scholarly journals Suppression of Tobacco Basic Chitinase Gene Expression in Response to Colonization by the Arbuscular Mycorrhizal Fungus Glomus intraradices

1998 ◽  
Vol 11 (6) ◽  
pp. 489-497 ◽  
Author(s):  
Rakefet David ◽  
Hanan Itzhaki ◽  
Idit Ginzberg ◽  
Yedidya Gafni ◽  
Gad Galili ◽  
...  

A differentially displayed cDNA clone (MD17) was isolated from tobacco roots (Nicotiana tabacum cv. Xanthi-nc) infected with the arbuscular mycorrhizal (AM) fungus Glomus intraradices. The isolated DNA fragment exhibited a reduced level of expression in response to AM establishment and 90% identity with the 3′ noncoding sequence of two basic chitinases (EC 3.2.1.14) from N. tabacum. Northern (RNA) blots and Western blots (immunoblots), probed with tobacco basic chitinase gene-specific probe and polyclonal antibodies raised against the chitinase enzyme, yielded hybridization patterns similar to those of MD17. Moreover, the up-regulation of the 32-kDa basic chitinase gene expression in tobacco roots by (1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester (BTH) was less effective in mycorrhizal roots than in nonmycorrhizal controls. Suppression of endogenous basic chitinase (32-kDa) expression was also observed in transgenic mycorrhizal plants that constitutively express the 34-kDa basic chitinase A isoform. When plants were grown with an increased phosphate supply, no suppression of the 32-kDa basic chitinase was obtained. These findings indicate that during the colonization and establishment of G. intraradices in tobacco roots, expression of the basic chitinase gene is down-regulated at the mRNA level.

2002 ◽  
Vol 15 (4) ◽  
pp. 360-367 ◽  
Author(s):  
Juan M. Ruiz-Lozano ◽  
Carlos Collados ◽  
Rosa Porcel ◽  
Rosario Azcón ◽  
JoséM. Barea

A cDNA library was constructed with RNA from Glomus intraradices-colonized lettuce roots and used for differential screening. This allowed the identification of a cDNA (Gi-1) that was expressed only in mycorrhizal roots and was of fungal origin. The function of the gene product is unknown, because Gi-1 contained a complete open reading frame that was predicted to encode a protein of 157 amino acids which only showed little homology with glutamine synthetase from Helicobacter pylori. The time-course analysis of gene expression during the fungal life cycle showed that Gi-1 was expressed only during the mycorrhizal symbiosis and was not detected in dormant or germinating spores of G. intraradices. P fertilization did not significantly change the pattern of Gi-1 expression compared with that in the unfertilized treatment, whereas N fertilization (alone or in combination with P) considerably enhanced the Gi-1 transcript accumulation. This increase in gene expression correlated with plant N status and growth under such conditions. The possible role of the Gi-1 gene product in intermediary N metabolism of arbuscular mycorrhizal symbiosis is further discussed.


Planta ◽  
1999 ◽  
Vol 207 (4) ◽  
pp. 620-623 ◽  
Author(s):  
Walter Maier ◽  
Jürgen Schmidt ◽  
Victor Wray ◽  
Michael Herbert Walter ◽  
Dieter Strack

2006 ◽  
Vol 52 (9) ◽  
pp. 823-830 ◽  
Author(s):  
L I Stewart ◽  
S Jabaji-Hare ◽  
B T Driscoll

Specific primers were developed to amplify a 227 bp segment of the arbuscular mycorrhizal fungus Glomus intraradices gene encoding glucose-6-phosphate dehydrogenase (G6PDH), an enzyme involved in the pentose phosphate pathway. G6PDH gene expression was measured by real-time quantitative reverse transcriptase – polymerase chain reaction in response to phosphorus (P) concentrations in the growth medium of colonized transformed carrot roots. We investigated the effects of different P concentration treatments on carbon (C) metabolism within the intraradical mycelia of G. intraradices. The results showed a significant (P = 0.017) down-regulation of G6PDH expression in the intraradical mycelia of G. intraradices cultures grown in high P than low P conditions but no significant difference in regulation in excessive P concentrations when compared with the low P or high P concentrations. These results indicate that a reduction in the C flow from the host could be occurring as a result of elevated P and that a decrease in fungal G6PDH gene expression occurs, but not in the short term (less than 2 h). Reduced C flow from the host could lead to reduced fungal growth and root colonization, as was observed under high soil P conditions.Key words: arbuscular mycorrhizal fungi, phosphorus, nutrient uptake, glucose-6-phosphate dehydrogenase, gene expression.


2012 ◽  
Vol 49 (4) ◽  
pp. 313-321 ◽  
Author(s):  
Kinga A. Sędzielewska ◽  
Katja Vetter ◽  
Rüdiger Bode ◽  
Keith Baronian ◽  
Roland Watzke ◽  
...  

Agronomy ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 186 ◽  
Author(s):  
Wei-Qin Gao ◽  
Li-Hui Lü ◽  
A. Srivastava ◽  
Qiang-Sheng Wu ◽  
Kamil Kuča

A potted experiment was carried out to evaluate the effect of an arbuscular mycorrhizal fungus (AMF), Acaulospora scrobiculata, on peach seedlings grown in non-replant (NR) and replant (R) soils, to establish whether AMF inoculation alleviated soil replant disease through changes in physiological levels and relevant gene expression. After 15 weeks of mycorrhization, root mycorrhizal colonization was heavily inhibited by R treatment versus NR treatment. AMF plants under NR and R soil conditions displayed significantly higher total plant biomass than non-AMF plants. AMF inoculation significantly increased root sucrose and fructose concentrations and root catalase, peroxidase, polyphenol oxidase, and phenylalanine ammonialyase activities under R conditions. Likewise, salicylic acid, jasmonic acid, chitinase, total soluble phenol, and lignin concentrations in roots were significantly higher in AMF than in non-AMF seedlings grown in R soil. Over-expression of PpCHI, PpLOX1, PpLOX5, PpAOC3, PpAOC4, and PpOPR2 in roots was observed in AMF-inoculated seedlings, as compared to that of non-AMF-inoculated seedlings grown in R soils. Thus, mycorrhizal fungal inoculation conferred a greater tolerance to peach plants in R soil by stimulating antioxidant enzyme activities, disease-resistance substance levels, and the expression of relevant genes.


Sign in / Sign up

Export Citation Format

Share Document