Sucrose metabolism during Agrobacterium tumefaciens — induced tumor growth in sunflower hypocotyls

Kutschera, U.; Bahrami, Masoud; Grotha, Rüdiger

doi:10.1016/s0176-1617(00)80262-x

Cited by 2 publications

(1 citation statement)

References 20 publications

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“…Based on the Ribosomal Database Project (small-subunit [16S] rRNA sequences) it became apparent that most epiphytic bacteria belong to the subdivision of Alpha-Proteobacteria (genera Rhizobium, Agrobacterium, Methylobacterium, etc.). These primarily free-living "purple bacteria" can form symbiotic relationships (rhizobia as nitrogen-fixing microbes in the root nodules of legumes 11 ), act as plant pathogens (agrobacteria that induce crown-gall tumors 12 ) or live as leaf-associated commensals/beneficial partners of the plant (methylobacteria as phytosymbionts 3 ). It should be noted that some obligate intracellular parasites of animals and humans that can cause typhus (microbes of the genus Rickettsia) are also members of the Alpha-subclass of Proteobacteria.…”

Section: Free-living Proteobacteria Mitochondria and The Genus Methymentioning

confidence: 99%

Plant-Associated Methylobacteria as Co-Evolved Phytosymbionts

Kutschera

2007

Plant Signaling & Behavior

113

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Due to their wall-associated pectin metabolism, growing plant cells emit significant amounts of the one-carbon alcohol methanol. Pink-pigmented microbes of the genus Methylobacterium that colonize the surfaces of leaves (epiphytes) are capable of growth on this volatile C1-compound as sole source of carbon and energy. In this article the results of experiments with germ-free (gnotobiotic) sporophytes of angiosperms (sunflower, maize) and gametophytes of bryophytes (a moss and two liverwort species) are summarized. The data show that methylobacteria do not stimulate the growth of these angiosperms, but organ development in moss protonemata and in thalli of liverworts is considerably enhanced. Since methylobacteria produce and secrete cytokinins and auxin, a model of plant-microbe-interaction (symbiosis) is proposed in which the methanol-consuming bacteria are viewed as coevolved partners of the gametophyte that determine its growth, survival and reproduction (fitness). This symbiosis is restricted to the haploid cells of moisture-dependent "living fossil" plants; it does not apply to the diploid sporophytes of higher embryophytes, which are fully adapted to life on land and apparently produce sufficient amounts of endogenous phytohormones.

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Section: Free-living Proteobacteria Mitochondria and The Genus Methymentioning

confidence: 99%

Plant-Associated Methylobacteria as Co-Evolved Phytosymbionts

Kutschera

2007

Plant Signaling & Behavior

113

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Vascularization, High-Volume Solution Flow, and Localized Roles for Enzymes of Sucrose Metabolism during Tumorigenesis byAgrobacterium tumefaciens

et al. 2003

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Vascular differentiation and epidermal disruption are associated with establishment of tumors induced by Agrobacterium tumefaciens. Here, we address the relationship of these processes to the redirection of nutrient-bearing water flow and carbohydrate delivery for tumor growth within the castor bean (Ricinus communis) host. Treatment with aminoethoxyvinylglycine showed that vascular differentiation and epidermal disruption were central to ethylene-dependent tumor establishment. CO 2 release paralleled tumor growth, but water flow increased dramatically during the first 3 weeks. However, tumor water loss contributed little to water flow to host shoots. Tumor water loss was followed by accumulation of the osmoprotectants, sucrose (Suc) and proline, in the tumor periphery, shifting hexose-to-Suc balance in favor of sugar signals for maturation and desiccation tolerance. Concurrent activities and sites of action for enzymes of Suc metabolism changed: Vacuolar invertase predominated during initial import of Suc into the symplastic continuum, corresponding to hexose concentrations in expanding tumors. Later, Suc synthase (SuSy) and cell wall invertase rose in the tumor periphery to modulate both Suc accumulation and descending turgor for import by metabolization. Sites of abscisic acid immunolocalization correlated with both central vacuolar invertase and peripheral cell wall invertase. Vascular roles were indicated by SuSy immunolocalization in xylem parenchyma for inorganic nutrient uptake and in phloem, where resolution allowed SuSy identification in sieve elements and companion cells, which has widespread implications for SuSy function in transport. Together, data indicate key roles for ethylene-dependent vascularization and cuticular disruption in the redirection of water flow and carbohydrate transport for successful tumor establishment.

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Sucrose metabolism during Agrobacterium tumefaciens — induced tumor growth in sunflower hypocotyls

Cited by 2 publications

References 20 publications

Plant-Associated Methylobacteria as Co-Evolved Phytosymbionts

Plant-Associated Methylobacteria as Co-Evolved Phytosymbionts

Vascularization, High-Volume Solution Flow, and Localized Roles for Enzymes of Sucrose Metabolism during Tumorigenesis byAgrobacterium tumefaciens

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