Influence of an arbuscular mycorrhizal fungus on the interaction of a binucleate Rhizoctonia species with Myc+ and Myc– pea roots

Morandi, Dominique; Gollotte, Armelle; Camporota, P.

doi:10.1007/s00572-001-0154-5

Cited by 12 publications

(2 citation statements)

References 32 publications

(36 reference statements)

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“…Pisum sativum is known to possess allelopathic capabilities (Hisashi 2003) and field experiments have shown that residues and extracts of Pisum sativum suppressed the growth of several plant species (Schenk & Werner 1991; Akemo, Regnier & Bennett 2000; Hisashi 2003). At least some of the allelopathic compounds in Pisum such as pisatin, are exuded by roots (Bagga & Straney 2000; Morandi, Gollotte & Camporota 2002). In this study we did not attempt to identify the substances that are responsible for its ability to avoid obstacles.…”

Section: Discussionmentioning

confidence: 99%

Root navigation by self inhibition

Falik

Reides

Gersani

et al. 2005

Plant Cell & Environment

122

114

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Circumventing physical obstacles is critical for a plant's survival and performance. Although the ability of roots to circumvent obstacles has been known for over 100 years, the phenomena and its mechanisms have received relatively little attention. In this study it is demonstrated that roots of Pisum sativum are able to detect and avoid growth towards inanimate obstacles and the hypothesis that this behaviour is based on the sensitivity of roots to their own allelopathic exudates that accumulate in the vicinity of physical obstacles is tested. The development of lateral roots of Pisum sativum towards an obstacle (a piece of nylon string, similar in dimensions to a plant root) was followed. Lateral roots were similar in number, but significantly shorter in the direction of the nylon string. In addition, up to half of the lateral roots that developed towards the nylon string withered, whereas no withering was observed in the absence of the nylon string. These avoidance growth patterns were suppressed in the presence of potassium permanganate or activated carbon, indicating a role of allelopathic exudates in promoting obstacle avoidance. The demonstrated obstacle avoidance by self inhibition could increase plant performance by limiting resource allocation to less promising parts of the root system.

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Section: Discussionmentioning

confidence: 99%

Root navigation by self inhibition

Falik

Reides

Gersani

et al. 2005

Plant Cell & Environment

122

114

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“…These results provide new insights on the characterization of this DMI3 M. truncatula mutant that is unable to develop mycorrhiza and nodule symbioses (Sagan et al, 1995;Catoira et al, 2000). It has been reported to be infected by a root pathogenic fungus (Morandi et al, 2002), and its phenotype can now also be termed ''Pseu 1 ,'' which pleads in favor of the terminology MtSYM13 rather than DMI3 to describe the corresponding plant gene (Morandi et al, 2004).…”

Section: Comparison Of Plant Gene Expression Profiles In G Mosseae-amentioning

confidence: 99%

Pseudomonas fluorescens and Glomus mosseae Trigger DMI3-Dependent Activation of Genes Related to a Signal Transduction Pathway in Roots of Medicago truncatula

et al. 2005

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Plant genes induced during early root colonization of Medicago truncatula Gaertn. J5 by a growth-promoting strain of Pseudomonas fluorescens (C7R12) have been identified by suppressive subtractive hybridization. Ten M. truncatula genes, coding proteins associated with a putative signal transduction pathway, showed an early and transient activation during initial interactions between M. truncatula and P. fluorescens, up to 8 d after root inoculation. Gene expression was not significantly enhanced, except for one gene, in P. fluorescens-inoculated roots of a Myc Nod2 genotype (TRV25) of M. truncatula mutated for the DMI3 (syn. MtSYM13) gene. This gene codes a Ca 21 and calmodulin-dependent protein kinase, indicating a possible role of calcium in the cellular interactions between M. truncatula and P. fluorescens. When expression of the 10 plant genes was compared in early stages of root colonization by mycorrhizal and rhizobial microsymbionts, Glomus mosseae activated all 10 genes, whereas Sinorhizobium meliloti only activated one and inhibited four others. None of the genes responded to inoculation by either microsymbiont in roots of the TRV25 mutant. The similar response of the M. truncatula genes to P. fluorescens and G. mosseae points to common molecular pathways in the perception of the microbial signals by plant roots.Root exudates play an active role in the regulation of symbiotic and pathogenic interactions with microbes (Hirsch et al., 2003). Rhizosphere microorganisms in turn can have a decisive influence on plant health. The most commonly studied beneficial interactions are the arbuscular mycorrhizal (AM) symbiosis, between the majority of land plant families and fungi in the phylum Glomeromycota (Smith and Read, 1997;Schü ssler et al., 2001), and the nodule symbiosis restricted to legumes and bacteria of the family Rhizobiaceae (Dénarié et al., 1992;Franssen et al., 1992;Perret et al., 2000). Several other genera of soil bacteria, including Pseudomonas and Bacillus species, can stimulate root proliferation or have antagonistic effects on pathogens in the rhizosphere (Kloepper and Schroth, 1978;Ellis et al., 2000;Whipps, 2001). Contrary to the AM and nodule symbioses, few investigations have focused on the molecular bases of plant responses to rhizobacteria such as Pseudomonas, and studies have mainly been concerned with elucidating the basis of induced systemic resistance by Pseudomonas species in Arabidopsis (Arabidopsis thaliana; Cartieaux et al., Verhagen et al., 2004;Wang et al., 2005).The lack of information about plant gene expression during root colonization by Pseudomonas fluorescens prompted us to exploit suppressive subtractive hybridization (SSH; Diatchenko et al., 1996) to identify plant gene responses during early-stage colonization of Medicago truncatula Gaertn. roots by P. fluorescens strain C7R12. P. fluorescens strain C7R12 is a spontaneous rifampicin-resistant mutant of a wild-type strain C7 (Eparvier et al., 1991) previously isolated from the rhizosphere of flax cultivated in a soil ...

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Evaluation of arbuscular mycorrhiza with symbiotic and nonsymbiotic pea isolines at three sites in the Alentejo, Portugal

Kleikamp

Joergensen

2006

Z. Pflanzenernähr. Bodenk.

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Providing an appropriate negative control for the experimental factor arbuscular mycorrhiza (AM) is a fundamental methodological problem. Therefore, the nonmycorrhizal (myc –) and nonnodulating (nod –) pea (Pisum sativum L.) mutant P2 was studied together with the parental symbiotic isogenetic variety Frisson in three experiments: (1) growth response to water supply in a climate chamber under nonsymbiotic growth conditions, (2) field evaluation at three sites in the Alentejo, South Portugal, and (3) growth response to P supply in a soil low in available P in a greenhouse‐chamber experiment. In the climate chamber at high NPK levels, mutant P2 achieved the same biomass as Frisson at 80% and 40% water‐holding capacity, respectively. For the field evaluation, three sites were chosen with normal arable use (Évora), extensive use as Montado (Portel), and intensive horticultural use (Mitra). The colonization of pea roots with AM fungi ranged from 4% (Mitra) to more than 90% (Portel), probably caused by differences in P availability. The plant density of mutant P2 was generally 25% lower than that of Frisson. Yield indices were all lowest at Portel, despite the same NPK fertilization. Grain and shoot yield of mutant P2 did not reach the level of Frisson at any site. Differences in N and P concentrations between the two isolines were insignificant in most cases. Differences in the amount of shoot P per plant consistently mirrored the mycorrhizal status of the three sites. Roughly 50% of the yield depression per m2 could be attributed to the lower plant density of mutant P2, the remaining 50% must be caused by AM‐fungal colonization or other factors. In the final pot experiment using the soil with low P availability from Portel, the main benefit of AM for peas was enhanced P uptake. Central questions could not be answered using a nonmycorrhizal control. However, mutants remain one interesting tool, best be used in combination with other approaches to estimate the effects of mycorrhization.

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Influence of an arbuscular mycorrhizal fungus on the interaction of a binucleate Rhizoctonia species with Myc+ and Myc– pea roots

Cited by 12 publications

References 32 publications

Root navigation by self inhibition

Root navigation by self inhibition

Pseudomonas fluorescens and Glomus mosseae Trigger DMI3-Dependent Activation of Genes Related to a Signal Transduction Pathway in Roots of Medicago truncatula

Evaluation of arbuscular mycorrhiza with symbiotic and nonsymbiotic pea isolines at three sites in the Alentejo, Portugal

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