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The dynamics of apoplast phenolics in tobacco leaves following inoculation with bacteria.

Baker CJ, Mock NM, Smith JM, Aver'yanov AA - Front Plant Sci (2015)

Bottom Line: The patterns of phenolic change in the apoplast were compared for tobacco inoculated with P. syringae pathovars, pv. syringae, which causes a resistant HR reaction within 15 h, and pv. tabaci, which causes a susceptible reaction with delayed visible symptoms.Both pathogens elicited lower increased levels of acetosyringone compared to the saprophyte, P. fluorescens but had greatly increased levels of the chlorogenic acid derivatives.This unexpected aspect will require further study of intracellular phenolics.

View Article: PubMed Central - PubMed

Affiliation: Molecular Plant Pathology Lab., U.S. Department of Agriculture Beltsville, MD, USA.

ABSTRACT
This study demonstrates that the accumulation of apoplastic phenolics is stimulated in planta in response to bacterial inoculation. Past studies have shown that levels of extracellular phenolics are elicited in plant cell suspensions in response to bacteria, and that tomato plants infected with viroids showed changes in apoplastic phenolics. The method described here monitored changes in apoplastic phenolics in tobacco leaves following bacterial inoculation of the same tissue. Inoculation with a saprophyte, Pseudomonas fluorescens, which does not cause visible symptoms or physical damage, was used to elicit phenolics and examine the effects of variable parameters on phenolic composition. Location of the inoculation on the leaf, position, or developmental age of the leaf on the plant, and inoculum concentration were standardized for further experiments. The patterns of phenolic change in the apoplast were compared for tobacco inoculated with P. syringae pathovars, pv. syringae, which causes a resistant HR reaction within 15 h, and pv. tabaci, which causes a susceptible reaction with delayed visible symptoms. Both pathogens elicited lower increased levels of acetosyringone compared to the saprophyte, P. fluorescens but had greatly increased levels of the chlorogenic acid derivatives. The latter metabolites appear to have come from the intracellular stores, which could indicate a weakening of the apoplast/symplast barrier. This unexpected aspect will require further study of intracellular phenolics.

No MeSH data available.


Related in: MedlinePlus

Effect of segment location within the leaf on production of apoplastic phenolics in response to P. fluorescens. Leaf segments located at the tip, middle, or base of the leaf were infiltrated with 108 CFU ml−1P. fluorescens. After 6 h the segments were analyzed for phenolic content using UPLC/UV/MS. The major phenolics are identified by retention time. See Materials and Methods for further details.
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Figure 1: Effect of segment location within the leaf on production of apoplastic phenolics in response to P. fluorescens. Leaf segments located at the tip, middle, or base of the leaf were infiltrated with 108 CFU ml−1P. fluorescens. After 6 h the segments were analyzed for phenolic content using UPLC/UV/MS. The major phenolics are identified by retention time. See Materials and Methods for further details.

Mentions: The induced apoplastic phenolics from base, center, and tip segments of the same leaf were compared (Figure 1). The same phenolics, were found in all segments with a slight increase in relative concentration from base to tip segments. For further experiments only the two center segments on either side of midrib were used. To avoid possible contamination from one segment to another only one treatment per leaf was used.


The dynamics of apoplast phenolics in tobacco leaves following inoculation with bacteria.

Baker CJ, Mock NM, Smith JM, Aver'yanov AA - Front Plant Sci (2015)

Effect of segment location within the leaf on production of apoplastic phenolics in response to P. fluorescens. Leaf segments located at the tip, middle, or base of the leaf were infiltrated with 108 CFU ml−1P. fluorescens. After 6 h the segments were analyzed for phenolic content using UPLC/UV/MS. The major phenolics are identified by retention time. See Materials and Methods for further details.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4542506&req=5

Figure 1: Effect of segment location within the leaf on production of apoplastic phenolics in response to P. fluorescens. Leaf segments located at the tip, middle, or base of the leaf were infiltrated with 108 CFU ml−1P. fluorescens. After 6 h the segments were analyzed for phenolic content using UPLC/UV/MS. The major phenolics are identified by retention time. See Materials and Methods for further details.
Mentions: The induced apoplastic phenolics from base, center, and tip segments of the same leaf were compared (Figure 1). The same phenolics, were found in all segments with a slight increase in relative concentration from base to tip segments. For further experiments only the two center segments on either side of midrib were used. To avoid possible contamination from one segment to another only one treatment per leaf was used.

Bottom Line: The patterns of phenolic change in the apoplast were compared for tobacco inoculated with P. syringae pathovars, pv. syringae, which causes a resistant HR reaction within 15 h, and pv. tabaci, which causes a susceptible reaction with delayed visible symptoms.Both pathogens elicited lower increased levels of acetosyringone compared to the saprophyte, P. fluorescens but had greatly increased levels of the chlorogenic acid derivatives.This unexpected aspect will require further study of intracellular phenolics.

View Article: PubMed Central - PubMed

Affiliation: Molecular Plant Pathology Lab., U.S. Department of Agriculture Beltsville, MD, USA.

ABSTRACT
This study demonstrates that the accumulation of apoplastic phenolics is stimulated in planta in response to bacterial inoculation. Past studies have shown that levels of extracellular phenolics are elicited in plant cell suspensions in response to bacteria, and that tomato plants infected with viroids showed changes in apoplastic phenolics. The method described here monitored changes in apoplastic phenolics in tobacco leaves following bacterial inoculation of the same tissue. Inoculation with a saprophyte, Pseudomonas fluorescens, which does not cause visible symptoms or physical damage, was used to elicit phenolics and examine the effects of variable parameters on phenolic composition. Location of the inoculation on the leaf, position, or developmental age of the leaf on the plant, and inoculum concentration were standardized for further experiments. The patterns of phenolic change in the apoplast were compared for tobacco inoculated with P. syringae pathovars, pv. syringae, which causes a resistant HR reaction within 15 h, and pv. tabaci, which causes a susceptible reaction with delayed visible symptoms. Both pathogens elicited lower increased levels of acetosyringone compared to the saprophyte, P. fluorescens but had greatly increased levels of the chlorogenic acid derivatives. The latter metabolites appear to have come from the intracellular stores, which could indicate a weakening of the apoplast/symplast barrier. This unexpected aspect will require further study of intracellular phenolics.

No MeSH data available.


Related in: MedlinePlus