scholarly journals Isolates of the Nematophagous Fungus Pochonia chlamydosporia Are Endophytic in Banana Roots and Promote Plant Growth

Agronomy ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1299
Author(s):  
Cristina Mingot-Ureta ◽  
Federico Lopez-Moya ◽  
Luis Vicente Lopez-Llorca
Keyword(s):  
Fluorescent Protein ◽  
Root Hairs ◽  
Root Surface ◽  
Nematophagous Fungus ◽  
Leaf Length ◽  
Post Inoculation ◽  
Root Cells ◽  
Pochonia Chlamydosporia ◽  
Green Fluorescent ◽  
Spore Inoculation

The biocontrol fungus Pochonia chlamydosporia colonizes banana roots endophytically. Root hairs and root surface were colonized by a stable GFP (green fluorescent protein) transformant of the fungus. Hyphal penetration in root cells was also observed. Spores of P. chlamydosporia 123, significantly increase root and leaf length and weight in banana plantlets (Musa acuminata cv. ‘Dwarf Cavendish’) in growth chamber experiments 30 days post-inoculation. In greenhouse 8-L pot experiments, P. chlamydosporia 123 spore inoculation significantly increases root, corm and leaf length, and leaf weight in banana plants (75 days post-inoculation). Spore inoculation of P. chlamydosporia strains from diverse origin (Pc21, Pc123, Pc399, and Pccat), significantly increase root, corm and leaf length and weight in banana plantlets. Pc21 from Italy was the best colonizer of banana roots. Consequently, this strain significantly increases banana root and leaf length most. Root colonization by P. chlamydosporia was also detected using cultural techniques and qPCR.

scholarly journals Worldwide strains of the nematophagous fungus Pochonia chlamydosporia are endophytic in banana roots and promote plant growth

2020 ◽  
Author(s):  
Cristina Mingot-Ureta ◽  
Federico Lopez-Moya ◽  
Luis Vicente Lopez-Llorca
Keyword(s):  
Root Colonization ◽  
Root Hairs ◽  
Root Surface ◽  
Nematophagous Fungus ◽  
Leaf Length ◽  
Post Inoculation ◽  
Root Cells ◽  
Pochonia Chlamydosporia ◽  
Promote Plant Growth ◽  
Spore Inoculation

SUMMARYThe biocontrol fungus, Pochonia chlamydosporia, colonizes endophytically banana roots. Root hairs and root surface were found colonize by the fungus using a stable GFP transformant. Hyphal penetration of root cells was also observed. Spores of P. chlamydosporia 123, significantly increase root and leaf length and weight in banana plantlets (Musa acuminata cv. ‘Dwarf Cavendish’) in growth chamber experiments 30 days post-inoculation (dpi). In greenhouse 8L pot experiments, P. chlamydosporia 123 spore inoculation significantly increases leaf and root length and leaf weight in banana plants (75 dpi). Spore inoculation of P. chlamydosporia strains from worldwide origin (Pc21 Italy, Pc123 Spain, Pc399 China, and Pccat Cuba), significantly increases root, corm and leaf length and weight in banana plantlets. Pc21 was the best colonizer of banana roots. Consequently, this strain significantly increases most banana root and leaf length. Root colonization by P. chlamydosporia was also detected using cultural techniques and qPCR.

scholarly journals Nodulation of Aeschynomene afraspera and A. indica by Photosynthetic Bradyrhizobium Sp. Strain ORS285: The Nod-Dependent Versus the Nod-Independent Symbiotic Interaction

2011 ◽  
Vol 24 (11) ◽  
pp. 1359-1371 ◽  
Author(s):  
Katia Bonaldi ◽  
Daniel Gargani ◽  
Yves Prin ◽  
Joel Fardoux ◽  
Djamel Gully ◽  
...  
Keyword(s):  
Fluorescent Protein ◽  
Lateral Roots ◽  
Root Hairs ◽  
Infection Process ◽  
Cortical Cells ◽  
Symbiotic Interaction ◽  
Root Cortex ◽  
Bradyrhizobium Sp ◽  
Infected Cells ◽  
Green Fluorescent

Here, we present a comparative analysis of the nodulation processes of Aeschynomene afraspera and A. indica that differ in their requirement for Nod factors (NF) to initiate symbiosis with photosynthetic bradyrhizobia. The infection process and nodule organogenesis was examined using the green fluorescent protein–labeled Bradyrhizobium sp. strain ORS285 able to nodulate both species. In A. indica, when the NF-independent strategy is used, bacteria penetrated the root intercellularly between axillary root hairs and invaded the subepidermal cortical cells by invagination of the host cell wall. Whereas the first infected cortical cells collapsed, the infected ones immediately beneath kept their integrity and divided repeatedly to form the nodule. In A. afraspera, when the NF-dependent strategy is used, bacteria entered the plant through epidermal fissures generated by the emergence of lateral roots and spread deeper intercellularly in the root cortex, infecting some cortical cells during their progression. Whereas the infected cells of the lower cortical layers divided rapidly to form the nodule, the infected cells of the upper layers gave rise to an outgrowth in which the bacteria remained enclosed in large tubular structures. Together, two distinct modes of infection and nodule organogenesis coexist in Aeschynomene legumes, each displaying original features.

scholarly journals Granular Size Effect of Clinoptilolite on Maize Seedlings Growth

2010 ◽  
Vol 4 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Alessandra Trinchera ◽  
Carlos Mario Rivera ◽  
Simona Rinaldi ◽  
Anna Salerno ◽  
Elvira Rea ◽  
...  
Keyword(s):  
Organic Fertilizer ◽  
Root Hairs ◽  
Microscopic Analysis ◽  
Root Surface ◽  
Limited Data ◽  
Root Cells ◽  
Enhanced Production ◽  
Growing Medium ◽  
Isolated Roots ◽  
Inert Substrate

Clinoptilolite has been successfully used in growing media for containerized horticultural and floricultural production. However, limited data exist on the effects and interaction between particle size and organic nutrient enrichment of the clinoptilolite. One granular (1-3 mm) and micronized (< 30 µm) clinoptilolite was added to quartz sand, an inert growing substrate, at two doses (0.1% and 3% v/v), without or with addition of wine vinasse as nutrient source at four concentrations (0 mgF×Lsubst-1, 10 mgF×Lsubst-1, 100 mgF×Lsubst-1 and 1000 mgF×Lsubst-1) to evaluate their effect on root growth for five days or the appearance of the second true leaf. Root mucigel was produced in zones where clinoptilolite particles adhered to the root surface. Microscopic analysis of isolated roots showed the increase of secondary roots and the proliferation of root hairs in maize treated with both micronized and granular clinoptilolite, with the contemporary production of root mucigel in zones where zeolite particles adhered to the root surface. It is hypothesized that the enhanced production of mucigel by root cells can favour not only the penetration of roots into the inert substrate, but also the solubilization of organic matter and nutrient availability, in particular when micronized clinoptilolite was present in the growing medium. Therefore, micronized clinoptilolite behaved as a sort of a “physical stimulant” for roots during seedlings, promoting, as a consequence, maize shoot development. Effectively, the highest increase in shoot growth was observed at the highest dose (3% v/v) of micronized zeolite, with the optimal rate of organic fertilizer (100 mgF×Lsubst-1).

Presence and persistence of wastewater pathogen Escherichia coli O157:H7 in hydroponic reactors of treatment wetland species

2015 ◽  
Vol 72 (1) ◽  
pp. 135-140 ◽  
Author(s):  
R. J. VanKempen-Fryling ◽  
O. R. Stein ◽  
A. K. Camper
Keyword(s):  
Escherichia Coli ◽  
Fluorescent Protein ◽  
Single Cells ◽  
Order Reduction ◽  
The United States ◽  
Root Surface ◽  
Post Inoculation ◽  
Treatment Wetland ◽  
E Coli ◽  
Abiotic Control

Abstract Treatment wetlands (TWs) efficiently remove many pollutants including a several log order reduction of pathogens from influent to effluent; however, there is evidence to suggest that pathogen cells are sequestered in a subsurface wetland and may remain viable months after inoculation. Escherichia coli is a common pathogen in domestic and agricultural wastewater and the O157:H7 strain causes most environmental outbreaks in the United States. To assess attachment of E. coli to the TW rhizosphere, direct measurements of E. coli levels were taken. Experiments were performed in chemostats containing either Teflon nylon as an abiotic control or roots of Carex utriculata or Schoenoplectus acutus. Flow of simulated wastewater through the chemostat was set to maintain a 2 hour residence time. The influent was inoculated with E. coli O157:H7 containing DsRed fluorescent protein. Root samples were excised and analyzed via epifluorescent microscopy. E. coli O157:H7 was detected on the root surface at 2 hours after inoculation, and were visible as single cells. Microcolonies began forming at 24 hours post-inoculation and were detected for up to 1 week post-inoculation. Image analysis determined that the number of microcolonies with &gt;100 cells increased 1 week post-inoculation, confirming that E. coli O157:H7 is capable of growth within biofilms surrounding wetland plant roots.

scholarly journals Transformed Hairy Roots of Arachis hypogea: A Tool for Studying Root Nodule Symbiosis in a Non–Infection Thread Legume of the Aeschynomeneae Tribe

2009 ◽  
Vol 22 (2) ◽  
pp. 132-142 ◽  
Author(s):  
Senjuti Sinharoy ◽  
Sudip Saha ◽  
Susanta Roy Chaudhury ◽  
Maitrayee DasGupta
Keyword(s):  
Hairy Roots ◽  
Fluorescent Protein ◽  
Root Hairs ◽  
Infection Thread ◽  
Natural Soil ◽  
35S Promoter ◽  
Wild Type ◽  
Cortical Cells ◽  
Arachis Hypogea ◽  
Green Fluorescent

Arachis hypogea is a non–“infection thread” (IT) legume where rhizobial entry or dissemination in the nodules never involves IT. Rhizobia invade through epidermal “cracks” and directly access the cortical cells to develop the characteristic aeschynomenoid nodules. For investigating these nonclassical nodulation features in Arachis spp., we developed an efficient procedure for Agrobacterium rhizogenes R1000-mediated transformation of this plant. In this study, we optimized the induction of hairy roots and nodulation of composite Arachis hypogea plants in the presence of Bradyrhizobium sp. (Arachis) strain NC92. 35S promoter-driven green fluorescent protein and β-glucuronidase expression indicated transformation frequency to be above 80%. The transformed roots had the characteristic rosette-type root hairs and had normal level of expression of symbiosis-related genes SymRK and CCaMK. The transgenic nodules resembled the wild-type nodules with an exception of 2 to 3%, where they structurally deviated from the wild-type nodules to form nodular roots. A 16S rRNA profile of an infected-zone metagenome indicated that identical populations of bradyrhizobia invaded both composite wild-type plants grown in natural soil. Our results demonstrate that Arachis hairy root is an attractive system for undertaking investigations of the nonclassical features associated with its nitrogen-fixing symbiotic interactions.

Strain-Specific Differences in the Attachment of Listeria monocytogenes to Alfalfa Sprouts

2004 ◽  
Vol 67 (11) ◽  
pp. 2488-2495 ◽  
Author(s):  
LISA GORSKI ◽  
JEFFREY D. PALUMBO ◽  
KIMANH D. NGUYEN
Keyword(s):  
Green Fluorescent Protein ◽  
Listeria Monocytogenes ◽  
Microscopic Examination ◽  
Irrigation Water ◽  
Fluorescent Protein ◽  
Fresh Produce ◽  
Root Hairs ◽  
Human Pathogen ◽  
Alfalfa Sprouts ◽  
Green Fluorescent

Contamination of fresh produce with Listeria monocytogenes has resulted in outbreaks of systemic listeriosis and febrile gastroenteritis. Recalls of alfalfa sprouts have occurred due to contamination with L. monocytogenes. Alfalfa sprouts were used as a preharvest model to study the interaction with this human pathogen. Seventeen strains were assessed for their capacity to colonize alfalfa sprouts, and strain-specific differences (not related to source, serotype, or lineage) were revealed when the sprout irrigation water was changed daily. Two of the strains colonized and attached to the sprouts very well, reaching levels of more than 5 log CFU per sprout. The remaining strains varied in their final levels on sprouts between less than 1 to 4.7 log CFU per sprout. All of the L. monocytogenes strains grew to equivalent levels on the sprouts when the irrigation water was not changed, suggesting the differences observed with regular changing of the water resulted from differences in attachment. Further analysis of the best colonizing strains indicated that only between 0.3 and 1 log CFU per sprout could be removed by additional washing of the sprout, and the presence of normal sprout bacteria did not compete with the L. monocytogenes strains on the sprouts. The poorest colonizing strain was able to grow in the irrigation water during the experiment but could not attach to the sprouts. Microscopic examination of the sprouts with L. monocytogenes expressing the green fluorescent protein indicated that L. monocytogenes was associated with the root hairs of the sprouting alfalfa, with few to no cells visible elsewhere on the sprout.

scholarly journals Building a hair: tip growth in Arabidopsis thaliana root hairs

2002 ◽  
Vol 357 (1422) ◽  
pp. 815-821 ◽  
Author(s):  
Rachel J. Carol ◽  
Liam Dolan
Keyword(s):  
Arabidopsis Thaliana ◽  
Reverse Genetics ◽  
Tip Growth ◽  
Fluorescent Protein ◽  
Calcium Influx ◽  
Root Hairs ◽  
New Information ◽  
Active Calcium ◽  
Green Fluorescent

The Arabidopsis thaliana root hair is used as a model for studying tip growth in plants. We review recent advances, made using physiological and genetic approaches, which give rise to different, yet compatible, current views of the establishment and maintenance of tip growth in epidermal cells. For example, an active calcium influx channel localized at the tip of Arabidopsis root hairs has been identified by patch–clamp measurements. Actin has been visualized in vivo in Arabidopsis root hairs by using a green–fluorescent–protein–talin reporter and shown to form a dense mesh in the apex of the growing tip. The kojak gene, which encodes a protein similar to the catalytic subunit of cellulose synthase, is needed in the first stages of hair growth. A role for LRX1 , a leucine–rich repeat extensin, in determining the morphology of the cell wall of root hairs has been established using reverse genetics. The new information can be integrated into a general and more advanced view of how these specialized plant cells grow.

scholarly journals Succinoglycan Is Required for Initiation and Elongation of Infection Threads during Nodulation of Alfalfa byRhizobium meliloti

1998 ◽  
Vol 180 (19) ◽  
pp. 5183-5191 ◽  
Author(s):  
Hai-Ping Cheng ◽  
Graham C. Walker
Keyword(s):  
Molecular Weight ◽  
Fluorescent Protein ◽  
Rhizobium Meliloti ◽  
Root Hairs ◽  
Invasion Process ◽  
Nitrogen Fixing ◽  
Excess Production ◽  
Infection Threads ◽  
Reduced Rate ◽  
Green Fluorescent

ABSTRACT Rhizobium meliloti Rm1021 must be able to synthesize succinoglycan in order to invade successfully the nodules which it elicits on alfalfa and to establish an effective nitrogen-fixing symbiosis. Using R. meliloti cells that express green fluorescent protein (GFP), we have examined the nature of the symbiotic deficiency of exo mutants that are defective or altered in succinoglycan production. Our observations indicate that anexoY mutant, which does not produce succinoglycan, is symbiotically defective because it cannot initiate the formation of infection threads. An exoZ mutant, which produces succinoglycan without the acetyl modification, forms nitrogen-fixing nodules on plants, but it exhibits a reduced efficiency in the initiation and elongation of infection threads. An exoHmutant, which produces symbiotically nonfunctional high-molecular-weight succinoglycan that lacks the succinyl modification, cannot form extended infection threads. Infection threads initiate at a reduced rate and then abort before they reach the base of the root hairs. Overproduction of succinoglycan by theexoS96::Tn5 mutant does not reduce the efficiency of infection thread initiation and elongation, but it does significantly reduce the ability of this mutant to colonize the curled root hairs, which is the first step of the invasion process. TheexoR95::Tn5 mutant, which overproduces succinoglycan to an even greater extent than theexoS96::Tn5 mutant, has completely lost its ability to colonize the curled root hairs. These new observations lead us to propose that succinoglycan is required for both the initiation and elongation of infection threads during nodule invasion and that excess production of succinoglycan interferes with the ability of the rhizobia to colonize curled root hairs.

scholarly journals A Core35S Promoter of Cauliflower Mosaic Virus Drives More Efficient Replication of Turnip Crinkle Virus

Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1700
Author(s):  
Md Emran Ali ◽  
Sumyya Waliullah
Keyword(s):  
Virus Replication ◽  
Fluorescent Protein ◽  
Rna Virus ◽  
Cauliflower Mosaic Virus ◽  
35S Promoter ◽  
Cdna Clones ◽  
Post Inoculation ◽  
Turnip Crinkle Virus ◽  
Green Fluorescent ◽  
High Level

The 35S promoter with a duplicated enhancer (frequently referred to as 2X35S) is a strong dicotyledonous plant-specific promoter commonly used in generating transgenic plants to enable high-level expression of genes of interest. It is also used to drive the initiation of RNA virus replication from viral cDNA, with the consensus understanding that high levels of viral RNA production powered by 2X35S permit a more efficient initiation of virus replication. Here, we showed that the exact opposite is true. We found that, compared to the Core35S promoter, the 2X35S promoter-driven initiation of turnip crinkle virus (TCV) infection was delayed by at least 24 h. We first compared three versions of 35S promoter, namely 2X35S, 1X35S, and Core35S, for their ability to power the expression of a non-replicating green fluorescent protein (GFP) gene, and confirmed that 2X35S and Core35S correlated with the highest and lowest GFP expression, respectively. However, when inserted upstream of TCV cDNA, 2X35S-driven replication was not detected until 72 h post-inoculation (72 hpi) in inoculated leaves. By contrast, Core35S-driven replication was detected earlier at 48 hpi. A similar delay was also observed in systemically infected leaves (six versus four days post-inoculation). Combining our results, we hypothesized that the stronger 2X35S promoter might enable a higher accumulation of a TCV protein that became a repressor of TCV replication at higher cellular concentration. Extending from these results, we propose that the Core35S (or mini35S) promoter is likely a better choice for generating infectious cDNA clones of TCV.

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