Nodule Morphogenesis and Differentiation

Newcomb, William W.

doi:10.1016/b978-0-12-364374-2.50018-5

Cited by 98 publications

(100 citation statements)

References 78 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The shape of a nodule depends on the location and the period of activity of its meristem. In indeterminate nodules, the lengthy activity (several weeks) of the apical meristem is responsible for the elongation of the nodules (14,24,41). In S. rostrata root nodules, the activity of the peripheral meristem, restricted to a shorter period of time following inoculation, accounts for the uniform enlargement of the nodules, with the infected tissue surrounding the initial infection site.…”

Section: Discussionmentioning

confidence: 99%

“…In tropical legumes, the nodule meristem is induced in the outer cortex, and the bacteria are released into actively dividing meristematic cells, each daughter cell receiving rhizobia (24,26). Meristematic activity is restricted to a short period of time and, following a round of successive divisions, the invaded meristematic cells differentiate simultaneously to form the nitrogen-fixing central tissue (24). As a result of this developmental pathway, nodule growth and functioning are dissociated.…”

mentioning

confidence: 99%

“…The persistent activity of the meristem, located at the outer extremity of the nodule, ensures nodule elongation for a number of weeks (41). While the meristem is active, rhizobia are released from the infection threads into the plant cell cytoplasm (5,14,17,24). The differentiation of both symbionts leads to the establishment of a central zone of the nodule, in which nitrogen is reduced (22,41).…”

mentioning

confidence: 99%

“…In other tropical legumes, such as Glycine max (26,39), the infection process proceeds as in temperate legumes, i.e., by the formation of infection threads through root hairs. In tropical legumes, the nodule meristem is induced in the outer cortex, and the bacteria are released into actively dividing meristematic cells, each daughter cell receiving rhizobia (24,26). Meristematic activity is restricted to a short period of time and, following a round of successive divisions, the invaded meristematic cells differentiate simultaneously to form the nitrogen-fixing central tissue (24).…”

mentioning

confidence: 99%

“…There are two main types of nodule development, the so-called indeterminate and determinate types (5,14,22,24). Indeterminate nodules generally develop on temperate legumes, such as alfalfa, vetch, or pea.…”

mentioning

confidence: 99%

See 4 more Smart Citations

Root nodulation of Sesbania rostrata

et al. 1994

View full text Add to dashboard Cite

The tropical legume Sesbania rostrata can be nodulated by Azorhizobium caulinodans on both its stem and its root system. Here we investigate in detail the process of root nodulation and show that nodules develop exclusively at the base of secondary roots. Intercellular infection leads to the formation of infection pockets, which then give rise to infection threads. Concomitantly with infection, cortical cells of the secondary roots dedifferentiate, forming a meristem which has an "open-basket" configuration and which surrounds the initial infection site. Bacteria are released from the tips of infection threads into plant cells via "infection droplets," each containing several bacteria. Initially, nodule differentiation is comparable to that of indeterminate nodules, with the youngest meristematic cells being located at the periphery and the nitrogen-fixing cells being located at the nodule center. Because of the peculiar form of the meristem, Sesbania root nodules develop uniformly around a central axis. Nitrogen fixation is detected as early as 3 days following inoculation, while the nodule meristem is still active. Two weeks after inoculation, meristematic activity ceases, and nodules then show the typical histology of determinate nodules. Thus, root nodule organogenesis in S. rostrata appears to be intermediate between indeterminate and determinate types.

show abstract

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Root nodulation of Sesbania rostrata

et al. 1994

View full text Add to dashboard Cite

show abstract

Organization and ultrastructure of Medicago truncatula root nodule meristem

Skawińska¹,

Sańko-Sawczenko²,

Czarnocka³

et al. 2019

The Model Legume Medicago Truncatula

View full text Add to dashboard Cite

The early nodulin transcript ENOD2 is located in the nodule parenchyma (inner cortex) of pea and soybean root nodules.

et al. 1990

View full text Add to dashboard Cite

A pea cDNA clone homologous to the soybean early nodulin clone pGmENOD2 that most probably encodes a cell wall protein was isolated. The derived amino acid sequence of the pea ENOD2 protein shows that it contains the same repeating pentapeptides, ProProHisGluLys and ProProGluTyrGln, as the soybean ENOD2 protein. By in situ hybridization the expression of the ENOD2 gene was shown to occur only in the inner cortex of the indeterminate pea nodule. The transcription of the pea ENOD2 gene starts when the inner cortical cells develop from the nodule meristem. In the determinate soybean nodule the ENOD2 gene is expressed in the inner cortex as well as in cells surrounding the vascular bundle that connects the nodule with the root central cylinder. The term ‘nodule inner cortex’ is misleading, as there is no direct homology with the root inner cortex. Therefore, we propose to consider this tissue as nodule parenchyma. A possible role of ENOD2 in a major function of the nodule parenchyma, namely creating an oxygen barrier for the central tissue with the Rhizobium containing cells, is discussed.

show abstract

Nodule Morphogenesis and Differentiation

Cited by 98 publications

References 78 publications

Root nodulation of Sesbania rostrata

Root nodulation of Sesbania rostrata

Organization and ultrastructure of Medicago truncatula root nodule meristem

The early nodulin transcript ENOD2 is located in the nodule parenchyma (inner cortex) of pea and soybean root nodules.

Contact Info

Product

Resources

About