Metabolic aspects of plant interaction with commensal methylotrophs

Freyermuth, Sharyn K.; Long, R. L. G.; Mathur, Shalini; Holland, Mark; Holtsford, Timothy P.; Stebbins, N. E.; Morris, Roy O.; Polacco, Joseph C.

doi:10.1007/978-94-009-0213-8_37

Cited by 26 publications

(16 citation statements)

References 24 publications

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“…For example, the Methylobacterium spp. stimulate seed germination and some strains produce plant growth hormones (Holland and Polacco 1994;Freyermuth et al 1996;Holland 1997;Ivanova et al 2000;, Koenig et al 2002. According to our earlier results, pine bud endophytes produce compounds that extend viability and affect morphology of callus tissues in vitro (Pirttilä et al 2004).…”

Section: Discussionmentioning

confidence: 89%

Role of origin and endophyte infection in browning of bud-derived tissue cultures of Scots pine (Pinus sylvestris L.)

Pirttilä

Podolich

Koskimäki

et al. 2008

Plant Cell Tiss Organ Cult

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Callus tissues originating from buds of mature Scots pine (Pinus sylvestris L.) trees exhibit the typical problem of browning, which leads to degeneration and death of the tissues. The effects of medium, origin (tree and location) and endophyte infection were studied on the browning and growth of bud-derived tissue cultures. The calli growing on medium with higher kinetin content and source of organic nitrogen, and originating from the southern location grew better and exhibited less browning. Endophytic microbial cells were detected in the brown callus tissues by transmission electron microscopy. The natural endophyte infection frequency of Scots pine buds was studied and found dependent on the tree, but not on the location. A well-growing, green callus line was artificially infected by an endophytic strain of Methylobacterium extorquens, and browning was not observed on solid media compared to the uninfected control clones of the same callus. However, suspension cultures started from the infected callus died faster than cultures started from the uninfected callus. The endophyte species composition and plant genotype together with tissue culture conditions are the key factors for gaining plant tissue cultures with high regeneration capacity.

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Section: Discussionmentioning

confidence: 89%

Role of origin and endophyte infection in browning of bud-derived tissue cultures of Scots pine (Pinus sylvestris L.)

Pirttilä

Podolich

Koskimäki

et al. 2008

Plant Cell Tiss Organ Cult

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“…Leaf PPFM isolates (from Arabidopsis, barley, maize, and soybean) were obtained previously by plating ground leaves from growth chamber-grown plants onto ammonium mineral salts (AMS) minimal medium containing methanol as the sole carbon source (AMS/methanol medium), as described by Holland and Polacco (20). 16S ribosomal DNA restriction endonuclease analysis placed the isolates in the genus Methylobacterium (16). The M. extorquens type strain (ATCC 43645) was obtained from the American Type Culture Collection; this strain is a soil isolate that was described by Urakami and Komagata (45) and Bousfield and Green (5).…”

Section: Methodsmentioning

confidence: 99%

tRNA Is the Source of Low-Level trans- Zeatin Production in Methylobacterium spp

2002

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Pink-pigmented facultatively methylotrophic bacteria (PPFMs), classified as Methylobacterium spp., are persistent colonizers of plant leaf surfaces. Reports of PPFM-plant dialogue led us to examine cytokinin production by PPFMs. Using immunoaffinity and high-performance liquid chromatography (HPLC) purification, we obtained 22 to 111 ng of trans-zeatin per liter from culture filtrates of four PPFM leaf isolates (from Arabidopsis, barley, maize, and soybean) and of a Methylobacterium extorquens type culture originally recovered as a soil isolate. We identified the zeatin isolated as the trans isomer by HPLC and by a radioimmunoassay in which monoclonal antibodies specific for trans-hydroxylated cytokinins were used. Smaller and variable amounts of trans-zeatin riboside were also recovered. trans-Zeatin was recovered from tRNA hydrolysates in addition to the culture filtrates, suggesting that secreted trans-zeatin resulted from tRNA turnover rather than from de novo synthesis. The product of the miaA gene is responsible for isopentenylation of a specific adenine in some tRNAs. To confirm that the secreted zeatin originated from tRNA, we mutated the miaA gene of M. extorquens by single exchange of an internal miaA fragment into the chromosomal gene. Mutant exconjugants, confirmed by PCR, did not contain zeatin in their tRNAs and did not secrete zeatin into the medium, findings which are consistent with the hypothesis that all zeatin is tRNA derived rather than synthesized de novo. In germination studies performed with heat-treated soybean seeds, cytokinin-null (miaA) mutants stimulated germination as well as wild-type bacteria. While cytokinin production may play a role in the plant-PPFM interaction, it is not responsible for stimulation of germination by PPFMs.Although the best-studied plant-bacterium relationships involve pathogenesis or symbiosis, plants interact constantly with phylloplane bacteria and with the bacteria in the soil around their roots (rhizosphere). While it is not widely believed that epi-and endophytic bacteria have overt effects on plants, there is evidence (13) that plants interact with pink-pigmented facultatively methylotrophic bacteria (PPFMs), which are inhabitants of the phylloplane and rhizosphere. PPFMs are gram-negative members of the alpha subclass of the class Proteobacteria that belong to the genus Methylobacterium and are known to inhabit the leaf surfaces of a wide variety of plant species (11). One intriguing aspect of the plant-PPFM relationship is the possibility that PPFMs may provide cytokinins to the plant host or have cytokinin-like effects. Corpe and Basile (12) demonstrated that callus from Streptocarpus prolixus (gracilis) (Cape primrose) regenerated plantlets within 15 days when it was cultured cobiotically with PPFMs. PPFM-free controls exhibited no plant development after 30 days. However, Corpe and Basile did not indicate whether specific phytohormone regimens could mimic the PPFM effects or whether PPFMs produce phytohormones. We demonstrated previously that heat ...

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“…By producing plant growth regulators, these organisms are reported to influence seed germination and seedling growth (Dileepkumar and Dube 1992;Holland and Polacco 1992;Holland 1997;Omer et al 2004). PPFMs possess the ability to alter various physiological traits such as branching, seedling vigour, root differentiation and tolerance to heat and cold (Freyermuth et al 1996;Holland 1997). They can induce systemic resistance in plants to minimize adverse effects of pathogenic microorganisms (Madhaiyan et al 2004) and increase the photosynthetic activity in crops (Cervantes et al 2005).…”

Section: Introductionmentioning

confidence: 97%

Epiphytic pink-pigmented methylotrophic bacteria enhance germination and seedling growth of wheat (Triticum aestivum) by producing phytohormone

Meena

Kumar

Kalyuzhnaya

et al. 2011

Antonie van Leeuwenhoek

143

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Methylotrophic bacteria were isolated from the phyllosphere of different crop plants such as sugarcane, pigeonpea, mustard, potato and radish. The methylotrophic isolates were differentiated based on growth characteristics and colony morphology on methanol supplemented ammonium mineral salts medium. Amplification of the mxaF gene helped in the identification of the methylotrophic isolates as belonging to the genus Methylobacterium. Cell-free culture filtrates of these strains enhanced seed germination of wheat (Triticum aestivum) with highest values of 98.3% observed using Methylobacterium sp. (NC4). Highest values of seedling length and vigour were recorded with Methylobacterium sp. (NC28). HPLC analysis of production by bacterial strains ranged from 1.09 to 9.89 μg ml(-1) of cytokinins in the culture filtrate. Such cytokinin producing beneficial methylotrophs can be useful in developing bio-inoculants through co-inoculation of pink-pigmented facultative methylotrophs with other compatible bacterial strains, for improving plant growth and productivity, in an environment-friendly manner.

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Metabolic aspects of plant interaction with commensal methylotrophs

Cited by 26 publications

References 24 publications

Role of origin and endophyte infection in browning of bud-derived tissue cultures of Scots pine (Pinus sylvestris L.)

Role of origin and endophyte infection in browning of bud-derived tissue cultures of Scots pine (Pinus sylvestris L.)

tRNA Is the Source of Low-Level trans- Zeatin Production in Methylobacterium spp

Epiphytic pink-pigmented methylotrophic bacteria enhance germination and seedling growth of wheat (Triticum aestivum) by producing phytohormone

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