scholarly journals Arbuscular Mycorrhizal Fungi Regulate MAPK Pathway Genes Expression and Enhance Drought Tolerance of Populus Simonii × P. Nigra Seedlings

Author(s):  
Jing Tao ◽  
Fengxin Dong ◽  
Yihan Wang ◽  
Hui Chen ◽  
Ming Tang

Abstract Background: Arbuscular mycorrhizal fungi (AMF) form a symbiotic relationship with host plants, which can promote plants to absorb more water and nutrients, and thus improve the stress resistance of plants. Our study aimed to investigate the effects of Rhizophagus irregularis on Populus simonii × P. nigra seedlings under drought stress. Results: The experiment was a completely random design with two water conditions (well-watered or drought stress) and two AMF treatments (inoculated with or without R. irregularis). Our results showed that mycorrhizal seedlings performed less oxidative damage and stronger tolerance of drought, which recorded higher photosynthesis and less concentrations of Malondialdehyde (MDA), H2O2, and proline under drought stress versus non-mycorrhizal seedlings. Under drought stress, AMF inoculation reduced soluble sugar concentration in leaves but promoted its accumulation in roots. The superoxide dismutase (SOD) activity in leaves and roots, and catalase (CAT) activity in roots of mycorrhizal seedlings were lower than non-mycorrhizal seedlings, but CAT activity in leaves of mycorrhizal seedlings was higher than non-mycorrhizal seedlings under drought stress. Drought stress and AMF inoculation both induced the expressions of MAPKs of P. simonii × P. nigra, but the expression patterns of MAPKs under four treatments were obviously different.Conclusions: Overall, our results demonstrated that mycorrhizal seedlings had less oxidative damage and stronger tolerance to drought. MAPKs expressions of P. simonii×P. nigra (PsnMAPKs) were induced by drought stress and AMF inoculation, and the expression patterns of PsnMAPKs in response to drought stress were different between mycorrhizal and non-mycorrhizal seedlings. Non-mycorrhizal seedlings may be adapted to drought by up-regulating MAPKs expressions leading to stomatal closure. Drought stress decreased serval PsnMAPKs expressions induced by AMF inoculation, which may be associated with mycorrhizal colonization.

2015 ◽  
Vol 28 (4) ◽  
pp. 408-419 ◽  
Author(s):  
Zhilei Liu ◽  
Yuanjing Li ◽  
Lina Ma ◽  
Haichao Wei ◽  
Jianfeng Zhang ◽  
...  

Mitogen-activated protein kinase (MAPK) cascades play important roles in the stress response in both plants and microorganisms. The mycorrhizal symbiosis established between arbuscular mycorrhizal fungi (AMF) and plants can enhance plant drought tolerance, which might be closely related to the fungal MAPK response and the molecular dialogue between fungal and soybean MAPK cascades. To verify the above hypothesis, germinal Glomus intraradices (syn. Rhizophagus irregularis) spores and potted experiments were conducted. The results showed that AMF GiMAPKs with high homology with MAPKs from Saccharomyces cerevisiae had different gene expression patterns under different conditions (nitrogen starvation, abscisic acid treatment, and drought). Drought stress upregulated the levels of fungi and soybean MAPK transcripts in mycorrhizal soybean roots, indicating the possibility of a molecular dialogue between the two symbiotic sides of symbiosis and suggesting that they might cooperate to regulate the mycorrhizal soybean drought-stress response. Meanwhile, the changes in hydrogen peroxide, soluble sugar, and proline levels in mycorrhizal soybean as well as in the accelerated exchange of carbon and nitrogen in the symbionts were contributable to drought adaptation of the host plants. Thus, it can be preliminarily inferred that the interactions of MAPK signals on both sides, symbiotic fungus and plant, might regulate the response of symbiosis and, thus, improve the resistance of mycorrhizal soybean to drought stress.


Author(s):  
Bo Shu ◽  
YaChao Xie ◽  
Fei Zhang ◽  
Dejian Zhang ◽  
Chunyan Liu ◽  
...  

Calmodulin-like (CML) proteins represent a diverse family of protein in plants, and play significant roles in biotic and abiotic stress responses. However, the involvement of citrus CMLs in plant responses to drought stress (abiotic stress) and arbuscular mycorrhizal fungi (AMF) colonization remain relatively unknown. We characterized the citrus CML genes by analyzing the EF-hand domains and a genome-wide search, and identified a total of 38 such genes, distributed across at least nine chromosomes. Six tandem duplication clusters were observed in the CsCMLs, and 12 CsCMLs exhibited syntenic relationships with Arabidopsis thaliana CMLs. Gene expression analysis showed that 29 CsCMLs were expressed in the roots, and exhibited differential expression patterns. The regulation of CsCMLs expression was not consistent with the cis-elements identified in their promoters. CsCML2, 3, and 5 were upregulated in response to drought stress, and AMF colonization repressed the expression of CsCML7, 9, 12, 13,20, 27, 28, and 35,and induced that of CsCML1, 2, 3, 5, 8, 10, 11, 14, 15, 16, 18, 25, 30, 33, and 37. Furthermore, AMF colonization and drought stress exerted a synergistic effect, evident from the enhanced repression of CsCML7, 9, 12, 13, 27, 28, and 35 and enhanced expression of CsCML2, 3, and 5 under AMF colonization and drought stress. The present study provides valuable insights into the CsCML gene family and its responses to AMF colonization and drought stress.


Horticulturae ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 230
Author(s):  
Fan Yang ◽  
Yupeng Pan ◽  
Ahmad Ali ◽  
Siyu Zhang ◽  
Xiaxia Li ◽  
...  

Garlic has a strong ability of selenium (Se) accumulation and is one of the best target crops for Se biofortification. Arbuscular mycorrhizal fungi (AMF) inoculation might enhance the nutritional qualities and the absorption ability of exogenous Se in plants. However, little is known about the exogenous Se application and AMF inoculation on garlic. Here, we evaluated the effects of different concentrations of exogenous Se on the growth, nutritional quality, and selenium enrichment of garlic. The results demonstrated that significantly higher Se content of garlic bulb was found in exogenous Se treated plants, and the Se accumulation was improved with the increasing of Se supply. Low application of exogenous Se appreciably improved the yield and the contents of soluble sugar and allicin in garlic bulbs, but the opposite was observed at high Se concentration. Furthermore, AMF inoculation significantly reduced the inhibition effect of high concentration Se on garlic. AMF supply was effective in improving the growth and nutritional indicators of garlic, which promoted the exogenous Se utilization rate when combined with 10 mg/L exogenous Se treatment. The results will provide a more theoretical basis for the production of high-quality selenium enrichment garlic.


2017 ◽  
Vol 45 (1) ◽  
pp. 220-224 ◽  
Author(s):  
Xiao-Qing TUO ◽  
Li HE ◽  
Ying-Ning ZOU

White clover is extremely susceptive to drought stress (DS), while it is not clear whether arbuscular mycorrhizal fungi (AMF) enhance drought tolerance of the plant. This study was carried out to evaluate effects of two AMF species, Funneliformis mosseae and Paraglomus occultum, on flavonoid, soluble protein, proline, and nutrient uptake in roots of white clover under well-watered (WW) and DS conditions. Root colonization by F. mosseae and P. occultum was heavily decreased by 7-week DS treatment. Mycorrhizal plants showed considerably greater biomass production in shoot, root, and total (shoot+root) than non-mycorrhizal plants, irrespective of soil water status. AMF inoculation led to significantly higher root soluble protein and proline accumulation under WW and DS and root flavonoid level under DS, regardless of AMF species. Root N, P, K and Cu concentrations were dramatically increased by mycorrhization under WW and DS, and root Ca, Mg, Fe, and Mn levels were significantly higher in AMF plants than in non-AMF plants under WW. It concluded that AMF strongly enhanced plant growth and drought tolerance of white clover by greater nutrient absorption and protective substances (soluble protein, proline, and flavonoid) accumulation.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Abderrahim Boutasknit ◽  
Marouane Baslam ◽  
Mohamed Ait-El-Mokhtar ◽  
Mohamed Anli ◽  
Raja Ben-Laouane ◽  
...  

AbstractIn the current study, an eco-friendly management technology to improve young carob (Ceratonia siliqua L.) tree tolerance to water deficit was set up by using single or combined treatments of arbuscular mycorrhizal fungi (AMF) and/or compost (C). Two groups of young carob have been installed: (i) carob cultivated under well-watered conditions (WW; 70% field capacity (FC)) and (ii) where the plants were drought-stressed (DS; 35% FC) during 2, 4, 6, and 8 months. The effect of used biofertilizers on the course of growth, physiological (photosynthetic traits, water status, osmolytes, and mineral content), and biochemical (hydrogen peroxide (H2O2), oxidative damage to lipids (malondialdehyde (MDA), and membrane stability (MS)) traits in response to short- and long-term droughts were assessed. The dual application of AMF and C (C + AMF) boosted growth, physiological and biochemical parameters, and nutrient uptake in carob under WW and DS. After eight months, C + AMF significantly enhanced stomatal conductance by 20%, maximum photochemical efficiency of PSII by 7%, leaf water potential by 23%, chlorophyll and carotenoid by 40%, plant uptake of mineral nutrients (P by 75%, N by 46%, K+ by 35%, and Ca2+ by 40%), concentrations of soluble sugar by 40%, and protein content by 44% than controls under DS conditions. Notably, C + AMF reduced the accumulation of H2O2 and MDA content to a greater degree and increased MS. In contrast, enzyme activities (superoxide dismutase, catalase, peroxidase, and polyphenoloxidase) significantly increased in C + AMF plants under DS. Overall, our findings suggest that the pairing of C + AMF can mediate superior drought tolerance in young carob trees by increasing leaf stomatal conductance, cellular water content, higher solute concentration, and defense response against oxidative damage during the prolonged period of DS.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Mohamed S. Sheteiwy ◽  
Dina Fathi Ismail Ali ◽  
You-Cai Xiong ◽  
Marian Brestic ◽  
Milan Skalicky ◽  
...  

Abstract Background The present study aims to study the effects of biofertilizers potential of Arbuscular Mycorrhizal Fungi (AMF) and Bradyrhizobium japonicum (B. japonicum) strains on yield and growth of drought stressed soybean (Giza 111) plants at early pod stage (50 days from sowing, R3) and seed development stage (90 days from sowing, R5). Results Highest plant biomass, leaf chlorophyll content, nodulation, and grain yield were observed in the unstressed plants as compared with water stressed-plants at R3 and R5 stages. At soil rhizosphere level, AMF and B. japonicum treatments improved bacterial counts and the activities of the enzymes (dehydrogenase and phosphatase) under well-watered and drought stress conditions. Irrespective of the drought effects, AMF and B. japonicum treatments improved the growth and yield of soybean under both drought (restrained irrigation) and adequately-watered conditions as compared with untreated plants. The current study revealed that AMF and B. japonicum improved catalase (CAT) and peroxidase (POD) in the seeds, and a reverse trend was observed in case of malonaldehyde (MDA) and proline under drought stress. The relative expression of the CAT and POD genes was up-regulated by the application of biofertilizers treatments under drought stress condition. Interestingly a reverse trend was observed in the case of the relative expression of the genes involved in the proline metabolism such as P5CS, P5CR, PDH, and P5CDH under the same conditions. The present study suggests that biofertilizers diminished the inhibitory effect of drought stress on cell development and resulted in a shorter time for DNA accumulation and the cycle of cell division. There were notable changes in the activities of enzymes involved in the secondary metabolism and expression levels of GmSPS1, GmSuSy, and GmC-INV in the plants treated with biofertilizers and exposed to the drought stress at both R3 and R5 stages. These changes in the activities of secondary metabolism and their transcriptional levels caused by biofertilizers may contribute to increasing soybean tolerance to drought stress. Conclusions The results of this study suggest that application of biofertilizers to soybean plants is a promising approach to alleviate drought stress effects on growth performance of soybean plants. The integrated application of biofertilizers may help to obtain improved resilience of the agro ecosystems to adverse impacts of climate change and help to improve soil fertility and plant growth under drought stress.


2017 ◽  
Vol 12 (5) ◽  
pp. 159
Author(s):  
Marlina Puspita Sari ◽  
Bambang Hadisutrisno ◽  
Suryanti Suryanti

Arbuscular mycorrhizal fungi (AMF) is known to improve the growth of shallot (Allium cepa var. aggregatum) and strengthen the resistance of plants toward disease infection.  This research aimed to find out the roles of AMF in suppressing the development of purple blotch disease caused by  Alternaria sp. on shallot in Caturtunggal, Sleman, Yogyakarta.  Inoculation of AMF either on fertilization of N, P, K or without fertilization treatment resulted on higher plant height and number of leaves compared to those without AMF inoculation. The plant inoculated with AMF had lower purple blotch disease intensity and disease progression than control and fungicide treatment. The result showed that AMF, in addition to act as the bio-fertilizer, is a potential to be a biocontrol agent.


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