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

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.

Agronomy ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1299
Author(s):  
Cristina Mingot-Ureta ◽  
Federico Lopez-Moya ◽  
Luis Vicente Lopez-Llorca

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.


2010 ◽  
Vol 4 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Alessandra Trinchera ◽  
Carlos Mario Rivera ◽  
Simona Rinaldi ◽  
Anna Salerno ◽  
Elvira Rea ◽  
...  

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).


2016 ◽  
Vol 213 (1) ◽  
pp. 351-364 ◽  
Author(s):  
Ernesto A. Zavala-Gonzalez ◽  
Encarnación Rodríguez-Cazorla ◽  
Nuria Escudero ◽  
Almudena Aranda-Martinez ◽  
Antonio Martínez-Laborda ◽  
...  

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.


Author(s):  
Sangram Sinha ◽  

The Rhizosphere is the small zone surrounding plants' root surface is now considered as hot spot for microbial diversity and pivotal for plant-microbe interaction. The plant-microbe interaction is very vital for plant growth, productivity and stress tolerance. The present study attempted to explore the culturable microbial diversity in the tomato Rhizosphere from agricultural fields of Haripal block of West Bengal. The study found that the Rhizosphere is rich in gram-positive rods, and further biochemical characterisation predicted Bacillus cereus as the signature genus consisting of 26% of the total bacteria characterised in this study. Pearson’s correlation coefficient of different important adaptive characters of the bacterial population revealed strong correlations between salt tolerance, exo-polysaccharide (EPS) production, acid tolerance and phosphate solubilizing activity. These interactions may be crucial for Rhizosphere colonisation and overcoming hostile environment like salinity, drought, soil acidity and ultimately promote plant growth under diverse environmental stress.


1990 ◽  
Vol 68 (3) ◽  
pp. 579-593 ◽  
Author(s):  
H. B. Massicotte ◽  
R. L. Peterson ◽  
C. A. Ackerley ◽  
L. H. Melville

The ontogeny and ultrastructure of ectomycorrhizae synthesized between Betula alleghaniensis (yellow birch) and Pisolithus tinctorius, a broad host range fungus, were studied to determine the structural modifications in both symbionts during ectomycorrhiza establishment. A number of stages, including initial contact of hyphae with the root surface, early mantle formation, and mature mantle formation, were distinguished. Interactions between hyphae and root hairs were frequent. As a paraepidermal Hartig net developed, root epidermal cells elongated in a radial direction, but wall ingrowths were not formed. Repeated branching of Hartig net hyphae resulted in extensive fine branches and the compartmentalization of hyphal cytoplasm. Nuclei and elongated mitochondria were frequently located in the narrow cytoplasmic compartments, and [Formula: see text] thickenings developed along walls of cortical cells in primary roots.


2002 ◽  
Vol 29 (5) ◽  
pp. 595 ◽  
Author(s):  
Sergey Shabala ◽  
Andrew Knowles

Oscillatory patterns in H+, K+, Ca2+ and Cl- uptake were observed at different regions of the root surface, including root hairs, using a non-invasive ion flux measuring technique (the MIFE™ technique). To our knowledge, this is the first report of ultradian oscillations in nutrient acquisition in the mature root zone. Oscillations of the largest magnitude were usually measured in the elongation region, 2–4 mm from the root apex. There were usually at least two oscillatory components present for each ion measured: fast, with periods of several minutes; and slow, with periods of 50–80 min. Even within the same functional zone, the periods of ion flux oscillations were significantly different, suggesting that they are driven by some internal mechanisms located in each cell rather than originating from one ‘central clock pacemaker’. There were also significant changes in the oscillatory characteristics (both periods and amplitudes) of fluxes from a single small cluster of cells over time. Analysis of phase shifts between oscillations in different ions suggested that rhythmic activity of a plasma membrane H+-pump may be central to observed rhythmic nutrient acquisition by plant roots. We discuss the possible adaptive significance of such an oscillatory strategy for root nutrient acquisition.


2005 ◽  
Vol 95 (8) ◽  
pp. 890-893 ◽  
Author(s):  
Kening Wang ◽  
Robert D. Riggs ◽  
Devany Crippen

The reniform nematode, Rotylenchulus reniformis, is a serious threat to cotton (Gossypium hirsutum) production in the United States, causing an annual loss of about $80 million. The objective of this study was to isolate fungi from eggs of R. reniformis and select potential biocontrol agents for R. reniformis on cotton. We focused on the fungus Pochonia chlamydosporia because it suppresses root-knot and cyst nematodes and because preliminary data indicated that it was present in Arkansas cotton fields. Soil samples were collected from six cotton fields in Jefferson County, Arkansas. A total of 117 isolates of the nematophagous fungus P. chlamydosporia were obtained. In an in vitro test, 105 of the 117 isolates parasitized fewer than 15% of R. reniformis eggs, but 12 isolates parasitized between 16 and 35% of the eggs. These 12 isolates produced from 6.8 × 104 to 6.9 × 105 chlamydospores per gram of medium in vitro, and chlamydospore production was similar on rice grain and corn grain media. In two greenhouse experiments, a single application of isolate 37 (5,000 chlamydospores per gram of soil) significantly reduced the numbers of R. reniformis on cotton roots and in soil. The three isolates (37, 26, and 14) that parasitized the most eggs in vitro were also the most effective in suppressing numbers of R. reniformis and in increasing cotton growth in the greenhouse.


2020 ◽  
Author(s):  
Patrick Duddek ◽  
Mutez Ahmed ◽  
Mohsen Zarebanadkouki ◽  
Nicolai Koebernick ◽  
Goran Lovric ◽  
...  

&lt;p&gt;Although 40% of total terrestrial precipitation transits the rhizosphere, there is still substantive lack of understanding of the rhizosphere biophysical properties and their impact on root water uptake. Our hypothesis is that roots are capable of altering the biophysical properties of the rhizosphere and hereby facilitating root water uptake. In particular, we expect that root hairs maintain the hydraulic contact between roots and soil at low water potentials.&amp;#160;We have recently shown that root hairs facilitate root water uptake in dry soils at high transpiration rates. Our explanation was that root hairs extend the effective root radius decreasing the flow velocity at the root surface and hence the drop in matric potential across the rhizosphere.&lt;/p&gt;&lt;p&gt;To test this hypothesis, we used synchrotron X-ray CT to image the distribution of root hairs in soils. The experiments were conducted with two maize genotypes (with and without root hairs) grown in two soil textures (loam vs sand). Segmenting the different domains within the high-resolution images enabled us to quantify the contact area of the root surface and root hairs with the soil matrix at different water potentials. Furthermore, we calculated the geodesic distance between the root and the soil matrix as a proxy of the accessibility of water to the root.&lt;/p&gt;&lt;p&gt;The results show that root hairs increase the total root surface by approx. 30% and the contact area with the soil matrix by approx. 40%. Furthermore, the average distance from the soil to the root surface decreases by approx. 40% due to hairs, which is the effect of root hairs preferentially growing through macropores. In summary, root hairs not only increase the root surface and the root-soil contact area, but also bridge the air-filled pores between the root epidermis and the soil matrix, thus facilitating the extraction of water. &amp;#160;On top of that, the segmented CT images are also the basis for image-based models aiming at quantifying root water uptake and the effect of root hairs.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;References&lt;/p&gt;&lt;ul&gt;&lt;li&gt;(1) Koebernick N, Daly KR, Keyes SD, et al. 2019. Imaging microstructure of the barley rhizosphere: particle packing and root hair influences. New Phytologist 221, 1878&amp;#8211;1889.&lt;/li&gt; &lt;li&gt;(2) Carminati A, Benard P, Ahmed MA, Zarebanadkouki M. 2017. Liquid bridges at the root-soil interface. Plant and Soil 417, 1&amp;#8211;15.&lt;/li&gt; &lt;/ul&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;


1965 ◽  
Vol 11 (3) ◽  
pp. 483-489 ◽  
Author(s):  
E. A. Peterson ◽  
J. W. Rouatt ◽  
H. Katznelson

The influence of soil moisture on the microbial population of rhizosphere soil and of the root surface (rhizoplane) of wheat was studied under controlled conditions. Fertile soil adjusted to 30%, 60%, and 90% of its moisture-holding capacity was used. Bacterial counts and numbers of specific "physiological groups" of bacteria all increased in the rhizosphere and the rhizoplane as soil moisture decreased. Taxonomic studies of the bacteria isolated from the rhizoplane showed a marked preponderance of species of Pseudomonas under conditions of low and intermediate soil moisture content. On the other hand species of Arthrobacter, Bacillus, and Cytophaga dominated the population at high soil moisture. Although the distribution of fungi on the roots was very similar for the low and intermediate moisture levels, there was some restriction of colonization at the high level. Species of Mortierella, Rhizopus, Chaetomium, Curvularia, and Helminthosporium were not represented among isolates from roots at high soil moisture and the relative incidence of species of Fusarium and Phoma decreased. However, high soil moisture favored root colonization by species of Rhizoctonia and sterile dark fungi.


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