scholarly journals Negative short-term salt effects on the soybean–Bradyrhizobium japonicum interaction and partial reversion by calcium addition

2014 ◽  
Vol 41 (1) ◽  
pp. 96 ◽  
Author(s):  
Nacira Muñoz ◽  
Marianela Rodriguez ◽  
German Robert ◽  
Ramiro Lascano

The short-term (2 h) effects of salt stress (50 and 150 mM NaCl) on early events of soybean– Bradyrhizobium japonicum (rhizobia) interaction were analysed, determining the following parameters in root hair with or without calcium addition: deformation, apoplastic superoxide radical production (O2⚫–), root hair death and sodium/potassium ion content. We also analysed whether this short-term salt stress influenced later formation of crown and noncrown nodules, determining the number and weight of nodules. The negative effect of salt stress on these characters was attenuated by the addition of 5 mM CaCl2. We also analysed the expression of pathogenesis-related proteins (PRP) genes PR-1, PR-2, PR-3, and four isoforms of PR-5. The expression of PR-2 increased under saline conditions and decreased in osmotic treatment and saline treatment supplemented with calcium in the presence of the symbiont. The changes in PR-2 expression levels, together with the death of root hairs provide a possible mechanism for the inhibition of infection by the symbiont under salinity, and suggests a possible overlap with responses to plant pathogens.

1988 ◽  
Vol 66 (4) ◽  
pp. 683-686 ◽  
Author(s):  
Jeanne M. L. Selker ◽  
John Imsande ◽  
Eldon H. Newcomb

Early emergent nodules on roots of hydroponically grown soybean plants (Glycine max (L.) Merr.) were sectioned serially to locate the site of infection by Bradyrhizobium japonicum. The plants had been inoculated only after their root systems had produced numerous higher order branches. The hydroponic solutions contained all required nutrients, including either a suboptimal concentration of nitrate (0.5 mM) or an excess of nitrate (4.0 mM). In all six nodules examined, three with suboptimal nitrate and three with excess nitrate, we found a centrally located root hair containing an infection thread. We conclude that mature root systems of soybean grown in aqueous culture can undergo infection through root hairs in the way that is typical of young seedlings grown either in pots of vermiculite or pouches.


2012 ◽  
Vol 11 (11) ◽  
pp. 1140-1155 ◽  
Author(s):  
Tran Hong Nha Nguyen ◽  
Laurent Brechenmacher ◽  
Joshua T. Aldrich ◽  
Therese R. Clauss ◽  
Marina A. Gritsenko ◽  
...  

Root hairs are single hair-forming cells on roots that function to increase root surface area, enhancing water and nutrient uptake. In leguminous plants, root hairs also play a critical role as the site of infection by symbiotic nitrogen fixing rhizobia, leading to the formation of a novel organ, the nodule. The initial steps in the rhizobia-root hair infection process are known to involve specific receptor kinases and subsequent kinase cascades. Here, we characterize the phosphoproteome of the root hairs and the corresponding stripped roots (i.e. roots from which root hairs were removed) during rhizobial colonization and infection to gain insight into the molecular mechanism of root hair cell biology. We chose soybean (Glycine max L.), one of the most important crop plants in the legume family, for this study because of its larger root size, which permits isolation of sufficient root hair material for phosphoproteomic analysis. Phosphopeptides derived from root hairs and stripped roots, mock inoculated or inoculated with the soybean-specific rhizobium Bradyrhizobium japonicum, were labeled with the isobaric tag eight-plex iTRAQ, enriched using Ni-NTA magnetic beads and subjected to nanoRPLC-MS/MS1 analysis using HCD and decision tree guided CID/ETD strategy. A total of 1625 unique phosphopeptides, spanning 1659 nonredundant phosphorylation sites, were detected from 1126 soybean phosphoproteins. Among them, 273 phosphopeptides corresponding to 240 phosphoproteins were found to be significantly regulated (>1.5-fold abundance change) in response to inoculation with B. japonicum. The data reveal unique features of the soybean root hair phosphoproteome, including root hair and stripped root-specific phosphorylation suggesting a complex network of kinase-substrate and phosphatase-substrate interactions in response to rhizobial inoculation.


Author(s):  
K.S. Walters ◽  
R.D. Sjolund ◽  
K.C. Moore

Callose, B-1,3-glucan, a component of cell walls, is associated with phloem sieve plates, plasmodesmata, and other cell wall structures that are formed in response to wounding or infection. Callose reacts with aniline blue to form a fluorescent complex that can be recognized in the light microscope with ultraviolet illumination. We have identified callose in cell wall protuberances that are formed spontaneously in suspension-cultured cells of S. tortuosus and in the tips of root hairs formed in sterile callus cultures of S. tortuosus. Callose deposits in root hairs are restricted to root hair tips which appear to be damaged or deformed, while normal root hair tips lack callose deposits. The callose deposits found in suspension culture cells are restricted to regions where unusual outgrowths or protuberances are formed on the cell surfaces, specifically regions that are the sites of new cell wall formation.Callose formation has been shown to be regulated by intracellular calcium levels.


Homeopathy ◽  
2020 ◽  
Author(s):  
Thais Moraes Ferreira ◽  
Mariana Zandomênico Mangeiro ◽  
Alexandre Macedo Almeida ◽  
Ricardo Moreira Souza

Abstract Background There are relatively few scientific works on the use of homeopathy to manage plant pathogens, particularly nematodes. A handful of studies focused on Meloidogyne spp. parasitizing vegetables have brought contradictory results on nematode control and enhancement of plant tolerance to parasitism. Objective Our goal was to assess the effect of Cina—a well-known anti-nematode ingredient—on Meloidogyne enterolobii parasitizing lettuce. Methods Cina was applied daily on nematode-inoculated plants, from the seedling stage until harvest. We tested an evenly spaced range of Hahnemannian concentrations (c), which were applied though irrigation with a constant dose of the ingredient. Several absolute and relative controls were employed to allow the assessment of the effect of Cina on nematode reproduction and lettuce growth. Results Cina affected growth of non-parasitized plants, both positively and negatively; this effect was modulated by the c applied and the thermal stress suffered by the plants in one of the assays. The effect of Cina on the growth of nematode-parasitized plants was neutral or negative. Cina reduced nematode reproduction by 25–36%. Conclusion Based on the moderate negative effect of Cina on M. enterolobii reproduction, it seems this ingredient may be useful as a complementary strategy for Meloidogyne control. But Cina did not enhance the tolerance of lettuce to Meloidogyne spp.


2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 920.1-921
Author(s):  
N. Stepanenko ◽  
E. Fedorov ◽  
S. Salugina ◽  
S. Feoktistova

Background:Monogenic auto-inflammatory diseases (mAID) are a group of severe chronic multisystemic diseases with recurring episodes of fever and other manifestations that significantly affect the patients’ life quality. Moreover, the hyper expression of pro-inflammatory cytokines (IL1β, etc.) observed in these patients may have a negative effect on the central nervous system.Objectives:to study the state of the cognitive and emotional spheres in children suffering from monogenic auto-inflammatory diseases.Methods:there were examined 22 children at the age of 7 to 17 years old diagnosed with CAPS-9, TRAPS-8, FMF-5. Among them there were 12 boys and 10 girls. The diagnosis in all the patients was confirmed through detection of pathogenic mutations in the NLRP3, TNFRSF1A and MEFV genes. The following methods were used: a clinical conversation; memory diagnostics (learning by heart of 10 words, a pictogram using cues taking into account the patients’ age); attention diagnostics (Schulte tables); thinking diagnostics (establishing a sequence of events, “four is a crwod”, simple analogies, interpretation of proverbs); emotional and communicative fields (the Eight-Color Luscher Test; CMAS (adaptation by A. Prikhozhan); STAI test, a drawing called “an animal that does not exist” and “a house-a tree-a man”).Results:The memory study revealed in all patients with TRAPS and FMF high and medium values of short-term and long-term memory, in patients with CAPS - a low level of short-term auditory-speech memory, information storage and indirect memorization in 1/3 of patients. In 100% of the examined patients with TRAPS, a significant decrease in all processes of attention and distribution of attention. In 1/3 of patients with CAPS, an increased exhaustion of attention was registered and in 11% - a decrease in its stability. In patients with FMF, attention disorders were not detected. In 44% of patients with CAPS, a decrease in the level of generalization and difficulties in establishing causal relationships were registered. In 25% of patients with TRAPS a decrease in the level of generalization, in 12.5%- difficulties in establishing cause-effect relationships, inertia of thinking in 37.5%. In 60% of patients with FMF: a decrease in the level of generalization, in 80%: difficulties in establishing cause-effect relationships, inertia of thinking in 20%. In the emotional sphere, patients with CAPS, TRAPS, and FMF demonstrated signs of aggression (11.1%, 20% and 20% of patients, respectively), communicative disorders (77.8% -80% - 80%), and reduced social adaptation (55.5% - 80% - 80%), a tendency to form neurotic fears (22% - 40% - 40%). A high level of personal anxiety was noted in 1/3 of patients with CAPS and 40% of patients with FMF.Conclusion:various psychological disorders in the cognitive and emotional fields were noted in the majority of the examined patients with monogenic auto-inflammatory diseases. In patients with TRAPS, attention processes are most significantly affected; in patients with CAPS, memory is more often affected. In patients with FMF, disorders in thinking processes are revealed more often. In the emotional sphere, most patients with all the three forms of AID note communicative disorders and social adaptation.Disclosure of Interests:None declared


2021 ◽  
pp. 109634802110191
Author(s):  
Jungtae Soh ◽  
Kwanglim Seo

Much scholarly attention has been paid to Airbnb’s influence on the hotel industry. However, extant studies have limitations because they consider only Airbnb while overlooking various other short-term vacation rental players that can also affect performance of hotels. To address this research gap, this study aims to provide a broader understanding of the impacts of short-term vacation rentals by analyzing data obtained from various vacation rental platforms. This study shows that while increase in short-term vacation rentals has an overall negative effect on hotel performance, the economic effect is more significant in the low-end market than in the high-end market. Our findings further reveal that the negative effect is reduced when there is a large price difference between short-term vacation rentals and hotels. By comprehensively examining multiple sources of data on hotels and vacation rentals, this study brings alternative perspectives to the attention of researchers for further investigation of vacation rentals.


Plants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 150 ◽  
Author(s):  
Katarzyna Retzer ◽  
Wolfram Weckwerth

Plant growth and productivity are orchestrated by a network of signaling cascades involved in balancing responses to perceived environmental changes with resource availability. Vascular plants are divided into the shoot, an aboveground organ where sugar is synthesized, and the underground located root. Continuous growth requires the generation of energy in the form of carbohydrates in the leaves upon photosynthesis and uptake of nutrients and water through root hairs. Root hair outgrowth depends on the overall condition of the plant and its energy level must be high enough to maintain root growth. TARGET OF RAPAMYCIN (TOR)-mediated signaling cascades serve as a hub to evaluate which resources are needed to respond to external stimuli and which are available to maintain proper plant adaptation. Root hair growth further requires appropriate distribution of the phytohormone auxin, which primes root hair cell fate and triggers root hair elongation. Auxin is transported in an active, directed manner by a plasma membrane located carrier. The auxin efflux carrier PIN-FORMED 2 is necessary to transport auxin to root hair cells, followed by subcellular rearrangements involved in root hair outgrowth. This review presents an overview of events upstream and downstream of PIN2 action, which are involved in root hair growth control.


2018 ◽  
Vol 20 (1) ◽  
pp. 93
Author(s):  
Jin Wang ◽  
Feiyi Huang ◽  
Xiong You ◽  
Xilin Hou

In plants, heptahelical proteins (HHPs) have been shown to respond to a variety of abiotic stresses, including cold stress. Up to the present, the regulation mechanism of HHP5 under low temperature stress remains unclear. In this study, BcHHP5 was isolated from Pak-choi (Brassica rapa ssp. chinensis cv. Suzhouqing). Sequence analysis and phylogenetic analysis indicated that BcHHP5 in Pak-choi is similar to AtHHP5 in Arabidopsis thaliana. Structure analysis showed that the structure of the BcHHP5 protein is relatively stable and highly conservative. Subcellular localization indicated that BcHHP5 was localized on the cell membrane and nuclear membrane. Furthermore, real-time quantitative polymerase chain reaction (RT-qPCR) analysis showed that BcHHP5 was induced to express by cold and other abiotic stresses. In Pak-choi, BcHHP5-silenced assay, inhibiting the action of endogenous BcHHP5, indicated that BcHHP5-silenced might have a negative effect on cold tolerance, which was further confirmed. All of these results indicate that BcHHP5 might play a role in abiotic response. This work can serve as a reference for the functional analysis of other cold-related proteins from Pak-choi in the future.


1986 ◽  
Vol 64 (10) ◽  
pp. 2216-2226 ◽  
Author(s):  
Yves Prin ◽  
Mireille Rougier

The aim of the present study was to investigate the Alnus root surface using seedlings grown axenically. This study has focused on root zones where infection by the symbiotic actinomycete Frankia takes place. The zones examined extend from the root cap to the emerging root hair zone. The root cap ensheaths the Alnus root apex and extends over the root surface as a layer of highly flattened cells closely appressed to the root epidermal cell wall. These cells contain phenolic compounds as demonstrated by various histochemical tests. They are externally bordered by a thin cell wall coated by a thin mucilage layer. The root cap is ruptured when underlying epidermal cells elongate, and cell remnants are still found in the emerging root hair zone. Young emerging root hairs are bordered externally by a cell wall covered by a thin mucilage layer which reacts positively to the tests used for the detection of polysaccharides, glycoproteins, and anionic sites. The characteristics of the Alnus root surface and the biological function of mucilage and phenols present at the root surface are discussed in relation to the infection process.


Resting spore germination and the root hair stages of the life history of Plasmodiophora brassicae were studied in stained preparations of infected Brassica rapa seedling roots. Naked protoplasts, usually possessing two unequal flagella, were released from resting spores through a small circular pore. They penetrated the root hairs of B. rapa and there developed into plasmodia which, after becoming multinucleate, cleaved to form zoosporangia con­taining incipient zoospores. Biflagellate zoospores were released from root hair zoosporangia and fused in pairs, although karyogamy did not occur. The resulting binucleate zoospores infected the cortical dells of B. rapa to form binucleate plasmodia, the earliest stages of the secondary phase of the life history. These findings are discussed in relation to previous studies on the life history of P. brassicae in Brassica plants and in Brassica tissue cultures, and a new complete life history, including nuclear fusion in the secondary plasmodium, is suggested for the organism.


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