scholarly journals NPR1 is required for root colonization and the establishment of a mutualistic symbiosis between the beneficial bacterium Rhizobium radiobacter and barley

Author(s):  
Neelendra Kumar ◽  
Matteo Galli ◽  
D'Maris Dempsey ◽  
Jafargholi Imani ◽  
Anna Moebus ◽  
...  
2001 ◽  
Vol 15 (2) ◽  
pp. 155-165 ◽  
Author(s):  
Gladstone Alves da Silva ◽  
Bartolomeu Acioli dos Santos ◽  
Marccus Vinícius Alves ◽  
Leonor Costa Maia

Mycorrhiza are a mutualistic symbiosis between fungi and plant roots, the main benefit to the plant being increased nutrient uptake. The arbuscular is the most important kind of mycorrhiza for agriculture and it is widespread in occurrence and distribution in most ecosystems. The aim of this work was to study the mycorrhizal status of the species of Commelinidae that occur in the State of Pernambuco. Plant roots, collected in ten municipalities, were washed, cleared in KOH, stained with Trypan blue in lactoglycerol and observed under a light microscope in order to assess presence and identification of the mycorrhizal type. Percentage of root colonization was evaluated by the gridline intersect method. Forty specimens representing 30 species were observed. From these specimens, 70% were colonized by arbuscular mycorrhizal fungi (AMF). In one family (Typhaceae), mycorrhizal structures were not observed, in two of them (Eriocaulaceae and Juncaceae) all specimens showed the association, and three families (Commelinaceae, Cyperaceae and Poaceae) presented specimens with or without AMF. In some of the roots, other fungi were observed together with the AMF. The results indicate that AMF are widely distributed among species of Commelinidae in Pernambuco, being probably important for their establishment in the areas visited.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 501d-501
Author(s):  
Jonathan N. Egilla ◽  
Fred T. Davies

Six endomycorrhiza isolates from the Sonoran Desert of Mexico [Desert-14(18)1, 15(9)1, 15(15)1, Palo Fierro, Sonoran, and G. geosporum] were evaluated with a pure isolate of Glomus intraradices for their effect on the growth and gas exchange of Hibiscus rosa-sinensis L. cv. Leprechaun under low phosphorus fertility (11 mg P/L). Rooted cuttings of Hibiscus plants were inoculated with the seven mycorrhiza isolates and grown for 122 days. Gas exchange measurements were made on days 26, 88, and 122 after inoculation, and plants were harvested on day 123 for growth analysis. Plants inoculated with the seven isolates had 70% to 80% root colonization at harvest. Plants inoculated with G. intraradices had significantly higher leaf, shoot and root dry matter (DM), leaf DM/area (P ≤ 0.05) than those inoculated with any of the six isolates, and greater leaf area (LA) than Desert-15(9)1 and 15(15)1. Uninoculated plants had significantly lower leaf, shoot, root DM, leaf DM/area and LA (P ≤ 0.05) than the inoculated plants. There were no differences among the seven isolates in any of the gas exchange parameters measured [photosynthesis (A) stomatal conductance (gs), the ratio of intercellular to external CO2 (ci/ca), A to transpiration (E) ratio (A/E)]. The relationship between inoculated and uninoculated plants in these gas exchange parameters were variable on day 122 after inoculation.


2006 ◽  
Vol 47 (7) ◽  
pp. 807-817 ◽  
Author(s):  
Daisuke Maeda ◽  
Kanae Ashida ◽  
Keita Iguchi ◽  
Svetlana A. Chechetka ◽  
Ayaka Hijikata ◽  
...  

2021 ◽  
Vol 11 (11) ◽  
pp. 5297
Author(s):  
Stavros D. Veresoglou ◽  
Leonie Grünfeld ◽  
Magkdi Mola

The roots of most plants host diverse assemblages of arbuscular mycorrhizal fungi (AMF), which benefit the plant hosts in diverse ways. Even though we understand that such AMF assemblages are non-random, we do not fully appreciate whether and how environmental settings can make them more or less predictable in time and space. Here we present results from three controlled experiments, where we manipulated two environmental parameters, habitat connectance and habitat quality, to address the degree to which plant roots in archipelagos of high connectivity and invariable habitats are colonized with (i) less diverse and (ii) easier to predict AMF assemblages. We observed no differences in diversity across our manipulations. We show, however, that mixing habitats and varying connectivity render AMF assemblages less predictable, which we could only detect within and not between our experimental units. We also demonstrate that none of our manipulations favoured any specific AMF taxa. We present here evidence that the community structure of AMF is less responsive to spatio-temporal manipulations than root colonization rates which is a facet of the symbiosis which we currently poorly understand.


2021 ◽  
Vol 9 (8) ◽  
pp. 1622
Author(s):  
Basanta Dhodary ◽  
Dieter Spiteller

Leaf-cutting ants live in mutualistic symbiosis with their garden fungus Leucoagaricus gongylophorus that can be attacked by the specialized pathogenic fungus Escovopsis. Actinomyces symbionts from Acromyrmex leaf-cutting ants contribute to protect L. gongylophorus against pathogens. The symbiont Streptomyces sp. Av25_4 exhibited strong activity against Escovopsis weberi in co-cultivation assays. Experiments physically separating E. weberi and Streptomyces sp. Av25_4 allowing only exchange of volatiles revealed that Streptomyces sp. Av25_4 produces a volatile antifungal. Volatile compounds from Streptomyces sp. Av25_4 were collected by closed loop stripping. Analysis by NMR revealed that Streptomyces sp. Av25_4 overproduces ammonia (up to 8 mM) which completely inhibited the growth of E. weberi due to its strong basic pH. Additionally, other symbionts from different Acromyrmex ants inhibited E. weberi by production of ammonia. The waste of ca. one third of Acomyrmex and Atta leaf-cutting ant colonies was strongly basic due to ammonia (up to ca. 8 mM) suggesting its role in nest hygiene. Not only complex and metabolically costly secondary metabolites, such as polyketides, but simple ammonia released by symbionts of leaf-cutting ants can contribute to control the growth of Escovopsis that is sensitive to ammonia in contrast to the garden fungus L. gongylophorus.


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