Genetic and Cellular Analysis of Resistance to Vesicular Arbuscular (VA) Mycorrhizal Fungi in Pea Mutants

Gianinazzi‐Pearson, Vivienne; Gianinazzi, Silvio; Guillemin, J. P.; Trouvelot, A.; Duc, Gérard

doi:10.1007/978-94-015-7934-6_52

Cited by 79 publications

(64 citation statements)

References 6 publications

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“…Our data indicate that all dnf mutants permit the initial nodulation events involved in the establishment of the nodule primordium and nodule and cellular infection by the bacteria (data not shown). Additionally, all dnf mutants are able to support a normal endomycorrhizal symbiosis (M. Harrison, personal communication) unlike some P. sativum Fix 2 mutants (Gianinazzi-Pearson et al, 1991). Because the dnf mutants show no obvious nonsymbiotic defects in growth, fecundity, or size and shape when supplemented with nitrogen-containing fertilizers (data not shown), we speculate that the DNF genes are required specifically for symbiotic nitrogen fixation.…”

Section: Discussionmentioning

confidence: 89%

Nitrogen Fixation Mutants ofMedicago truncatulaFail to Support Plant and Bacterial Symbiotic Gene Expression

et al. 2006

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The Rhizobium-legume symbiosis culminates in the exchange of nutrients in the root nodule. Bacteria within the nodule reduce molecular nitrogen for plant use and plants provide bacteria with carbon-containing compounds. Following the initial signaling events that lead to plant infection, little is known about the plant requirements for establishment and maintenance of the symbiosis. We screened 44,000 M2 plants from fast neutron-irradiated Medicago truncatula seeds and isolated eight independent mutant lines that are defective in nitrogen fixation. The eight mutants are monogenic and represent seven complementation groups. To monitor bacterial status in mutant nodules, we assayed Sinorhizobium meliloti symbiosis gene promoters (nodF, exoY, bacA, and nifH) in the defective in nitrogen fixation mutants. Additionally, we used an Affymetrix oligonucleotide microarray to monitor gene expression changes in wild-type and three mutant plants during the nodulation process. These analyses suggest the mutants can be separated into three classes: one class that supports little to no nitrogen fixation and minimal bacterial expression of nifH; another class that supports no nitrogen fixation and minimal bacterial expression of nodF, bacA, and nifH; and a final class that supports low levels of both nitrogen fixation and bacterial nifH expression.

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Section: Discussionmentioning

confidence: 89%

Nitrogen Fixation Mutants ofMedicago truncatulaFail to Support Plant and Bacterial Symbiotic Gene Expression

et al. 2006

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“…In only one case (sym36) does a mutant link the cortical program of nodulation with AM development. As mentioned earlier, sym36 has abnormal IT and few dividing inner cortical cells (Sagan et al 1994); upon fungal colonization, it forms stumpy arbuscules (Gianinazzi-Pearson et al 1991). The fungal hypha enters the cortical cell and differentiates into an arbuscular trunk, but no branches form.…”

Section: Epidermismentioning

confidence: 85%

A model for the development of the rhizobial and arbuscular mycorrhizal symbioses in legumes and its use to understand the roles of ethylene in the establishment of these two symbioses

Guinel¹,

Geil²

2002

Can. J. Bot.

157

103

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We propose a model depicting the development of nodulation and arbuscular mycorrhizae. Both processes are dissected into many steps, using Pisum sativum L. nodulation mutants as a guideline. For nodulation, we distinguish two main developmental programs, one epidermal and one cortical. Whereas Nod factors alone affect the cortical program, bacteria are required to trigger the epidermal events. We propose that the two programs of the rhizobial symbiosis evolved separately and that, over time, they came to function together. The distinction between these two programs does not exist for arbuscular mycorrhizae development despite events occurring in both root tissues. Mutations that affect both symbioses are restricted to the epidermal program. We propose here sites of action and potential roles for ethylene during the formation of the two symbioses with a specific hypothesis for nodule organogenesis. Assuming the epidermis does not make ethylene, the microsymbionts probably first encounter a regulatory level of ethylene at the epidermis outermost cortical cell layer interface. Depending on the hormone concentrations there, infection will either progress or be blocked. In the former case, ethylene affects the cortex cytoskeleton, allowing reorganization that facilitates infection; in the latter case, ethylene acts on several enzymes that interfere with infection thread growth, causing it to abort. Throughout this review, the difficulty of generalizing the roles of ethylene is emphasized and numerous examples are given to demonstrate the diversity that exists in plants.Key words: AM, epidermis, evolution, pea, rhizobia, sym mutant.

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“…In the resulting mutants, expression of the VA mycorrhiza resistance character (myc-) is always associated with that of a non-nodulating phenotype (nod"), suggesting that common plant genes may control some early step(s) in the infection processes of the two types of root symbiosis. The genetical resistance mutants is characterized by an infection in which is, in most mutants, restricted to abortive entry points and where root cells adjacent to infecting hyphae produce an important deposit of wall material (Gianinazzi-Pearson et al, 1991). Such structural modifications are accompanied by changes in the protein composition of mutant roots which differ from those occurring in a mycorrhizal (myc"*^) host root (L. Schellenbaum, personal communication).…”

Section: Discussionmentioning

confidence: 99%

Influence of intergeneric grafts between host and non‐host legumes on formation of vesicular–arbuscular mycorrhiza

Gianinazzi‐Pearson

Gianinazzi

1992

New Phytologist

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SUMMARYStem grafts were carried out between different varieties of vesicular-arbuscular (VA) mycorrhizal host (pea, soybean) and non-host (lupin) legumes. Only grafts on host rootstock were successful. Self-grafts of three pea varieties (Amino, Solara, Frisson), and interspecific grafts between soyhean (var. Amsoy 71) and pea (var. Frisson), did not generally affect development of, or arbuscule formation hy, Glomus intraradices Schenck & Smith or G. mosseae Nicol. & Gerd. within the rootstock. In contrast, lupin (var. Alban and Lucky) scions greatly reduced colonization of the root cortex and completely inhibited arhuscule formation hy both fungi in grafted pea rootstock. The possible role of mobile shoot factors in non-host resistance to VA mycorrhizal fungi in lupins is discussed.

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Genetic and Cellular Analysis of Resistance to Vesicular Arbuscular (VA) Mycorrhizal Fungi in Pea Mutants

Cited by 79 publications

References 6 publications

Nitrogen Fixation Mutants ofMedicago truncatulaFail to Support Plant and Bacterial Symbiotic Gene Expression

Nitrogen Fixation Mutants ofMedicago truncatulaFail to Support Plant and Bacterial Symbiotic Gene Expression

A model for the development of the rhizobial and arbuscular mycorrhizal symbioses in legumes and its use to understand the roles of ethylene in the establishment of these two symbioses

Influence of intergeneric grafts between host and non‐host legumes on formation of vesicular–arbuscular mycorrhiza

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