scholarly journals Rice Root-Associated Diazotrophic Community Succession is Driven by Growth Period Combined With Fertilization

2020 ◽  
Author(s):  
Zhongli Cui ◽  
Xue Luo ◽  
Xianfeng Ye ◽  
Wenhui Wang ◽  
Yang Chen ◽  
...  
Keyword(s):  
Community Composition ◽  
Soil Nutrients ◽  
Rhizosphere Soil ◽  
Growth Period ◽  
Reproductive Stage ◽  
Vegetative Stage ◽  
Pig Manure ◽  
Community Structures ◽  
Relative Abundances ◽  
Diazotrophic Community

Abstract BackgroundBiological nitrogen fixation (BNF) and nitrogenous fertilizers are two crucial ways for nitrogen input in the rice paddy system. Little is known about the effect of nitrogenous fertilizers on root-associated diazotrophs. Here, we investigated the succession of total and active diazotrophs in rhizosphere soil and rice roots under four fertilization treatments (control, NPK, NPK + pig manure, and NPK + rice straw) during three key growth periods (tillering, heading and mature).ResultsThe 15N isotope dilution experiment verified that root-associated diazotrophs could supply N for rice under low nitrogen nutrition by BNF (%Ndfa=11.51). Niche differentiation of diazotrophs existed at the rhizosphere soil-root interface. At both DNA and RNA levels, growth period had stronger effects on the community composition of endophytic diazotrophs than rhizosphere diazotrophs. The Chao1 and Shannon indices of total endophytic diazotrophs dramatically increased at the vegetative stage, and underwent relatively minor changes at the reproductive stage. Furthermore, the community structures of total endophytic diazotrophs were more stabilized in the reproductive stage than the vegetative stage. The number of OTUs shared by rhizosphere soil and roots increased during rice growth. Compared with CK, NPK reduced the relative abundances of Pelobacter and increased the relative abundances of Azoarcus. Pig manure not only improved soil nutrients (OM, TN, TP, AN, AP and NO3-N), but reduced the effect of chemical fertilizers on the community composition of natural rhizosphere diazotrophs. ConclusionsGrowth period demonstrated a stronger influence on the root-associated diazotrophs than fertilization practices. The community structures of total endophytic diazotrophs were more stabilized in the reproductive stage than the vegetative stage, and the alpha-diversity indices and complex of network structures of endophytic diazotrophs increased at the vegetative stage. Replacing chemical fertilization with pig manure not only increased soil nutrients, but regulated rhizosphere diazotrophic community structures. Understanding the combined effects of growth period and fertilization on root-associated diazotrophs presents the basis towards the sustainable crop production.

Grazing intensity rather than host plant’s palatability shape the community of arbuscular mycorrhizal fungi in a steppe grassland

2021 ◽  
Author(s):  
Maede Faghihinia ◽  
Yi Zou ◽  
Yongfei Bai ◽  
Martin Dudáš ◽  
Rob Marrs ◽  
...  
Keyword(s):  
Arbuscular Mycorrhizal Fungi ◽  
Community Composition ◽  
Mycorrhizal Fungi ◽  
Rhizosphere Soil ◽  
Grazing Intensity ◽  
Arbuscular Mycorrhizal ◽  
Grass Species ◽  
Α Diversity ◽  
Steppe Grassland

Abstract Arbuscular mycorrhizal fungi (AMF) are the predominant type of mycorrhizal fungi in roots and rhizosphere soil of grass species worldwide. Grasslands are currently experiencing increasing grazing pressure, but it is not yet clear how grazing intensity and host plant grazing preference by large herbivores interact with soil- and root-associated AMF communities. Here, we tested whether the diversity and community composition of AMF in the roots and rhizosphere soil of two dominant perennial grasses grazed differently by livestock change in response to grazing intensity. We conducted a study in a long-term field experiment in which seven levels of field-manipulated grazing intensities were maintained for 13 years in a typical steppe grassland in northern China. We extracted DNA from the roots and rhizosphere soil of two dominant grasses, Leymus chinense (Trin.) Tzvel. and Stipa grandis P. Smirn, with contrasting grazing preference by sheep. AMF DNA from root and soil samples were then subjected to molecular analysis. Our results showed that AMF α-diversity (richness) at the virtual taxa (VT) level varied as a function of grazing intensity. Different VTs showed completely different responses along the gradient, one increasing, one decreasing and others showing no response. Glomeraceae was the most abundant AMF family along the grazing gradient, which fits well with the theory of disturbance tolerance of this group. In addition, sheep grazing preference for host plants did not explain a considerable variation in AMF α-diversity. However, the two grass species exhibited different community composition in their roots and rhizosphere soils. Roots exhibited a lower α-diversity and higher β-diversity within the AMF community than soils. Overall, our results suggest that long-term grazing intensity might have changed the abundance of functionally-diverse AMF taxa in favor of those with disturbance-tolerant traits. We suggest our results would be useful in informing the choice of mycorrhizal fungi indicator variables when assessing the impacts of grassland management choices on grassland ecosystem functioning.

scholarly journals Desempenho morfofisiológico de cultivares de soja de ciclo médio em condições de alagamento do solo

2017 ◽  
Vol 12 (3) ◽  
pp. 385
Author(s):  
Marcos Paulo Ludwig ◽  
Sandro De Oliveira ◽  
Luis Osmar Braga Schuch ◽  
Francisco Jesus Vernetti Junior ◽  
Rogério Seus ◽  
...  
Keyword(s):  
Plant Height ◽  
Reproductive Stage ◽  
Main Stem ◽  
Vegetative Stage ◽  
Cultivation Condition ◽  
Soil Flooding ◽  
Soybean Cultivars ◽  
Content Index ◽  
Crop Cycle ◽  
Stem Chlorophyll

<p>O aumento no cultivo de soja no Brasil têm atingido áreas antes utilizadas para outros fins, como em regiões de solos de várzea, estando assim, sujeita a eventuais alagamentos do solo. Este trabalho objetivou avaliar alterações morfofisiológicas em cultivares de soja de ciclo médio, em condições de alagamento do solo, nos estádios fenológicos vegetativo e reprodutivo para recomendação de cultivares. Os experimentos foram conduzidos na Estação Experimental de Terras Baixas, da Embrapa Clima Temperado em Capão do Leão, RS. Foram aplicados três sistemas de manejo da água: condição normal de cultivo (sem alagamento), alagamento no período vegetativo (V3/V4) e alagamento no período reprodutivo (R2/R3). As avaliações realizadas durante o ciclo da cultura foram: altura de plantas, diâmetro da haste principal, índice do teor de clorofila, fenologia e número de nós nas hastes por planta. O alagamento do solo reduz o número de nós na haste principal, reduzindo a estatura das plantas, sendo os efeitos mais acentuados quando o alagamento ocorre no estádio vegetativo. Além disso, o alagamento do solo no período reprodutivo promove aumento do diâmetro da haste principal. O alagamento do solo causa retardamento de ocorrência dos estádios fenológicos, bem como do ciclo total das cultivares de soja.</p><p align="center"><strong><em>Morphophysiological performance of medium cycle soybean cultivars under flooding</em></strong><strong><em></em></strong></p><pre><strong>Abstract: </strong>The increase in soybean cultivation in Brazil has reached areas previously used for other purposes, such as in regions of lowland soils, thus being subject to possible soil flooding. This study aimed to evaluate morphophysiological changes in medium cycle soybean cultivars, under soil flooding conditions, in the vegetative and reproductive stages to recommend cultivars.<strong> </strong>The experiments were conducted at the Estação Experimental de Terras Baixas, EMBRAPA Clima Temperado in the Capão do Leão city, RS. Three water management systems were applied: normal cultivation condition (without flooding), flooding in the vegetative stage (V3 / V4) and flooding during the reproductive stage (R2 / R3). During the crop cycle, plant height, diameter of the main stem, chlorophyll content index, phenology and number of nodes in the stem per plant were collected. On the basis of the results this study, it can be concluded that he flooding reduces the number of nodes on the main stem, reducing plant height, with the most pronounced effects when flooding occurs in the vegetative stage. Furthermore, flooding the reproductive stage promotes increased diameter of the main stem. Flooding causes delay of occurrence of phenological stages and the total cycle of soybean cultivars.</pre>

scholarly journals Differential Expression of Benzophenone Synthase and Chalcone Synthase in Hypericum Sampsonii

2012 ◽  
Vol 7 (12) ◽  
pp. 1934578X1200701 ◽  
Author(s):  
Lili Huang ◽  
Hong Wang ◽  
Hechun Ye ◽  
Zhigao Du ◽  
Yansheng Zhang ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Differential Expression ◽  
Chalcone Synthase ◽  
Quantitative Polymerase Chain Reaction ◽  
Transcript Level ◽  
Reproductive Stage ◽  
Vegetative Stage ◽  
Chain Reaction ◽  
Expression Levels ◽  
Polymerase Chain

cDNAs encoding Hypericum sampsonii benzophenone synthase (HsBPS) and chalcone synthase (HsCHS) were isolated and functionally characterized. Differential expressions of HsBPS and HsCHS were monitored using quantitative polymerase chain reaction (PCR). In the vegetative stage, HsBPS was highly expressed in the roots; its transcript level was approx. 100 times higher than that of HsCHS. Relatively high transcript amounts of HsBPS were also detected in older leaves, whereas the youngest leaves contained higher transcript amounts of HsCHS. In the reproductive stage, maximum HsCHS expression was detected in flowers, the transcript level being approx. 5 times higher than that of HsBPS. The inversed situation with a 10-fold difference in the expression levels was observed with fruits. High transcript amounts for both proteins were found in roots.

Analyses of Aerosol Concentrations and Bacterial Community Structures for Closed Cage Broiler Houses at Different Broiler Growth Stages in Winter

2018 ◽  
Vol 81 (9) ◽  
pp. 1557-1564
Author(s):  
LINLIN JIANG ◽  
JIANLONG ZHANG ◽  
JINXIU TANG ◽  
MENG LI ◽  
XIAOYU ZHAO ◽  
...  
Keyword(s):  
Bacterial Community ◽  
High Throughput ◽  
High Throughput Sequencing ◽  
Total Concentration ◽  
Growth Period ◽  
Growth Cycle ◽  
Growth Stages ◽  
Community Structures ◽  
Dynamic Pattern ◽  
Different Growth Stages

ABSTRACT The aim of the present study was to analyze the aerosol concentrations and microbial community structures in closed cage broiler houses at different broiler growth stages to assess the dynamic pattern of microbial aerosols in closed cage systems. Our results revealed that the total concentration of bacterial aerosols gradually increased during the growth cycle of broilers. High-throughput sequencing of 16S rDNA revealed that microbial compositions differed tremendously during different growth stages, although Firmicutes and Proteobacteria were the dominant taxa in samples from all broiler growth stages. At the genus level, dominant phylotypes displayed great variation during different growth stages. Escherichia and Shigella were the most dominant taxa throughout the growth cycle, increasing from 4.3 to 12.4% as the broilers grew. The alpha index revealed that the microbial diversity displayed significant differences between the different growth stages and that the bacterial community had the highest diversity when broilers were 22 days old. High-throughput sequencing analyses revealed that environmental microbes and opportunistic pathogens had relatively high abundances during the winter growth period. The data revealed the composition and aerodynamic diameters of microbial aerosols in closed cage broiler houses at different broiler growth stages in winter. The results also enabled us to elucidate the dynamic pattern of microbial aerosols in broiler houses in response to bacterial communities. Our results may provide a basis for developing technologies for air quality control in caged poultry houses.

scholarly journals Effects of Two Trichoderma Strains on Plant Growth, Rhizosphere Soil Nutrients, and Fungal Community of Pinus sylvestris var. mongolica Annual Seedlings

Forests ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 758 ◽  
Author(s):  
Saiyaremu Halifu ◽  
Xun Deng ◽  
Xiaoshuang Song ◽  
Ruiqing Song
Keyword(s):  
Enzyme Activity ◽  
Community Structure ◽  
Plant Growth ◽  
Soil Nutrients ◽  
Fungal Community ◽  
Rhizosphere Soil ◽  
Soil Nutrient ◽  
Nutrient Content ◽  
Root Structure ◽  
Soil Nutrient Content

Trichoderma spp. are proposed as major plant growth-promoting fungi that widely exist in the natural environment. These strains have the abilities of rapid growth and reproduction and efficient transformation of soil nutrients. Moreover, they can change the plant rhizosphere soil environment and promote plant growth. Pinus sylvestris var. mongolica has the characteristics of strong drought resistance and fast growth and plays an important role in ecological construction and environmental restoration. The effects on the growth of annual seedlings, root structure, rhizosphere soil nutrients, enzyme activity, and fungal community structure of P. sylvestris var. mongolica were studied after inoculation with Trichoderma harzianum E15 and Trichoderma virens ZT05, separately. The results showed that after inoculation with T. harzianum E15 and T. virens ZT05, seedling biomass, root structure index, soil nutrients, and soil enzyme activity were significantly increased compared with the control (p < 0.05). There were significant differences in the effects of T. harzianum E15 and T. virens ZT05 inoculation on the growth and rhizosphere soil nutrient of P. sylvestris var. mongolica (p < 0.05). For the E15 treatment, the seedling height, ground diameter, and total biomass of seedlings were higher than that those of the ZT05 treatment, and the rhizosphere soil nutrient content and enzyme activity of the ZT05 treatment were higher than that of the E15 treatment. The results of alpha and beta diversity analyses showed that the fungi community structure of rhizosphere soil was significantly different (p < 0.05) among the three treatments (inoculated with T. harzianum E15, T. virens ZT05, and not inoculated with Trichoderma). Overall, Trichoderma inoculation was correlated with the change of rhizosphere soil nutrient content.

scholarly journals High-methionine soybean has no significant effect on nitrogen-transforming bacteria in rhizosphere soil

2018 ◽  
Vol 64 (No. 3) ◽  
pp. 108-113 ◽  
Author(s):  
Liang Jingang ◽  
Luan Ying ◽  
Jiao Yue ◽  
Sun Shi ◽  
Wu Cunxiang ◽  
...  
Keyword(s):  
Community Composition ◽  
Rhizosphere Soil ◽  
Microbial Community Composition ◽  
Potential Effect ◽  
Ammonia Oxidizing Bacteria ◽  
Nitrogen Fixing ◽  
Transgenic Soybean ◽  
Bacterial Populations ◽  
Microbial Functional Groups ◽  
Microbial Groups

Transgenic plants may induce shifts in the microbial community composition that in turn alter microbially-mediated nutrient cycling in soil. Studies of how specific microbial groups respond to genetically modified (GM) planting help predict potential impacts upon processes performed by these groups. This study investigated the effect of transgenic high-methionine soybean cv. ZD91 on nitrogen-fixing and ammonia-oxidizing bacterial populations. A difference in nitrogen-fixing or ammonia-oxidizing bacteria community composition was not found, suggesting that cv. ZD91 does not alter the bacterial populations in rhizosphere soil. This study increases our understanding of the potential effect of transgenic soybean on microbial functional groups within soil by suggesting that nitrogen-transforming bacteria may be useful for future investigations on the GM crops impact in the soil ecosystem.

scholarly journals Bacterial Community of the Rice Floodwater Using Cultivation-Independent Approaches

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Michele Pittol ◽  
Erin Scully ◽  
Daniel Miller ◽  
Lisa Durso ◽  
Lidia Mariana Fiuza ◽  
...  
Keyword(s):  
Bacterial Communities ◽  
Developmental Stages ◽  
Amplicon Sequencing ◽  
Fertilizer Application ◽  
Rice Fields ◽  
Reproductive Stage ◽  
Vegetative Stage ◽  
Bacterial Phyla ◽  
16S Amplicon Sequencing ◽  
South Of Brazil

In agricultural systems, interactions between plants and microorganisms are important to maintaining production and profitability. In this study, bacterial communities in floodwaters of rice fields were monitored during the vegetative and reproductive stages of rice plant development using 16S amplicon sequencing. The study was conducted in the south of Brazil, during the crop years 2011/12 and 2012/13. Comparative analyses showed strong differences between the communities of floodwaters associated with the two developmental stages. During the vegetative stage, 1551 operational taxonomic units (OTUs) were detected, while less than half that number (603) were identified in the reproductive stage. The higher bacterial richness observed in floodwater collected during the vegetative stage may have been favored by the higher concentration of nutrients, such as potassium, due to rhizodeposition and fertilizer application. Eighteen bacterial phyla were identified in both samples. Both communities were dominated by Gammaproteobacteria. In the vegetative stage, Alphaproteobacteria and Betaproteobacteria were more abundant and, in contrast, Bacilli and Clostridia were the more dominant classes in the reproductive stage. The major bacterial taxa identified have been previously identified as important colonizers of rice fields. The richness and composition of bacterial communities over cultivation time may contribute to the sustainability of the crop.

Rhizosphere soil microorganism populations and community structures of different watermelon cultivars with differing resistance to Fusarium oxysporum f. sp. niveum

2011 ◽  
Vol 57 (5) ◽  
pp. 355-365 ◽  
Author(s):  
Meijun An ◽  
Xingang Zhou ◽  
Fengzhi Wu ◽  
Yafei Ma ◽  
Ping Yang
Keyword(s):  
Microbial Community ◽  
Fusarium Oxysporum ◽  
Rhizosphere Soil ◽  
Crop Productivity ◽  
Sequencing Analysis ◽  
Culturable Bacteria ◽  
Susceptible Cultivar ◽  
Community Structures ◽  
Opposite Pattern ◽  
Soil Microbial Community Structure

Fusarium wilt is an increasingly serious disease of watermelon that reduces crop productivity. Changes in microorganism populations and bacterial and fungal community structures in rhizosphere soil of watermelon cultivars resistant or susceptible to Fusarium oxysporum f. sp. niveum were investigated using a plate culture method and PCR–DGGE analysis. Plate culture showed that populations of culturable bacteria and actinomycetes were more abundant in the rhizosphere of the resistant watermelon cultivar than the susceptible cultivar, but the fungi population had the opposite pattern. Populations of Penicillium , Fusarium , and Aspergillus were significantly lower in the resistant cultivar than the susceptible cultivar at the fruiting and uprooting stages (p < 0.05). Pattern matching analysis generated the dendrogram of the DGGE results indicating the relatedness of the different resistant watermelon cultivars and their corresponding rhizosphere microbial communities. Further sequencing analysis of specific bands from DGGE profiles indicated that different groups of bacteria and fungi occurred in the rhizosphere of different watermelon cultivars. Our results demonstrated that plant genotype had a significant impact on soil microbial community structure, and the differences in the rhizosphere microbial community may contribute to the differences in resistance to F. oxysporum f. sp. niveum.

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