Responses of the Plant to Nod Factors

Hadri, Az-Eddine; Bisseling, Ton

doi:10.1007/978-94-011-5060-6_21

Cited by 30 publications

(23 citation statements)

References 71 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The key event in nodule formation is the synthesis and release by the bacteria of small molecules that are detected by the plant and that trigger formation of the nodule (95,119,163,188,302). These molecules are called Nod factors (also known as lipo-chito-oligosaccharides).…”

Section: Host Detection During Nodule Formationmentioning

confidence: 99%

“…Detection of Nod factors by a legume host induces major developmental changes in VOL. 69,2005 HOST DETECTION BY PLANT-ASSOCIATED BACTERIA 159 the plant, which are required for entry of the rhizobia into the host (120,163,188,470). The tip of a root hair, to which rhizobia are bound, curls back on itself, trapping the bacteria within a pocket, from which they are taken up into a plantmade intracellular-infection thread.…”

Section: Host Detection During Nodule Formationmentioning

confidence: 99%

See 1 more Smart Citation

Detection of and Response to Signals Involved in Host-Microbe Interactions by Plant-Associated Bacteria

Brencic

Winans

2005

Microbiol Mol Biol Rev

337

208

View full text Add to dashboard Cite

Diverse interactions between hosts and microbes are initiated by the detection of host-released chemical signals. Detection of these signals leads to altered patterns of gene expression that culminate in specific and adaptive changes in bacterial physiology that are required for these associations. This concept was first demonstrated for the members of the family Rhizobiaceae and was later found to apply to many other plant-associated bacteria as well as to microbes that colonize human and animal hosts. The family Rhizobiaceae includes various genera of rhizobia as well as species of Agrobacterium. Rhizobia are symbionts of legumes, which fix nitrogen within root nodules, while Agrobacterium tumefaciens is a pathogen that causes crown gall tumors on a wide variety of plants. The plant-released signals that are recognized by these bacteria are low-molecular-weight, diffusible molecules and are detected by the bacteria through specific receptor proteins. Similar phenomena are observed with other plant pathogens, including Pseudomonas syringae, Ralstonia solanacearum, and Erwinia spp., although here the signals and signal receptors are not as well defined. In some cases, nutritional conditions such as iron limitation or the lack of nitrogen sources seem to provide a significant cue. While much has been learned about the process of host detection over the past 20 years, our knowledge is far from being complete. The complex nature of the plant-microbe interactions makes it extremely challenging to gain a comprehensive picture of host detection in natural environments, and thus many signals and signal recognition systems remain to be described

show abstract

Section: Host Detection During Nodule Formationmentioning

confidence: 99%

Section: Host Detection During Nodule Formationmentioning

confidence: 99%

Detection of and Response to Signals Involved in Host-Microbe Interactions by Plant-Associated Bacteria

Brencic

Winans

2005

Microbiol Mol Biol Rev

337

208

View full text Add to dashboard Cite

show abstract

“…Readers are referred to Brewin (1991Brewin ( , 1998, Hirsch (1992), and Hadri and Bisseling (1998) for extensive reviews of nodule organogenesis and Peterson and Farquhar (1994), Bonfante and Perotto (1995), and Harrison (1999) for mycorrhizae formation. The use of mutants has allowed researchers to dissect in detail the morphogenesis of the symbiotic structures, unraveling new steps in the process.…”

Section: Mutualistic Symbiosesmentioning

confidence: 99%

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

View full text Add to dashboard Cite

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.

show abstract

“…It dwells in the soil and, on its host plant, elicits the formation of root nodules through a complex interaction between the two partners. Specific lipochitooligosaccharides produced by rhizobia, called Nod factors, have been well documented for many rhizobial species, including M. loti; these compounds trigger root-hair curling and nodule organogenesis in a host-specific manner (Hadri & Bisseling, 1998;Niwa et al, 2001). Rhizobia colonize the curled root hairs and invade the developing nodules via infection threads (ITs), which are formed by invagination of the root-hair cell membrane.…”

Section: Introductionmentioning

confidence: 99%

A Mesorhizobium loti mutant with reduced glucan content shows defective invasion of its host plant Lotus japonicus

et al. 2007

View full text Add to dashboard Cite

Random transposon mutagenesis led to the isolation of a novel Mesorhizobium loti mutant that is defective in nitrogen fixation during symbiosis with Lotus japonicus. The mutated locus, designated cep, encodes a putative cell-envelope protein displaying no significant sequence similarity to proteins with known functions. This mutant elicits the formation of nodule-like bumps and root-hair curling, but not the elongation of infection threads, on L. japonicus roots. This is reminiscent of the phenotypes of rhizobial mutants impaired in cyclic b-glucan biosynthesis. The cep mutant exhibits partially reduced content of cell-associated glucans and intermediate deficiency of motility under hypo-osmotic conditions as compared to a glucan-deficient mutant. Second-site pseudorevertants of the cep mutant were isolated by selecting for restoration of symbiotic nitrogen fixation. A subset of pseudorevertants restored both symbiotic capability and glucan content to levels comparable to that of the wild-type. These results suggest that the Cep product acts on a successful symbiosis by affecting cell-associated glucan content. INTRODUCTIONMesorhizobium loti is a symbiotic partner of Lotus japonicus, a model legume widely used for molecular genetic studies. It dwells in the soil and, on its host plant, elicits the formation of root nodules through a complex interaction between the two partners. Specific lipochitooligosaccharides produced by rhizobia, called Nod factors, have been well documented for many rhizobial species, including M. loti; these compounds trigger root-hair curling and nodule organogenesis in a host-specific manner (Hadri & Bisseling, 1998;Niwa et al., 2001). Rhizobia colonize the curled root hairs and invade the developing nodules via infection threads (ITs), which are formed by invagination of the root-hair cell membrane. Rhizobial cells are finally released into the host nodule cells, where they carry out symbiotic nitrogen fixation. The specificity between rhizobia and host legumes is also exhibited at stages later than those at which Nod factors act. This is exemplified in the symbiotic phenotype of Rhizobium etli on L. japonicus, in which early nodule senescence occurs despite the fact that the Nod factors from M. loti and R. etli have the same structure (Banba et al., 2001). To fully understand the molecular basis for the interaction between the model symbiotic pair M. loti and L. japonicus, additional symbiotic genes need to be identified extensively in the M. loti genome.In rhizobia, the cell envelope should first come to the bacterium-plant interface and mediate communication with the host through attachment or signal exchange. Also, the cell envelope contains essential machinery for nutrient uptake and electron transport, some components of which play specific roles in symbiosis (Delgado et al., 1998;Lodwig & Poole, 2003). As constituents of the cell envelope, cell-surface carbohydrates such as lipopolysaccharides, extracellular polysaccharides, capsular polysaccharides and cyclic b-glucans are known...

show abstract

Responses of the Plant to Nod Factors

Cited by 30 publications

References 71 publications

Detection of and Response to Signals Involved in Host-Microbe Interactions by Plant-Associated Bacteria

Detection of and Response to Signals Involved in Host-Microbe Interactions by Plant-Associated Bacteria

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

A Mesorhizobium loti mutant with reduced glucan content shows defective invasion of its host plant Lotus japonicus

Contact Info

Product

Resources

About