scholarly journals Acaulospora as the Dominant Arbuscular Mycorrhizal Fungi in Organic Lowland Rice Paddies Improves Phosphorus Availability in Soils

2021 ◽  
Vol 14 (1) ◽  
pp. 31
Author(s):  
Khachonphong Nopphakat ◽  
Phanthipha Runsaeng ◽  
Lompong Klinnawee

Flooding in rainfed lowlands greatly impairs the mutualistic relationship between indigenous arbuscular mycorrhizal fungi (AMF) and rice. In flooded soils, root colonization by AMF is arrested, but some AMF genera, defined as the core AMF, remain present. However, the core AMF in rainfed lowlands and their symbiotic roles remain unknown. Here, we showed that Acaulospora fungi were the core AMF in rice seedling roots of the Sangyod Muang Phatthalung (SMP) landrace rice variety grown in non-flooded and flooded paddy soils. Subsequently, indigenous Acaulospora spores were propagated by trap cultures using maize as the host plants. Therefore, to clarify the roles of cultured Acaulospora spores in a symbiotic partnership, the model japonica rice variety Nipponbare was grown in sterile soil inoculated with Acaulospora spores, and recolonized with a native microbial filtrate from the organic rice paddy soil. Our data demonstrated that the inoculation of Acaulospora spores in well-drained soil under a nutrient-sufficient condition for six weeks enabled 70 percent of the rice roots to be colonized by the fungi, leading to higher phosphate (Pi) accumulation in the mycorrhizal roots. Unexpectedly, the growth of rice seedlings was significantly suppressed by inoculation while photosynthetic parameters such as fractions of incoming light energy and relative chlorophyll content were unaltered. In the soil, the Acaulospora fungi increased soil phosphorus (P) availability by enhancing the secretion of acid phosphatase in the mycorrhizal roots. The findings of this work elucidate the symbiotic roles of the dominant Acaulospora fungi from lowland rice paddies.

2021 ◽  
Vol 12 ◽  
Author(s):  
Hassan Etesami ◽  
Byoung Ryong Jeong ◽  
Bernard R. Glick

Phosphorus (P) availability is usually low in soils around the globe. Most soils have a deficiency of available P; if they are not fertilized, they will not be able to satisfy the P requirement of plants. P fertilization is generally recommended to manage soil P deficiency; however, the low efficacy of P fertilizers in acidic and in calcareous soils restricts P availability. Moreover, the overuse of P fertilizers is a cause of significant environmental concerns. However, the use of arbuscular mycorrhizal fungi (AMF), phosphate–solubilizing bacteria (PSB), and the addition of silicon (Si) are effective and economical ways to improve the availability and efficacy of P. In this review the contributions of Si, PSB, and AMF in improving the P availability is discussed. Based on what is known about them, the combined strategy of using Si along with AMF and PSB may be highly useful in improving the P availability and as a result, its uptake by plants compared to using either of them alone. A better understanding how the two microorganism groups and Si interact is crucial to preserving soil fertility and improving the economic and environmental sustainability of crop production in P deficient soils. This review summarizes and discusses the current knowledge concerning the interactions among AMF, PSB, and Si in enhancing P availability and its uptake by plants in sustainable agriculture.


2019 ◽  
Vol 42 ◽  
pp. e42477 ◽  
Author(s):  
Rosalba Ortega Fors ◽  
Orivaldo José Saggin Júnior ◽  
Marco Aurélio Carbone Carneiro ◽  
Ricardo Luis Louro Berbara

The present study aimed to select efficient arbuscular mycorrhizal fungi (AMF) for sugarcane growth and P nutrition in four soils that spontaneously contained dark septate endophytes (DSE). The effect of nine AMF isolates was evaluated individually in sugarcane presprouted seedlings (SP81-3250) grown under greenhouse conditions for a 120-day period. The isolates that stimulated plant growth in the soils with low P availability were Acaulospora colombiana (ACOL), Claroideoglomus etunicatum (CETU), Gigaspora margarita (GMAR), Rhizophagus clarus (RCLA) and Scutellospora calospora (SCAL). Compared to the Yellow Argisol, which had the highest P level, the Red-Yellow Argisol, with an intermediate P content, increased plant height. Compared to the other treatments, inoculation with ACOL, RCLA, and SCAL resulted in higher foliar P content in plants grown in soils with high to intermediate P levels. Root colonization by AMF and DSE was verified in the plants, with the coexistence of both fungal groups in the same plant and/or root fragment. However, AMF colonization was low compared to DSE colonization. The cooccurrence of DSE and AMF was higher in the plants inoculated with ACOL, RCLA, SCAL, and Dentiscutata heterogama. ACOL, CETU, GMAR, RCLA, and SCAL are AMF isolates that have the potential to establish a mycorrhizal inoculant for sugarcane that would be effective in several soils.


2021 ◽  
Author(s):  
Leonie H Luginbuehl ◽  
Harrie van Erp ◽  
Henry Cheeld ◽  
Kirankumar S Mysore ◽  
Jiangqi Wen ◽  
...  

ABSTRACTArbuscular mycorrhizal fungi (AMF) rely on their host plants to provide them with fatty acids (FA), but the precise form(s) in which they are supplied is still unclear. Here we show that ectopic expression of the transcription factor REQUIRED FOR ARBUSCULAR MYCORRHIZATION 1 (RAM1) can drive secretion of 2-monoacylglycerols (2MGs) from Medicago truncatula roots and that their main FA moiety is palmitic acid, although myristic acid and stearic acid were also detected. RAM1-dependent 2MG secretion requires the acyl-acyl carrier protein thioesterase FATM, the glycerol-3-phosphate (G3P) acyltransferase RAM2 and the ATP binding cassette transporter STR. Furthermore, 14C glycerol labelling experiments using mycorrhizal M. truncatula roots that are deficient in glycerol kinase, FAD-dependent G3P dehydrogenase and the G3P acyltransferase RAM2 suggest that most of the glyceryl moieties in Rhizophagus irregularis storage lipids are provided by their host plant through the 2MG pathway. Taken together, our data support the hypothesis that the plant exports 2MGs across the peri-arbuscular membrane in mycorrhizal roots and that the AMF receive and utilise both the FA and glyceryl moieties to make their storage lipids.


1989 ◽  
Vol 67 (3) ◽  
pp. 687-693 ◽  
Author(s):  
J. P. Thompson ◽  
G. B. Wildermuth

The roots of 37 crop and pasture species were assessed for vesicular–arbuscular mycorrhizae in a vertisol containing spores of vesicular–arbuscular mycorrhizal fungi mainly Glomus mosseae, and of the pathogenic fungus, Bipolaris sorokiniana. The level of mycorrhizal colonization of different hosts is an important aspect of managing crop sequences to reduce "long fallow disorder." All species except rapeseed in the Cruciferae and lupin in the Leguminosae were hosts, although perennial rye grass in the Gramineae had only very slight colonization. The percent root length colonized as assessed by the grid-intersect method ranged up to 60.5% for wheat in the winter series and up to 98.4% for mungbean in the summer series. Greatest weights of mycorrhizal roots were produced by phalaris grass, chickpea, safflower, cocksfoot, lucerne, and barley in the winter series and by lucerne, maize, canary seed, Sudan grass, grain sorghum, and buffel grass in the summer series. Although Gramineae as a group tends to have fine roots with a low percentage of mycorrhizal colonization, the total weight of mycorrhizal roots can be large, and they should be at least equal to legumes in effectiveness for breaking long fallow disorder. Percentages of mycorrhizal colonization determined by the grid-intersect and three slide methods were generally well correlated with one another, but all were less strongly correlated with weight of mycorrhizal roots for winter crops and were entirely uncorrelated with weight of mycorrhizal roots for summer crops. Significant inverse-regression relationships were obtained between infection of root segments (but not of stem bases) by B. sorokiniana and root colonization with vesicular–arbuscular mycorrhizae, indicating that vesicular–arbuscular mycorrhizal fungi antagonise root infection by B. sorokiniana.


2005 ◽  
Vol 62 (4) ◽  
pp. 389-394 ◽  
Author(s):  
Sara Adrián López de Andrade ◽  
Renato Atílio Jorge ◽  
Adriana Parada Dias da Silveira

The effect of cadmium (Cd) on mycorrhizal association and on shoot and root Cd concentration was investigated in jackbean plants under hydroponic conditions. The treatments consisted of the inoculation of three different species of arbuscular mycorrhizal fungi (AMF), Glomus etunicatum, G. intraradices and G. macrocarpum, and a non-inoculated control, two Cd (0 and 5 µmol L-1) and two P (1 and 10 mg L-1) levels in the nutrient solution. Mycorrhizal colonization, length of AMF extraradical mycelium, guaiacol peroxidase activity in roots, plant growth and root and shoot Cd and P concentrations were determined. Mycorrhizal status did not promote jackbean growth but in most of the cases mycorrhization increased root and shoot Cd concentrations. Cd ions were accumulated mainly in roots and only small amounts were translocated to the shoot. Cd addition did not affect root colonization by AMF but the AM extraradical mycelium (ERM) was sensitive to the added Cd. ERM length was reduced by 25% in the presence of Cd. This reduction was more pronounced under conditions of low P concentration. Also at this P concentration, Cd addition decreased guaiacol peroxidase activity in non-mycorrhizal roots and in roots colonized by G. macrocarpum. However, mycorrhizal roots maintained lower values of peroxidase activity. G. etunicatum showed the best performance when associated to jackbean plants and it could be a promising association for phytoremediation of Cd- contaminated soil.


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