Status and Need of Research on Rhizobia and Arbuscular Mycorrhizal Fungi Associated with Leguminous Plants in Saudi Arabia (original) (raw)
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Acta Scientiarum Polonorum Hortorum Cultus
The tripartite associations of arbuscular mycorrhizal fungi (AMF), rhizobia and legumes play a vital role in preserving and even restoring fertility of poor and eroded soils. The present study attempted to quantify relationship between legumes and symbiotic microorganisms (rhizobia and mycorrhizal fungi) by describing the mycorrhizal status and the occurrence of nodualtion of legumes growing in different areas of Jazan. The effect of legume species on soil microbial biomass was also investigated. Mycorrhizal and nodulation intensity varied greatly between legume species. The higher number of nodules (14 nodules per plant) and mycorrhization intensity (54%) were registered in root of Argyrolobium arabicum. Rhizosphere soils of all legume species harbored higher AMF fungal spores than bulk soils. Our results suggest also a significant effect of legumes species on soil microbial biomass. Thus, legume species investigated in this study are potentially useful for replanting and soil protection of most degraded regions of Saudi Arabia.
Soil Biology and Biochemistry, 2007
We investigated how the rate of colonization by indigenous arbuscular mycorrhizal fungi (AMF) affects the interaction between AMF, Sinorrhizobium meliloti and Medicago truncatula Gaertn. To generate a differential inoculum potential of indigenous AMF, five cycles of wheat, each of 1 month, were grown in sieved or undisturbed soil before M. truncatula was sown. The early colonization of M. truncatula roots by indigenous AMF was faster in undisturbed soil compared with sieved soil, but by pod-fill the frequency of hyphae, arbuscules and vesicles was similar in both treatments. At this latter stage, M. truncatula grown in undisturbed soil had accumulated a greater biomass in aboveground tissues, had a greater P concentration and derived more N from the atmosphere than plants grown in disturbed soil, although soil compaction resulted in plants having a smaller root system than those from disturbed soil. The difference in plant P content could not be explained by modifications in hydrolytic soil enzymes related to the P cycle as the activity of acid phosphatase was greater in sieved than in undisturbed soil, and the activity of alkaline phosphatase was unaffected by the treatment. Thus, the results observed were a consequence of the different rates of AMF colonization caused by soil disturbance. Together with earlier results for soybean, this study confirms that soil disturbance modifies the interaction between indigenous AMF, rhizobia and legumes leading to a reduced efficacy of the bacterial symbiont.
Arbuscular Mycorrhizal Fungi Diversity in Two Different Regions in Saudi Arabia
International Journal of Current Microbiology and Applied Sciences, 2018
Desert environment is very challenging one for plant life due to the scarce, sporadic precipitation, nutrient deficiency, intense solar radiation, and the high temperature (Apple, 2010). Hence, desert plants show unique reproductive biology, well-adapted ecophysiological, anatomical characteristics, and specialized metabolism and survival abilities. Plant-associated microorganisms are critical components of native desert vegetation in which they are playing an active role in the survival of their plant partners. Soil drought is a widespread problem in the World, which restricts the plant growth and biomass production; particularly in arid and semi-arid regions such as in Saudi Arabia. Drought stress generally occurs when available soil water is reduced and water is continuously lost by the transpiration and/or evaporation as a result of atmospheric conditions.
Frontiers in Genetics, 2020
Legumes are unique among plants as they can obtain nitrogen through symbiosis with nitrogen-fixing rhizobia that form root nodules in the host plants. Therefore they are valuable crops for sustainable agriculture. Increasing nitrogen fixation efficiency is not only important for achieving better plant growth and yield, but it is also crucial for reducing the use of nitrogen fertilizer. Arbuscular mycorrhizal fungi (AMF) are another group of important beneficial microorganisms that form symbiotic relationships with legumes. AMF can promote host plant growth by providing mineral nutrients and improving the soil ecosystem. The trilateral legume-rhizobia-AMF symbiotic relationships also enhance plant development and tolerance against biotic and abiotic stresses. It is known that domestication and agricultural activities have led to the reduced genetic diversity of cultivated germplasms and higher sensitivity to nutrient deficiencies in crop plants, but how domestication has impacted the capability of legumes to establish beneficial associations with rhizospheric microbes (including rhizobia and fungi) is not well-studied. In this review, we will discuss the impacts of domestication and agricultural practices on the interactions between legumes and soil microbes, focusing on the effects on AMF and rhizobial symbioses and hence nutrient acquisition by host legumes. In addition, we will summarize the genes involved in legume-microbe interactions and studies that have contributed to a better understanding of legume symbiotic associations using metabolic modeling.
Agricultural Science Digest, Volume 44 Issue 1: 06-13 (February), 2024
Background: Medicago sativa, Medicago truncatula and Trifolium rubens are legumes widely distributed in Algeria. These species hold ecological and agricultural significance and serve as a natural resource for combating desertification and as livestock fodder. Methods: Comparative investigations of arbuscular mycorrhizal fungi (AMF) colonization in the roots of these leguminous species were conducted. The physicochemical and microbiological attributes of AMF's infectious potential were explored for all three species. The presence or absence of endomycorrhizal structures was assessed in these species. Result: The mycorrhizal infectious potential of the flora was significantly enhanced in the case of Medicago truncatula when compared to Trifolium rubens. Mycorrhization occurred at a frequency exceeding 80% in all three species. The impact of legume mycorrhizal fungi colonization on soil physicochemical properties was examined, revealing alterations in soil biological fertility, particularly in terms of phosphate and nitrogen content. Medicago truncatula exhibited a more pronounced positive influence on soil physical, chemical and microbiological characteristics when compared to Medicago sativa and Trifolium rubens. Consequently, these herbaceous species can be employed as nurse plants (facilitators) or as bio-fertilizers.
New Phytologist, 1997
Arbuscular mycorrhizal (AM) fungi, Rhizobium bacteria and plant-growth-promoting rhizobacteria (PGPR) were isolated from a representative area of a desertified semi-arid ecosystem in the southeast of Spain. Microbial isolates were characterized and screened for effectiveness by a single-inoculation trial in soil microcosms. Anthvllis cytisoides L., a mycotrophic pioneer legume, dominant in the target mediterranean ecosystem, was the test plant. Several microbial cultures from existing collections were also included in the screening process. Two AM fungi {Glomus coronatum, native, and Glomus intraradices, exotic), two Rhizobium bacteria (NR4 and NR9, both native) and two PGPR (A2, native, and E, exotic) were selected. A further screening for the appropriate double and triple combinations of microbial inoculants was then performed. The parameters evaluated were biomass accumulation and allocation, N and P uptake, N^-fixation (^^N) and specific root length. Overall, G. coronatum, native in the field site was more effective than the exotic G. intraradices in co-inoculation treatments. In general, our results support the importance of physiological and genetic adaptation of microbes to the whole environment, thus local isolates must be involved. Many microbial combinations were effective in improving either plant development, nutrient uptake, Nj-fixation or root system quality. Selective and specific functional compatibility relationships in plant response between the microbial inoculants, were observed. Despite the difficulty of selecting a multifunctional microbial inoculum, appropriate microbial combinations can be recommended for a given biotechnological input related to improyement of plant performance. This could be exploited in nursery production of target plant species endowed with optimized rhizosphere/mycorrhizosphere systems that can be tailored to help plants to establish and survive in nutrient-deficient, degraded habitats. The relevance of this microbial-based approach in the context of a reclamation strategy addressed to environmental sustainability purposes is discussed.
Diversity
Arbuscular mycorrhizal fungi (AMF) are determinant for the performance of plant communities and for the functionality of terrestrial ecosystems. In natural ecosystems, grazing can have a major impact on mycorrhizal fungi and consequently on plant growth. The objective of this study was to evaluate the statements referred above in Mediterranean arid areas in Tunisia. Root samples and rhizosphere soils of five dominant herbaceous plants were studied at six distinct arid sites differing on soil proprieties and grazing intensity. At each site, chemical and dynamic properties of the soil were characterized as well as the AMF colonization intensity and the soil functionality. Results showed that the mycorrhizal frequency and intensity and spore density, varied between plants in the same site and, for each plant, between sites and evidenced a positive effect of mycorrhized plants on soil microbial activity. Grazing and soil properties strongly affected AMF composition and the soil microbia...
From isolation to application: a case study of arbuscular mycorrhizal fungi of the Arabian Peninsula
Symbiosis, 2021
The vegetation in the Arabian Peninsula experiences drought, heat, soil salinity, and low fertility, mainly due to low phosphorus (P) availability. The beneficial mycorrhizal symbiosis between plants and arbuscular mycorrhizal fungi (AMF) is a key factor supporting plant growth under such environmental conditions. Therefore, AMF strains isolated from these soils might be useful as biotechnological tools for agriculture and revegetation practices in the region. Here we present a pioneering program to isolate, identify, and apply AMF isolated from rhizosphere soils of agricultural and natural habitats, namely date palm plantations and five native desert plants, respectively in the Southern Arabian Peninsula. We established taxonomically unique AMF species as single-spore cultures as part of an expanding collection of AMF strains adapted to arid ecosystems. Preliminary experiments were conducted to evaluate the abilities of these AMF strains to promote seedling growth of a main crop Ph...
Survey of Indigenous Arbuscular Mycorrhizal Fungi under Ecosystem of Saudi Arabia
Journal of Pure and Applied Microbiology, 2014
Distribution and colonization of arbuscular mycorrhizal fungi were studied under plant vegetation, which was found growing naturally in the near edges of the old road between Jeddah to Mecca at western of Saudi Arabia kingdom, during the period between May to September 2013. One hundred and twenty five roots and rhizospheric soils of 12 plant species belonging to 8 families from 25 sites at different 3 locations were collected and examined. Mycorrhizal fungi were recorded in 11 taxa, 3 genera, 3 families, 2 orders, one class and one phylum from all sites. On the generic level, Glomus was the dominant genus in rhizospheric soil, which Glomus sinusum (Gerd. & Bakshi) Almeida & Schenck and G. macrocarpum Tulasne & Tulasne were the dominant species associated with examined plant species. The plants to family Asclepiadaceae were contained of 43.85% from total collected spores in all study sites. On the other hand the average of distribution species of mycorrhizal fungi in all examined plants between 2 and 5 species for plant family. The G. macrocarpum was recorded in 10 sites out of 25 sites collected from different locations.