scholarly journals Fungicides Added to Potting Substrate Affect Mycorrhizal Symbiosis between a Peach-Almond Rootstock and Glomus sp.

HortScience ◽  
1998 ◽  
Vol 33 (7) ◽  
pp. 1217-1219 ◽  
Author(s):  
X. Fontanet ◽  
V. Estaún ◽  
A. Camprubí ◽  
C. Calvet

Prior to the commercial use of arbuscular mycorrhiza (AM) in the nursery, the effects of commonly used pesticides on symbiosis must be evaluated. Metalaxyl and propamocarb are two fungicides added to potting substrates to prevent diseases caused by phycomycetes. Both fungicides were incorporated into the potting substrate before the inoculation and planting of the peach-almond hybrid rootstock GF677 (Prunus persica L. × Prunus dulcis Mill. D.A. Webb). The AM fungus used were Glomus mosseae (Nicol. & Gerd.) Gerdemann & Trappe and Glomus intraradices Schenck & Smith. Glomus intraradices was not affected by either fungicide; however, metalaxyl adversely affected root colonization by G. mosseae and decreased rhizosphere activity as measured by esterase activity. Chemical names used: N-(2-methoxyacetyl)-N-(2,6-xylyl)-DL-alaninate) (metalaxyl); propyl 3(dimethylamino)propylcarbamate (propamocarb).

1994 ◽  
Vol 3 (3) ◽  
pp. 263-267 ◽  
Author(s):  
Victoria Estaun ◽  
Cinta Calvet ◽  
Amelia Camprubi

The receptivity of two peat based potting mixes to AM colonisation was studied with the almond x peach clone GF677 as host plant. Four fungi were assayed: Glomus mosseae, Glomus intraradices, Glomus sp (E3) and Acaulospora laevis. The response of the four fungi varied with the potting mix used, stressing the importance of the growing media on the functionality of the mycorrhizal symbiosis.


1999 ◽  
Vol 77 (6) ◽  
pp. 891-897 ◽  
Author(s):  
Alexandra Pinior ◽  
Urs Wyss ◽  
Yves Piché ◽  
Horst Vierheilig

The effect of root exudates from non-mycorrhizal and mycorrhizal cucumber (Cucumis sativus L.) plants colonized by one of three arbuscular mycorrhizal fungi (Gigaspora rosea Nicolson & Schenck, Glomus intraradices Smith & Schenck, or Glomus mosseae (Nicolson & Gerdemann) Gerd. & Trappe) on hyphal growth of Gi. rosea and G. intraradices in axenic culture and on root colonization by G. mosseae in soil was investigated. Root exudates from non-mycorrhizal cucumber plants clearly stimulated hyphal growth, whereas root exudates from all mycorrhizal cucumber plants tested showed no stimulation of the hyphal growth of Gi. rosea and only a slight stimulation of the hyphal growth of G. intraradices. Moreover, root exudates from all mycorrhizal cucumber plants inhibited root colonization by G. mosseae compared with the water-treated controls. These results suggest that plants colonized by AM fungi regulate further mycorrhization via their root exudates.Key words: Glomales, Gigaspora rosea, Glomus intraradices, Glomus mosseae, root exudates, regulation.


1998 ◽  
Vol 123 (3) ◽  
pp. 342-347 ◽  
Author(s):  
J. Pinochet ◽  
A. Camprubí ◽  
C. Calvet ◽  
C. Fernández ◽  
R. Rodríguez Kábana

The beneficial effects of early mycorrhizal inoculation with two arbuscular fungi, Glomus mosseae (Nicol. and Gerd.) Gerd. and Trappe and Glomus intraradices Schenck and Smith, were evaluated on Myrobalan 29 C (Prunus cerasifera × Prunus munsoniana Wight and Edr.) plum rootstock in soil infested or noninfested with the root lesion nematode Pratylenchus vulnus Allen and Jensen under microplot conditions. During this two year study, mycorrhizal colonization did not affect the number of nematodes per gram of root in plants infected with P. vulnus. In contrast, P. vulnus significantly decreased the percentage of mycorrhizal root colonization. Most elements were within sufficiency levels for plum by foliar analysis, although low P and deficient Fe and Cu levels were detected in P. vulnus treatments. Early mycorrhizal inoculation with G. mosseae favored plant growth after 20 months, but in soils infested by P. vulnus, only G. intraradices increased the tolerance of Myrobalan 29 C plum rootstock to damaging nematode levels by stimulating plant nutrition and vegetative growth.


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.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Manoj-Kumar Arthikala ◽  
Kalpana Nanjareddy ◽  
Lourdes Blanco ◽  
Xóchitl Alvarado-Affantranger ◽  
Miguel Lara

AbstractTarget of rapamycin (TOR) is a conserved central growth regulator in eukaryotes that has a key role in maintaining cellular nutrient and energy status. Arbuscular mycorrhizal (AM) fungi are mutualistic symbionts that assist the plant in increasing nutrient absorption from the rhizosphere. However, the role of legume TOR in AM fungal symbiosis development has not been investigated. In this study, we examined the function of legume TOR in the development and formation of AM fungal symbiosis. RNA-interference-mediated knockdown of TOR transcripts in common bean (Phaseolus vulgaris) hairy roots notably suppressed AM fungus-induced lateral root formation by altering the expression of root meristem regulatory genes, i.e., UPB1, RGFs, and sulfur assimilation and S-phase genes. Mycorrhized PvTOR-knockdown roots had significantly more extraradical hyphae and hyphopodia than the control (empty vector) roots. Strong promoter activity of PvTOR was observed at the site of hyphal penetration and colonization. Colonization along the root length was affected in mycorrhized PvTOR-knockdown roots and the arbuscules were stunted. Furthermore, the expression of genes induced by AM symbiosis such as SWEET1, VPY, VAMP713, and STR was repressed under mycorrhized conditions in PvTOR-knockdown roots. Based on these observations, we conclude that PvTOR is a key player in regulating arbuscule development during AM symbiosis in P. vulgaris. These results provide insight into legume TOR as a potential regulatory factor influencing the symbiotic associations of P. vulgaris and other legumes.


2018 ◽  
Vol 19 (11) ◽  
pp. 3542 ◽  
Author(s):  
Ángela Prudencio ◽  
Olaf Werner ◽  
Pedro Martínez-García ◽  
Federico Dicenta ◽  
Rosa Ros ◽  
...  

DNA methylation and histone post-translational modifications have been described as epigenetic regulation mechanisms involved in developmental transitions in plants, including seasonal changes in fruit trees. In species like almond (Prunus dulcis (Mill.) D.A: Webb), prolonged exposure to cold temperatures is required for dormancy release and flowering. Aiming to identify genomic regions with differential methylation states in response to chill accumulation, we carried out Illumina reduced-representation genome sequencing on bisulfite-treated DNA from floral buds. To do this, we analyzed almond genotypes with different chilling requirements and flowering times both before and after dormancy release for two consecutive years. The study was performed using epi-Genotyping by Sequencing (epi-GBS). A total of 7317 fragments were sequenced and the samples compared. Out of these fragments, 677 were identified as differentially methylated between the almond genotypes. Mapping these fragments using the Prunus persica (L.) Batsch v.2 genome as reference provided information about coding regions linked to early and late flowering methylation markers. Additionally, the methylation state of ten gene-coding sequences was found to be linked to the dormancy release process.


2018 ◽  
Vol 1 (3) ◽  
Author(s):  
Siamak Shirani Bidabadi 1 ◽  
Majid Masoumian 2

To investigate the possible role of arbuscular mycrrhizal fungi (AMF) in alleviating the negative effects of salinity on Stevia rebaudiana (Bert.), the regenerated plantlets in tissue culture was transferred to pots in greenhouse and inoculated with Glomus intraradices. Salinity caused a significant decrease in chlorophyll content, photosynthesis efficiency and enhanced the electrolyte leakage. The use of AMF in salt –affected plants resulted in improved all above mentioned characteristics. Hydrogen peroxide and malondialdehyde (MDA) contents increased in salt stressed plants while a reduction was observed due to AMF inoculation. CAT activity showed a significant increase up to 2 g/l and then followed by decline at 5 g/l NaCl in both AMF and non-AMF treated stevia, however, AMF inoculated plants maintained lower CAT activity at all salinity levels (2 and 5 g/l). Enhanced POX activities in salt- treated stevia plants were decreased by inoculation of plants with AMF. The addition of NaCl to stevia plants also resulted in an enhanced activity of SOD whilst, AMF plants maintained higher SOD activity at all salinity levels than those of non-AMF inoculated plants. AMF inoculation was capable of alleviating the damage caused by salinity on stevia plants by reducing oxidative stress and improving photosynthesis efficiency. 


Author(s):  

Abstract A new distribution map is provided for Xylella fastidiosa Wells et al. Bacteria. Hosts: Grapevine (Vitis vinifera and others), peach (Prunus persica), Citrus, almond (Prunus dulcis), lucerne (Medicago sativa), some wild trees (including Acer rubrum, Platanus occidentalis, Quercus rubra, Ulmus americana), other wild plants and weeds. Information is given on the geographical distribution in Europe (France, Italy), Asia (Taiwan), North America (Canada (Ontario), Mexico, USA (Alabama, Arizona, Arkansas, California, Delaware, District of Columbia, Florida, Georgia, Indiana, Kentucky, Louisiana, Maryland, Mississippi, Missouri, Montana, Nebraska, New Jersey, New Mexico, New York, North Carolina, Pennsylvania, South Carolina, Tennessee, Texas, Virginia, Washington, West Virginia)), Central America and Caribbean (Costa Rica), and South America (Argentina, Brazil (Bahia, Goias, Minas Gerais, Parana, Rio de Janeiro, Rio Grande do Sul, Santa Catarina, Sao Paulo, Sergipe), Paraguay, Venezuela).


2011 ◽  
Vol 52 (No. 10) ◽  
pp. 435-440 ◽  
Author(s):  
M. Geneva ◽  
G. Zehirov ◽  
E. Djonova ◽  
N. Kaloyanova ◽  
G. Georgiev ◽  
...  

The study evaluated the response of pea (Pisum sativum cv. Avola) to arbuscular mycorrhizal fungi (AM) species Glomus mosseae and Glomus intraradices and Rhizobium leguminosarum bv. viceae, strain D 293, regarding the growth, photosynthesis, nodulation and nitrogen fixation activity. Pea plants were grown in a glasshouse until the flowering stage (35 days), in 4 kg plastic pots using leached cinnamonic forest soil (Chromic Luvisols – FAO) at P levels 13.2 (P1) and 39.8 (P2) mg P/kg soil. The obtained results demonstrated that the dual inoculation of pea plants significantly increased the plant biomass, photosynthetic rate, nodulation, and nitrogen fixation activity in comparison with single inoculation with Rhizobium leguminosarum bv. viceae strain D 293. On the other hand, coinoculation significantly increased the total phosphorus content in plant tissue, acid phosphatase activity and percentage of root colonization. The effectiveness of coinoculation with Rhizobium leguminosarum and Glomus mosseae was higher at the low phosphorus level while the coinoculation with Glomus intraradices appeared to be the most effective at higher phosphorus level.


2011 ◽  
Vol 24 (8) ◽  
pp. 867-878 ◽  
Author(s):  
Clare Gough ◽  
Julie Cullimore

The arbuscular mycorrhizal (AM) and the rhizobia-legume (RL) root endosymbioses are established as a result of signal exchange in which there is mutual recognition of diffusible signals produced by plant and microbial partners. It was discovered 20 years ago that the key symbiotic signals produced by rhizobial bacteria are lipo-chitooligosaccharides (LCO), called Nod factors. These LCO are perceived via lysin-motif (LysM) receptors and activate a signaling pathway called the common symbiotic pathway (CSP), which controls both the RL and the AM symbioses. Recent work has established that an AM fungus, Glomus intraradices, also produces LCO that activate the CSP, leading to induction of gene expression and root branching in Medicago truncatula. These Myc-LCO also stimulate mycorrhization in diverse plants. In addition, work on the nonlegume Parasponia andersonii has shown that a LysM receptor is required for both successful mycorrhization and nodulation. Together these studies show that structurally related signals and the LysM receptor family are key components of both nodulation and mycorrhization. LysM receptors are also involved in the perception of chitooligosaccharides (CO), which are derived from fungal cell walls and elicit defense responses and resistance to pathogens in diverse plants. The discovery of Myc-LCO and a LysM receptor required for the AM symbiosis, therefore, not only raises questions of how legume plants discriminate fungal and bacterial endosymbionts but also, more generally, of how plants discriminate endosymbionts from pathogenic microorganisms using structurally related LCO and CO signals and of how these perception mechanisms have evolved.


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