显的环带状分布;随着土壤盐渍化程度的增加, 按照芨芨草群落(Comm. Achnatherum splendens)、盐爪爪群落(Comm. Kalidium foliatum)、盐角草群落(Comm. Salicornia europaea)和碱蓬群落(Comm. Suaeda glauca)的顺序演替, 而且物种种类趋向单一化, 群落结构趋向简单化。群落的物种多样性和群落间物种的替代速率都随土壤盐分的增加而减小, 而群落间物种的相似性则增加。区域性气候特点对盐生植物群落的特征也会产生一定的影响, 特别是在低盐渍化的条件下, 这种影响比较显著, 使得盐生植物群落体现出地带性的特点, 而随着土壤盐渍化程度的提高, 盐生植物群落的隐域性特征更为突出。因此, 这一地区的盐生植被又呈现出非常明显的地带性植被向非地带性植被过渡的特点。     

塔里木盆地大叶白麻的土壤生境类型

 本文以新疆塔里木盆地大叶白麻在不同地形位置、土壤盐分含量和地下水位深浅等生态因子综合作用下,形成的土壤适应性反应为根据,结合所在土壤上的大叶白麻植株形态、生长状况和化学成分含量等特点,将该盆地大叶白麻的土壤划分为河漫滩草甸土、高水位盐土、中水位盐土、低水位盐土和砂化荒漠森林土五种生境类型;并建议按土壤生境类型来合理开发、利用和保护这一野生植物资源。     

Naturally Saline Boreal Communities as Models for Reclamation of Saline Oil Sand Tailings

Reclaimed landscapes after oil sands mining have saline soils; yet, they are required to have similar biodiversity and productivity as the predisturbance nonsaline landscape. Given that many species in the boreal forest are not tolerant of salinity, we studied the effects of soil salinity on plant communities in natural saline landscapes to understand potential plant responses during the reclamation process. Vegetation–soil relationships were measured along transects from flooded wetlands to upland forest vegetation in strongly saline, slightly saline, nonsaline, and reclaimed boreal landscapes. In strongly saline landscapes, surface soil salinity was high (>10 dS/m) in flooded, wet‐meadow, and dry‐meadow vegetation zones as compared to slightly saline (<5 dS/m) and nonsaline (<2 dS/m) landscapes. Plant communities in these vegetation zones were quite different from nonsaline boreal landscapes and were dominated by halophytes common to saline habitats of the Great Plains. In the shrub and forest vegetation zones, surface soil salinity was similar between saline and nonsaline landscapes, resulting in similar plant communities. In strongly saline landscapes, soils remained saline at depth through the shrub and forest vegetation zones (>10 dS/m), suggesting that forest vegetation can establish over saline soils as long as the salts are below the rooting zone. The reclaimed landscape was intermediate between slightly saline and nonsaline landscapes in terms of soil salinity but more similar to nonsaline habitats with respect to species composition. Results from this study suggest it may be unrealistic to expect that plant communities similar to those found on the predisturbance landscape can be established on all reclaimed landscapes after oil sands mining.     

Influence of edaphic factors on the spatial structure of inland halophytic communities: a case study in China

Abstract. In order to understand the influence of edaphic factors on the spatial structure of inland halophytic plant communities, a 2.6 km² study site, located on the lower fringe of the alluvial fan of the Hutubi River, in an arid region of China, was sampled and mapped. 105 patches were found to be homogeneous in species composition. Plant species and their coverage were recorded in each patch. 45 patches were randomly selected for the measurement of edaphic variables. A map with quadrat locations and boundaries of patches was digitized into a GIS and related to the vegetation and edaphic data matrices. CCA was used to evaluate the relative importance of edaphic factors in explaining the variation of the species assemblages and to identify the ecological preferences of species. The spatial structure of the communities and the main edaphic factors were analyzed using correlograms, Mantel correlograms and clustering under constraint of spatial contiguity. Gradient analysis showed that there are two distinct vegetation gradients in the study area, one of which is determined mainly by soil moisture (determined by depth to the water table), and the other by soil salinity (determined by electrical conductivity and hydrolytic alkalinity of the first soil layer). However, spatial analyses showed that at the sampling scale the halophytic communities in the study area are structured along one main spatial gradient determined by the water table level. Similar spatial autocorrelation structures between the factors related to the first soil layer and the communities, given our sampling scale, could not be detected. Our results suggest that the relative importance of the effects of different edaphic factors on the spatial structure of halophytic communities is scale-dependent. The partitioning of species variation indicates that in addition to edaphic factors, other factors, such as biotic interactions, may play an important role in structuring these communities.     

Diversity and salt tolerance of native Acacia rhizobia isolated from saline and non‐saline soils

Re‐establishing native vegetation in stressed soils is of considerable importance in many parts of the world, leading to significant interest in using plant–soil symbiont interactions to increase the cost‐effectiveness of large‐scale restoration. However, effective use of soil microbes in revegetation requires knowledge of how microbe communities vary along environmental stress gradients, as well as how such variation relates to symbiont effectiveness. In Australia, shrubby legumes dominate many ecosystems where dryland salinity is a major issue, and improving plant establishment in saline soils is a priority of regional management agencies. In this study, strains of rhizobial bacteria were isolated from a range of Acacia spp. growing in saline and non‐saline soils. Replicates of each strain were grown under several salinity levels in liquid culture and characterized for growth and salt tolerance. Genetic characterization of rhizobia showed considerable variation among strains, with salt tolerance and growth generally higher in rhizobial populations derived from more saline soils. These strains showed markedly different genetic profiles and generic affiliations to those from more temperate soils, suggesting community differentiation in relation to salt stress. The identification of novel genomic species from saline soils suggests that the diversity of rhizobia associated with Australian Acacia spp. is significantly greater than previously described. Overall, the ability of some symbiotically effective strains to tolerate high salinity is promising with regard to improving host plant re‐establishment in these soils.     

Small-scale resource heterogeneity among halophytic plant species in an upper salt marsh community

The focus of the present study was to determine whether spatial and temporal variation, in soil and plant factors of upper salt marsh areas, exists among microsites of three coexisting halophytic plant species, Grindelia humilis, Jaumea carnosa and Limonium californicum, on the Pacific coasts of California. Low frequencies in tidal inundations coupled with variation in temperature and rainfall patterns often result in wide seasonal salinity variations in these upper salt marsh zones. The study was carried out to evaluate (1) variation in soil osmolalities and soil water contents for the three species; (2) differences in chemical soil factors associated with the three species; (3) variation in leaf succulence associated with saline stress; and (4) levels of plant nutrients present in each of the three species. The results indicated that soil osmolalities associated with Limonium, a salt excreting halophyte were markedly different from those recorded for the other two species. Nitrogen levels in soils associated with Jaumea as well as levels in composite plant samples were significantly lower than those of the other two species. Also noted were variations in nutrient ions in plants as well as soil environments.     

Community‐level plant–soil feedbacks explain landscape distribution of native and non‐native plants

Plant–soil feedbacks (PSFs) have gained attention for their potential role in explaining plant growth and invasion. While promising, most PSF research has measured plant monoculture growth on different soils in short‐term, greenhouse experiments. Here, five soil types were conditioned by growing one native species, three non‐native species, or a mixed plant community in different plots in a common‐garden experiment. After 4 years, plants were removed and one native and one non‐native plant community were planted into replicate plots of each soil type. After three additional years, the percentage cover of each of the three target species in each community was measured. These data were used to parameterize a plant community growth model. Model predictions were compared to native and non‐native abundance on the landscape. Native community cover was lowest on soil conditioned by the dominant non‐native, Centaurea diffusa, and non‐native community cover was lowest on soil cultivated by the dominant native, Pseudoroegneria spicata. Consistent with plant growth on the landscape, the plant growth model predicted that the positive PSFs observed in the common‐garden experiment would result in two distinct communities on the landscape: a native plant community on native soils and a non‐native plant community on non‐native soils. In contrast, when PSF effects were removed, the model predicted that non‐native plants would dominate all soils, which was not consistent with plant growth on the landscape. Results provide an example where PSF effects were large enough to change the rank‐order abundance of native and non‐native plant communities and to explain plant distributions on the landscape. The positive PSFs that contributed to this effect reflected the ability of the two dominant plant species to suppress each other's growth. Results suggest that plant dominance, at least in this system, reflects the ability of a species to suppress the growth of dominant competitors through soil‐mediated effects.     

盐度对滨海土壤细菌多样性和群落构建过程的影响

滨海盐土是重要的农业土地后备资源.微生物是土壤中物质循环的关键动力,然而盐度对土壤微生物群落特征影响的研究还很缺乏.本研究采集滨海地区的土壤样品,研究非盐、轻盐和高盐3组不同盐度对土壤细菌数量、多样性和群落构建的影响.结果表明:与非盐和轻盐土壤相比,高盐土壤的脱氢酶活性和细菌数量显著降低,而细菌α多样性没有变化,细菌群...     

Evolutionary ecology of plant-microbe interactions: soil microbial structure alters selection on plant traits

? Below-ground microbial communities influence plant diversity, plant productivity, and plant community composition. Given these strong ecological effects, are interactions with below-ground microbes also important for understanding natural selection on plant traits? ? Here, we manipulated below-ground microbial communities and the soil moisture environment on replicated populations of Brassica rapa to examine how microbial community structure influences selection on plant traits and mediates plant responses to abiotic environmental stress. ? In soils with experimentally simplified microbial communities, plants were smaller, had reduced chlorophyll content, produced fewer flowers, and were less fecund when compared with plant populations grown in association with more complex soil microbial communities. Selection on plant growth and phenological traits also was stronger when plants were grown in simplified, less diverse soil microbial communities, and these effects typically were consistent across soil moisture treatments. ? Our results suggest that microbial community structure affects patterns of natural selection on plant traits. Thus, the below-ground microbial community can influence evolutionary processes, just as recent studies have demonstrated that microbial diversity can influence plant community and ecosystem processes.     

Plant growth response to direct and indirect temperature effects varies by vegetation type and elevation in a subarctic tundra

There has been growing recent use of elevational gradients as tools for assessing effects of temperature changes on vegetation properties, because these gradients enable temperature effects to be considered over larger spatial and temporal scales than is possible through conventional experiments. While many studies have explored the direct effects of temperature, the indirect effects of temperature through its long‐term influence on soil abiotic or biotic properties remain essentially unexplored. We performed two climate chamber experiments using soils from a subarctic elevational gradient in Abisko, Sweden to investigate the direct effects of temperature, and indirect effects of temperature via soil legacies, on growth of two grass species. The soils were collected from each of two vegetation types (heath, dominated by dwarf shrubs, and meadow, dominated by graminoids and herbs) at each of three elevations. We found that plants responded to both the direct effect of temperature and its indirect effect via soil legacies, and that direct and indirect effects were largely decoupled. Vegetation type was a major determinant of plant responses to both the direct and indirect effects of temperature; responses to soils from increasing elevation were stronger and showed a more linear decline for meadow than for heath soils. The influence of soil biota on plant growth was independent of elevation, with a positive influence across all elevations regardless of soil origin for meadow soils but not for heath soils. Taken together, this means that responses of plant growth to soil legacy effects of temperature across the elevational gradient were driven primarily by soil abiotic, and not biotic, factors. These findings emphasize that vegetation type is a strong determinant of how temperature variation across elevational gradients impacts on plant growth, and highlight the need for considering both direct and indirect effects of temperature on plant responses to future climate change.     

The changing nature of plant–microbe interactions during a biological invasion

Invasive plant species can alter belowground microbial communities. Simultaneously, the composition of soil microbial communities and the abundance of key microbes can influence invasive plant success. Such reciprocal effects may cause plant–microbe interactions to change rapidly during the course of biological invasions in ways that either inhibit or promote invasive species growth. Here we use a space-for-time substitution to illustrate how effects of soil microbial communities on the exotic legume Vicia villosa vary across uninvaded sites, recently invaded sites, and sites invaded by V. villosa for over a decade. We find that soil microorganisms from invaded areas increase V. villosa growth compared to sterilized soil or live soils collected from uninvaded sites, likely because mutualistic nitrogen-fixing rhizobia are not abundant in uninvaded areas. Notably, the benefits resulting from inoculation with live soils were higher for soils from recently invaded sites compared to older invasions, potentially indicating that over longer time scales, soil microbial communities change in ways that may reduce the success of exotic species. These findings suggest that short-term changes to soil microbial communities following invasion may facilitate exotic legume growth likely because of increases in the abundance of mutualistic rhizobia, but also indicate that longer term changes to soil microbial communities may reduce the growth benefits belowground microbial communities provide to exotic species. Our results highlight the changing nature of plant–microbe interactions during biological invasions and illustrate how altered biotic interactions could contribute to both the initial success and subsequent naturalization of invasive legume species.     

The fungal fast lane: common mycorrhizal networks extend bioactive zones of allelochemicals in soils

Allelopathy, a phenomenon where compounds produced by one plant limit the growth of surrounding plants, is a controversially discussed factor in plant-plant interactions with great significance for plant community structure. Common mycorrhizal networks (CMNs) form belowground networks that interconnect multiple plant species; yet these networks are typically ignored in studies of allelopathy. We tested the hypothesis that CMNs facilitate transport of allelochemicals from supplier to target plants, thereby affecting allelopathic interactions. We analyzed accumulation of a model allelopathic substance, the herbicide imazamox, and two allelopathic thiophenes released from Tagetes tenuifolia roots, by diffusion through soil and CMNs. We also conducted bioassays to determine how the accumulated substances affected plant growth. All compounds accumulated to greater levels in target soils with CMNs as opposed to soils without CMNs. This increased accumulation was associated with reduced growth of target plants in soils with CMNs. Our results show that CMNs support transfer of allelochemicals from supplier to target plants and thus lead to allelochemical accumulation at levels that could not be reached by diffusion through soil alone. We conclude that CMNs expand the bioactive zones of allelochemicals in natural environments, with significant implications for interspecies chemical interactions in plant communities.     

黄土高原四种人工植物群落土壤呼吸季节变化及其影响因子

以黄土高原侧柏、柠条、沙棘和油松人工植物群落为对象,土壤呼吸日动态和季节变化及其与环境因子之间的关系,结果表明:4种植物群落土壤呼吸速率具有典型的日变化和季节变化模式, 4种群落中,以侧柏6月土壤呼吸日变幅最大,沙棘6月土壤呼吸日变幅最小,大部分群落不同月份最大土壤呼吸与最小土壤呼吸倍数在1.1～1.6之间.4种群落中,以柠条土壤呼吸季节变幅最大,侧柏最小,最大土壤呼吸与最小土壤呼吸的倍数为1.5～2.2倍之间.同一植物类型土壤呼吸具有明显的季节变化特征,其具体变化趋势因植物类型而异.4种植物群落土壤呼吸速率与土壤和大气温度以及土壤含水量的关系在不同季节表现为不同的关系,其中侧柏和柠条土壤呼吸与土壤温度均呈乘幂关系,与大气温度为指数关系.沙棘土壤呼吸与土壤温度和大气温度均为乘幂关系,油松土壤呼吸与土壤温度和大气温度均为线性关系.这表明土壤呼吸与土壤和大气温度之间的关系及其紧密程度因植被类型而异.综合分析表明,同一气候区相同环境因子对不同植物群落土壤呼吸的影响作用不同,且因其自身具有明显的季节变化,从而导致对土壤呼吸的调控作用也具有明显的季节变异模式.     

内蒙古半干旱草原区沙地植物群落光合特征的动态研究

沙蒿(Artemisia intramongolica)群落是半干旱草原地区沙地的重要植被类型,分别在植物的生长前期、中期、盛期和后期采用便携式光合测定仪和大型同化分析仪测定了沙蒿叶片和沙蒿群落的光合动态。单叶和群落的光合速率日进程类型随气候的不同而异,瞬时光合速率主要决定于光合有效辐射强度(PAR)。土壤干旱大大降低了单叶和群落的光合能力,晴天土壤湿润时气温和空气湿度控制着叶片的光合速率,午间大气湿度降低是光合午休的主要外因。叶片的蒸腾速率与气温呈显著线性相关,植物的光能和水分利用效率也主要取决于PAR和气温,随着PAR和气温的升高利用效率下降。沙蒿叶片光能利用效率在后期也能保持较高水平。沙蒿对土壤干旱和高温具有一定的适应性,在土壤湿润时能迅速提高光合速率,形成较大的生物量。但是沙蒿的蒸腾速率高,水分利用效率低。研究认为,沙蒿通过对土壤干旱和高温的忍耐机制而保持长时间较高的光能利用效率,并在土壤湿润时迅速提高光合能力和积累干物质来适应半干旱的沙地环境,而且依靠高蒸腾速率和强的水分吸收能力来竞争性抑制其他植物的生长。     

Anthropogenic transformation of soil and vegetation resulting from afforestation in southern steppes

Recent data (2006–2008) on characteristics of the vegetation and soils of the solonetzic complex in areas with tree failures within the Volgograd-Elista-Cherkessk forest shelterbelt have been compared with those obtained prior to afforestation (1950). The results show that the vegetation and soils have changed profoundly. Solonetzic agrozems in tree failure sites have been occupied by herbaceous plant communities similar in composition to natural communities. Anthropogenically altered soils formed under forest plantations have no natural analogs. The initial strongly saline shallow (crusty) solonetz soils with a chloride-sulfate or sulfate-chloride composition of salts have transformed into slightly saline solonetzic and solonchakous agrozems with sodium sulfate salinity or with increased alkalinity in the middle of the soil profile and a dealkalized arable horizon.     

No consistent legacy effects of invasion by giant goldenrod (Solidago gigantea) via soil biota on native plant growth

Aims Changes in soil microbial communities after occupation by invasive alien plants can represent legacy effects of invasion that may limit recolonization and establishment of native plant species in soils previously occupied by the invader. In this study, for three sites in southern Germany, we investigated whether invasion by giant goldenrod (Solidago gigantea) leads to changes in soil biota that result in reduced growth of native plants compared with neighbouring uninvaded soils.Methods We grew four native plant species as a community and treated those plants with soil solutions from invaded or uninvaded soils that were sterilized, or live, with live solutions containing different fractions of the soil biota using a decreasing sieve mesh-size approach. We measured aboveground biomass of the plants in the communities after a 10-week growth period.Main Findings Across all three sites and regardless of invasion, communities treated with <20 μm soil biota or sterilized soil solutions had significantly greater biomass than communities treated with the complete soil biota solution. This indicates that soil biota>20 μm are more pathogenic to the native plants than smaller organisms in these soils. Across all three sites, there was only a non-significant tendency for the native community biomass to differ among soil solution types, depending on whether or not the soil was invaded. Only one site showed significant differences in community biomass among soil solution types, depending on whether or not the soil was invaded; community biomass was significantly lower when treated with the complete soil biota solution than with soil biota <20 μm or sterilized soil solutions, but only for the invaded soil. Our findings suggest that efforts to restore native communities on soils previously invaded by Solidago gigantea are unlikely to be hindered by changes in soil microbial community composition as a result of previous invasion.     

Salt tolerance mechanisms in quinoa (Chenopodium quinoa Willd.)

In the face of diminishing fresh water resources and increasing soil salinisation it is relevant to evaluate the potential of halophytic plant species to be cultivated in arid and semi-arid regions, where the productivity of most crop plants is markedly affected. Quinoa is a facultative halophytic plant species with the most tolerant varieties being able to cope with salinity levels as high as those present in sea water. This characteristic has aroused the interest in the species, and a number of studies have been performed with the aim of elucidating the mechanisms used by quinoa in order to cope with high salt levels in the soil at various stages of plant development. In quinoa key traits seem to be an efficient control of Na⁺ sequestration in leaf vacuoles, xylem Na⁺ loading, higher ROS tolerance, better K⁺ retention, and an efficient control over stomatal development and aperture. The purpose of this review is to give an overview on the existing knowledge of the salt tolerance of quinoa, to discuss the potential of quinoa for cultivation in salt-affected regions and as a basis for further research in the field of plant salt tolerance.     

Root-zone constraints and plant-based solutions for dryland salinity

Limitations to agricultural productivity imposed by the root-zone constraints in Australian dryland soils are severe and need redemption to improve the yields of grain crops and thereby meet world demand. Physical, chemical and biological constraints in soil horizons impose a stress on the plant and restrict plant growth and development. Hardsetting, crusting, compaction, salinity, sodicity, acidity, alkalinity, nutrient deficiencies and toxicities due to boron, carbonates and aluminium are the major factors that cause these constraints. Further, subsoils in agricultural regions in Australia have very low organic matter and biological activity. Dryland salinity is currently given wide attention in the public debate and government policies in Australia, but they only focus on salinity induced by shallow groundwater. However, the occurrence of transient salinity in root-zone layers in the regions where water tables are deep is an important issue with potential for larger economic loss than water table-induced seepage salinity. Root-zone constraints pose a challenge for salinity mitigation in recharge as well as discharge zones. In recharge zones, reduced water movement in sodic horizons results in salt accumulation in the root zone resulting in chemical and physical constraints that reduce transpiration that, in turn, upsets salt balance and plant growth. High salinity in soil and groundwater restricts the ability of plants to reduce water table in discharge zones. Thus plant-based strategies must address different kinds of limitations in soil profiles, both in recharge and discharge zones. In this paper we give an overview of plant response to root-zone constraints but with an emphasis on the processes of salt accumulation in the root-zone of soils. We also examine physical and chemical methods to overcome subsoil limitations, the ability of plants to adapt to and ameliorate these constraints, soil modification by management of agricultural and forestry ecosystems, the use of biological activity, and plant breeding for resistance to the soil constraints. We emphasise that soil scientists in cooperation with agronomists and plant breeders should design site-specific strategies to overcome multiple soil constraints, with vertical and lateral variations, and to develop plant-based solutions for dryland salinity.     

Effect of Bacillus mesonae H20-5 Treatment on Rhizospheric Bacterial Community of Tomato Plants under Salinity Stress

Plant growth-promoting bacteria improve plant growth under abiotic stress conditions. However, their effects on microbial succession in the rhizosphere are poorly understood. In this study, the inoculants of Bacillus mesonae strain H20-5 were administered to tomato plants grown in soils with different salinity levels (EC of 2, 4, and 6 dS/m). The bacterial communities in the bulk and rhizosphere soils were examined 14 days after H20-5 treatment using Illumina MiSeq sequencing of the bacterial 16S rRNA gene. Although the abundance of H20-5 rapidly decreased in the bulk and rhizosphere soils, a shift in the bacterial community was observed following H20-5 treatment. The variation in bacterial communities due to H20-5 treatment was higher in the rhizosphere than in the bulk soils. Additionally, the bacterial species richness and diversity were greater in the H20-5 treated rhizosphere than in the control. The composition and structure of the bacterial communities varied with soil salinity levels, and those in the H20-5 treated rhizosphere soil were clustered. The members of Actinobacteria genera, including Kineosporia, Virgisporangium, Actinoplanes, Gaiella, Blastococcus, and Solirubrobacter, were enriched in the H20-5 treated rhizosphere soils. The microbial co-occurrence network of the bacterial community in the H20-5 treated rhizosphere soils had more modules and keystone taxa compared to the control. These findings revealed that the strain H20-5 induced systemic tolerance in tomato plants and influenced the diversity, composition, structure, and network of bacterial communities. The bacterial community in the H20-5 treated rhizosphere soils also appeared to be relatively stable to soil salinity changes.