scholarly journals The Nexus between Fire and Soil Bacterial Diversity in the African Miombo Woodlands of Niassa Special Reserve, Mozambique

2021 ◽  
Vol 9 (8) ◽  
pp. 1562
Author(s):  
Ivete Sandra Alberto Maquia ◽  
Paula Fareleira ◽  
Isabel Videira e. Castro ◽  
Ricardo Soares ◽  
Denise R. A. Brito ◽  
...  

(1) Background: the Miombo woodlands comprise the most important vegetation from southern Africa and are dominated by tree legumes with an ecology highly driven by fires. Here, we report on the characterization of bacterial communities from the rhizosphere of Brachystegia boehmii in different soil types from areas subjected to different regimes. (2) Methods: bacterial communities were identified through Illumina MiSeq sequencing (16S rRNA). Vigna unguiculata was used as a trap to capture nitrogen-fixing bacteria and culture-dependent methods in selective media were used to isolate plant growth promoting bacteria (PGPB). PGP traits were analysed and molecular taxonomy of the purified isolates was performed. (3) Results: Bacterial communities in the Miombo rhizosphere are highly diverse and driven by soil type and fire regime. Independent of the soil or fire regime, the functional diversity was high, and the different consortia maintained the general functions. A diverse pool of diazotrophs was isolated, and included symbiotic (e.g., Mesorhizobium sp., Neorhizobium galegae, Rhizobium sp., and Ensifer adhaerens), and non-symbiotic (e.g., Agrobacterium sp., Burkholderia sp., Cohnella sp., Microvirga sp., Pseudomonas sp., and Stenotrophomonas sp.) bacteria. Several isolates presented cumulative PGP traits. (4) Conclusions: Although the dynamics of bacterial communities from the Miombo rhizosphere is driven by fire, the maintenance of high levels of diversity and functions remain unchanged, constituting a source of promising bacteria in terms of plant-beneficial activities such as mobilization and acquisition of nutrients, mitigation of abiotic stress, and modulation of plant hormone levels.

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Raoudha Ferjani ◽  
Ramona Marasco ◽  
Eleonora Rolli ◽  
Hanene Cherif ◽  
Ameur Cherif ◽  
...  

In arid ecosystems environmental factors such as geoclimatic conditions and agricultural practices are of major importance in shaping the diversity and functionality of plant-associated bacterial communities. Assessing the influence of such factors is a key to understand (i) the driving forces determining the shape of root-associated bacterial communities and (ii) the plant growth promoting (PGP) services they provide. Desert oasis environment was chosen as model ecosystem where agriculture is possible by the microclimate determined by the date palm cultivation. The bacterial communities in the soil fractions associated with the root system of date palms cultivated in seven oases in Tunisia were assessed by culture-independent and dependent approaches. According to 16S rRNA gene PCR-DGGE fingerprinting, the shapes of the date palm rhizosphere bacterial communities correlate with geoclimatic features along a north-south aridity transect. Despite the fact that the date palm root bacterial community structure was strongly influenced by macroecological factors, the potential rhizosphere services reflected in the PGP traits of isolates screenedin vitrowere conserved among the different oases. Such services were exerted by the 83% of the screened isolates. The comparable numbers and types of PGP traits indicate their importance in maintaining the plant functional homeostasis despite the different environmental selection pressures.


Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 912
Author(s):  
Shuming Liu ◽  
Hongmei Liu ◽  
Rui Chen ◽  
Yong Ma ◽  
Bo Yang ◽  
...  

Miscanthus spp. are energy plants and excellent candidates for phytoremediation approaches of metal(loid)s-contaminated soils, especially when combined with plant growth-promoting bacteria. Forty-one bacterial strains were isolated from the rhizosphere soils and roots tissue of five dominant plants (Artemisia argyi Levl., Gladiolus gandavensis Vaniot Houtt, Boehmeria nivea L., Veronica didyma Tenore, and Miscanthus floridulus Lab.) colonizing a cadmium (Cd)-contaminated mining area (Huayuan, Hunan, China). We subsequently tested their plant growth-promoting (PGP) traits (e.g., production of indole-3-acetic acid, siderophore, and 1-aminocyclopropane-1-carboxylate deaminase) and Cd tolerance. Among bacteria, two strains, Klebsiella michiganensis TS8 and Lelliottia jeotgali MR2, presented higher Cd tolerance and showed the best results regarding in vitro growth-promoting traits. In the subsequent pot experiments using soil spiked with 10 mg Cd·kg−1, we investigated the effects of TS8 and MR2 strains on soil Cd phytoremediation when combined with M. floridulus (Lab.). After sixty days of planting M. floridulus (Lab.), we found that TS8 increased plant height by 39.9%, dry weight of leaves by 99.1%, and the total Cd in the rhizosphere soil was reduced by 49.2%. Although MR2 had no significant effects on the efficiency of phytoremediation, it significantly enhanced the Cd translocation from the root to the aboveground tissues (translocation factor > 1). The combination of K. michiganensis TS8 and M. floridulus (Lab.) may be an effective method to remediate Cd-contaminated soils, while the inoculation of L. jeotgali MR2 may be used to enhance the phytoextraction potential of M. floridulus.


2020 ◽  
Vol 96 (7) ◽  
Author(s):  
Hidehiro Ishizawa ◽  
Masashi Kuroda ◽  
Daisuke Inoue ◽  
Masaaki Morikawa ◽  
Michihiko Ike

ABSTRACT Plant growth-promoting bacteria (PGPB) have recently been demonstrated as a promising agent to improve wastewater treatment and biomass production efficiency of duckweed hydrocultures. With a view to their reliable use in aqueous environments, this study analysed the plant colonization dynamics of PGPB and the ecological consequences for the entire duckweed-associated bacterial community. A PGPB strain, Aquitalea magnusonii H3, was inoculated to duckweed at different cell densities or timings in the presence of three environmental bacterial communities. The results showed that strain H3 improved duckweed growth by 11.7–32.1% in five out of nine experiments. Quantitative-PCR and amplicon sequencing analyses showed that strain H3 successfully colonized duckweed after 1 and 3 d of inoculation in all cultivation tests. However, it significantly decreased in number after 7 d, and similar bacterial communities were observed on duckweed regardless of H3 inoculation. Predicted metagenome analysis suggested that genes related to bacterial chemotactic motility and surface attachment systems are consistently enriched through community assembly on duckweed. Taken together, strain H3 dominantly colonized duckweed for a short period and improved duckweed growth. However, the inoculation of the PGPB did not have a lasting impact due to the strong resilience of the natural duckweed microbiome.


Horticulturae ◽  
2020 ◽  
Vol 6 (4) ◽  
pp. 81
Author(s):  
Ahsanul Salehin ◽  
Md Hafizur Rahman Hafiz ◽  
Shohei Hayashi ◽  
Fumihiko Adachi ◽  
Kazuhito Itoh

Sweet potato (Ipomoea batatas L.) grows well even in infertile and nitrogen-limited fields, and endophytic bacterial communities have been proposed to be responsible for this ability. Plant-growth-promoting bacteria are considered eco-friendly and are used in agriculture, but their application can interact with endophytic communities in many ways. In this study, a commercial biofertilizer, OYK, consisting of a Bacillus sp., was applied to two cultivars of sweet potato, and the effects on indigenous endophytic bacterial communities in field conditions were examined. A total of 101 bacteria belonging to 25 genera in 9 classes were isolated. Although the inoculated OYK was not detected and significant plant-growth-promoting effects were not observed, the inoculation changed the endophytic bacterial composition, and the changes differed between the cultivars, as follows: Novosphingobium in α-Proteobacteria was dominant; it remained dominant in Beniharuka after the inoculation of OYK, while it disappeared in Beniazuma, with an increase in Sphingomonas and Sphingobium in α-Proteobacteria as well as Chryseobacterium and Acinetobacter in Flavobacteria. The behavior of Bacilli and Actinobacteria also differed between the cultivars. The Shannon diversity index (H) increased after inoculation in all conditions, and the values were similar between the cultivars. Competition of the inoculant with indigenous rhizobacteria and endophytes may determine the fates of the inoculant and the endophytic community.


2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Yong Li ◽  
YiXin Ying ◽  
WanLong Ding

The bacterial communities of 1- to 6-year ginseng rhizosphere soils were characterized by culture-independent approaches, random amplified polymorphic DNA (RAPD), and amplified ribosomal DNA restriction analysis (ARDRA). Culture-dependent method (Biolog) was used to investigate the metabolic function variance of microbe living in rhizosphere soil. Results showed that significant genetic and metabolic function variance were detected among soils, and, with the increasing of cultivating years, genetic diversity of bacterial communities in ginseng rhizosphere soil tended to be decreased. Also we found thatVerrucomicrobia,Acidobacteria, andProteobacteriawere the dominants in rhizosphere soils, but, with the increasing of cultivating years, plant disease prevention or plant growth promoting bacteria, such asPseudomonas,Burkholderia, andBacillus, tended to be rare.


mBio ◽  
2015 ◽  
Vol 6 (2) ◽  
Author(s):  
Iratxe Zarraonaindia ◽  
Sarah M. Owens ◽  
Pamela Weisenhorn ◽  
Kristin West ◽  
Jarrad Hampton-Marcell ◽  
...  

ABSTRACTGrapevine is a well-studied, economically relevant crop, whose associated bacteria could influence its organoleptic properties. In this study, the spatial and temporal dynamics of the bacterial communities associated with grapevine organs (leaves, flowers, grapes, and roots) and soils were characterized over two growing seasons to determine the influence of vine cultivar, edaphic parameters, vine developmental stage (dormancy, flowering, preharvest), and vineyard. Belowground bacterial communities differed significantly from those aboveground, and yet the communities associated with leaves, flowers, and grapes shared a greater proportion of taxa with soil communities than with each other, suggesting that soil may serve as a bacterial reservoir. A subset of soil microorganisms, including root colonizers significantly enriched in plant growth-promoting bacteria and related functional genes, were selected by the grapevine. In addition to plant selective pressure, the structure of soil and root microbiota was significantly influenced by soil pH and C:N ratio, and changes in leaf- and grape-associated microbiota were correlated with soil carbon and showed interannual variation even at small spatial scales. Diazotrophic bacteria, e.g.,Rhizobiaceaeand Bradyrhizobium spp., were significantly more abundant in soil samples and root samples of specific vineyards. Vine-associated microbial assemblages were influenced by myriad factors that shape their composition and structure, but the majority of organ-associated taxa originated in the soil, and their distribution reflected the influence of highly localized biogeographic factors and vineyard management.IMPORTANCEVine-associated bacterial communities may play specific roles in the productivity and disease resistance of their host plant. Also, the bacterial communities on grapes have the potential to influence the organoleptic properties of the wine, contributing to a regional terroir. Understanding that factors that influence these bacteria may provide insights into management practices to shape and craft individual wine properties. We show that soil serves as a key source of vine-associated bacteria and that edaphic factors and vineyard-specific properties can influence the native grapevine microbiome preharvest.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Ameerah Bokhari ◽  
Magbubah Essack ◽  
Feras F. Lafi ◽  
Cristina Andres-Barrao ◽  
Rewaa Jalal ◽  
...  

AbstractPlant growth-promoting bacteria (PGPB) are known to increase plant tolerance to several abiotic stresses, specifically those from dry and salty environments. In this study, we examined the endophyte bacterial community of five plant species growing in the Thar desert of Pakistan. Among a total of 368 culturable isolates, 58 Bacillus strains were identified from which the 16 most divergent strains were characterized for salt and heat stress resilience as well as antimicrobial and plant growth-promoting (PGP) activities. When the 16 Bacillus strains were tested on the non-host plant Arabidopsis thaliana, B. cereus PK6-15, B. subtilis PK5-26 and B. circulans PK3-109 significantly enhanced plant growth under salt stress conditions, doubling fresh weight levels when compared to uninoculated plants. B. circulans PK3-15 and PK3-109 did not promote plant growth under normal conditions, but increased plant fresh weight by more than 50% when compared to uninoculated plants under salt stress conditions, suggesting that these salt tolerant Bacillus strains exhibit PGP traits only in the presence of salt. Our data indicate that the collection of 58 plant endophytic Bacillus strains represents an important genomic resource to decipher plant growth promotion at the molecular level.


2019 ◽  
Author(s):  
Priyanka Kumari ◽  
Binu M. Tripathi ◽  
Ram N. Singh ◽  
Anil K. Saxena ◽  
Rajeev Kaushik

AbstractLong-term irrigation of agricultural fields with distillery effluent (DE) may alter the physical, chemical and biological properties of the soil. Microorganisms are critical to the maintenance of soil health and productivity. However, the impact of DE irrigation on activity and taxonomy of soil microorganisms is poorly understood. Here we studied plant-growth-promoting (PGP) traits and taxonomic composition of bacterial communities in agricultural soil irrigated with DE in conjugation with irrigation water, using cultivation-dependent and - independent methods. Most of the bacterial isolates obtained from DE irrigated soil were found to display PGP traits (phosphate solubilization, siderophore, indolic compounds and ammonia production). Diverse bacterial taxa were found in both culturable bacterial community and 16S rRNA gene clone library, which belonged to bacterial phylaProteobacteria(Alpha-, Beta- and Gamma- subdivisions),Firmicutes, Actinobacteria, Acidobacteria, BacteroidetesandGemmatimonadates. Overall, these results indicate that PGP traits and taxonomic diversity of soil bacterial communities were not severely impacted by DE irrigation.


Author(s):  
Pooja Gupta ◽  
Minal Trivedi ◽  
Harsha Soni

Application of chemical fertilizer is an integral practice to optimize crop productivity, but the dominant use of chemical fertilizers contributes largely to the deterioration of the environment, leads to loss of soil fertility, increases pollution, and causes hazardous diseases. Hence, the chemical fertilizers, pesticides and other supplements are being replaced by the plant growth promoting bacteria (PGPB) due to their improved potency and environment friendly nature. Plant growth-promoting bacteria (PGPB) can enhance plant growth by a wide variety of mechanisms like Phosphate (P) solubilization, Potassium solubilisation, siderophore production, biological nitrogen fixation and Indole acetic acid (IAA) production. The Klebsiella species is also known to exhibit important PGP traits like solubilization of phosphate, phytohormone production and good germination potential. In present study the Klebsiella pneumoniae PNE1 was selected from the isolates obtained from vegetable waste collected from Kadi market. The isolate was selected on the basis of its ability for Nitogen fixation, Phosphate solubilization, Potassium solubilization, IAA production, EPS production and biopolymer degradation. The molecular identification through 16S rRNA gene sequence, confirmed the isolate as Klebsiella pneumonia PNE1. Quantitative analysis of ammonia production revealed that isolate Klebsiella pneumonia PNE1 produced 0.5 µg/ml of ammonia (NH3) on 6th day of incubation and produced 0.09 µg/ml Nitrite after 8th day of incubation. The Phosphate solubilisation Index (SI) of the isolate was 4.16 and the isolate released 177.50 μg/ml Phosphate. The qualitative estimation of Potassium solubilisation by the isolate Klebsiella pneumoniae PNE1 in terms of Potassium solubilisation zone was found to increase gradually from day 1 to 7 days and was maximum at 2nd day with a KSI of 3.6. The isolate Klebsiella pneumoniae PNE1 released 29.94 mg/l Potassium on 21th day of incubation respectively. The IAA production was found to be 94.96 µg/ml. The maximum the EPS yield was 11.3 mg/ml. The Klebsiella pneumonia PNE1 had capacity to degrade Cellulose, Pectin and Xylan i.e. all biopolymers tested. The antibiotic susceptibility test indicated that isolate was sensitive to all 22 antibiotics tested. The Klebsiella pneumonia PNE1 thus, shows important plant growth promoting traits and can be used in a bio-fertilizer formulation for sustainable agriculture.


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