Article

Symbiosis-related pea genes modulate fungal and plant gene expression during the arbuscule stage of mycorrhiza with Glomus intraradices.

UMR 1088 INRA/5184 CNRS/Université de Bourgogne Plante-Microbe-Environnement, INRA-CMSE, 21065 Dijon Cedex, France.
Mycorrhiza (Impact Factor: 2.99). 08/2010; 20(6):427-43. DOI: 10.1007/s00572-009-0292-8
Source: PubMed

ABSTRACT The arbuscular mycorrhiza association results from a successful interaction between genomes of the plant and fungal symbiotic partners. In this study, we analyzed the effect of inactivation of late-stage symbiosis-related pea genes on symbiosis-associated fungal and plant molecular responses in order to gain insight into their role in the functional mycorrhizal association. The expression of a subset of ten fungal and eight plant genes, previously reported to be activated during mycorrhiza development, was compared in Glomus intraradices-inoculated wild-type and isogenic genotypes of pea mutated for the PsSym36, PsSym33, and PsSym40 genes where arbuscule formation is inhibited or fungal turnover modulated, respectively. Microdissection was used to corroborate arbuscule-related fungal gene expression. Molecular responses varied between pea genotypes and with fungal development. Most of the fungal genes were downregulated when arbuscule formation was defective, and several were upregulated with more rapid fungal development. Some of the plant genes were also affected by inactivation of the PsSym36, PsSym33, and PsSym40 loci, but in a more time-dependent way during root colonization by G. intraradices. Results indicate a role of the late-stage symbiosis-related pea genes not only in mycorrhiza development but also in the symbiotic functioning of arbuscule-containing cells.

0 Bookmarks
 · 
130 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background and AimsArbuscular mycorrhizal symbioses are important for nutrient acquisition in >80 % of terrestrial plants. Recently there have been major breakthroughs in understanding the signals that regulate colonization by the fungus, but the roles of the known plant hormones are still emerging. Here our understanding of the roles of abscisic acid, ethylene, auxin, strigolactones, salicylic acid and jasmonic acid is discussed, and the roles of gibberellins and brassinosteroids examined.Methods Pea mutants deficient in gibberellins, DELLA proteins and brassinosteroids are used to determine whether fungal colonization is altered by the level of these hormones or signalling compounds. Expression of genes activated during mycorrhizal colonization is also monitored.Key ResultsArbuscular mycorrhizal colonization of pea roots is substantially increased in gibberellin-deficient na-1 mutants compared with wild-type plants. This is reversed by application of GA3. Mutant la cry-s, which lacks gibberellin signalling DELLA proteins, shows reduced colonization. These changes were parallelled by changes in the expression of genes associated with mycorrhizal colonization. The brassinosteroid-deficient lkb mutant showed no change in colonization.Conclusions Biologically active gibberellins suppress arbuscule formation in pea roots, and DELLA proteins are essential for this response, indicating that this role occurs within the root cells.
    Annals of Botany 03/2013; · 3.45 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: One important function of the arbuscular mycorrhizal (AM) symbiosis is the protection of plants against pathogenic microorganisms, but little is known of the molecular background of mycorrhiza-induced resistance (MIR) in roots. Here, we investigated possible mechanisms responsible for reduced disease development in Funneliformis mosseae–colonized roots of Petunia hybrida after infection with the root rot pathogen Thielaviopsis basicola. Monitoring of the pathogenic fungus revealed that reduced symptoms in mycorrhizal root systems are not primarily based on increased disease tolerance, but rather on induced resistance. The presence of T. basicola did not affect mycorrhiza development immediately (24 and 36 hours after pathogen inoculation) but showed a slight negative influence after one week. AM induction of P. hybrida genes coding for nutrient transporters and defence-related genes was reduced by pathogen infection for some, but not all and only transiently, indicating that mycorrhiza functioning was maintained on the whole in pathogen-infected roots. In transcript profiling of 15 defence-related plant genes partially regulated by salicylic acid (SA) or jasmonate (JA) pathways, none showed expression resembling the phenomenon of priming usually accompanying JA-induced systemic resistance; several SA-regulated genes were down-regulated, when mycorrhizal roots were challenged with the pathogen. It is therefore proposed that mycorrhiza-intrinsic plant defence responses could establish a local barrier against root pathogens in mycorrhizal tissues. Expression patterns indicated a role of a basic endochitinase in these mycorrhiza-preformed barriers. Moreover, results suggested other oxilipins than jasmonate could be involved in signalling during interactions between the AM fungus and the pathogen in roots.
    Physiological and Molecular Plant Pathology 10/2014; · 1.98 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Anthracnose is the most severe post-harvest disease of many cultivars of avocado. Identification of avocado genes involved in the defence response against Colletotrichum gloeosporioides is a crucial step towards understanding the molecular basis of resistance in avocado fruit. Following 454 sequencing and analysis of the transcriptome of Fuerte avocado fruits infected with C. gloeosporioides, quantitative real-time PCR was employed to measure the expression of some candidate resistance and defence-related genes expressed during anthracnose disease. The selected genes included those coding for the endogenous control genes (actin and glyceraldehyde 3-phosphate dehydrogenase), salicylic acid binding protein 2 (SABP2), ethylene responsive element binding protein (EREBP), leucine rich protein (LRR), catalase, endochitinase, endo-1,4-D-glucanase and pathogenesis related proteins 5 (PR 5) and 6 (PR 6). The study identified many genes involved in key components of the resistance response including recognition, signalling, transcription, the oxidative burst, PR protein induction, R genes and the hypersensitive response. Expression profiles showed that selected genes were differentially expressed after infection when compared to the uninfected sample but that there is a modulation of the defence response, suggestive of a compatible-type interaction. This transcriptome analysis provides a first elucidation of the molecular networks involved in the resistance of avocado fruit to fungal parasitic infection and provides an important contribution to functional genomic approaches to understanding resistance in non-model crop plants.
    South African Journal of Botany 05/2013; 86:92–100. · 1.34 Impact Factor

Full-text (2 Sources)

Download
9 Downloads
Available from
Oct 14, 2014