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Analysis of the transgenerational iron deficiency stress memory in Arabidopsis thaliana plants.

Murgia I, Giacometti S, Balestrazzi A, Paparella S, Pagliano C, Morandini P - Front Plant Sci (2015)

Bottom Line: However, SHR frequency, DNA strand break events, and TFIIS-like gene expression do not increase further when plants are grown for more than one generation under the same stress, and furthermore, they decrease back to control values within two succeeding generations grown under control conditions, regardless of the Fe deficiency stress history of the mother plants.Lastly, plants grown for multiple generations under Fe deficiency produce seeds with greater longevity: however, this trait is not inherited in offspring generations unexposed to stress.These findings suggest the existence of multiple-step control of mechanisms to prevent a genuine and stable transgenerational transmission of Fe deficiency stress memory, with the tightest control on DNA integrity.

View Article: PubMed Central - PubMed

Affiliation: Department of Biosciences, University of Milano Milano, Italy.

ABSTRACT
We investigated the existence of the transgenerational memory of iron (Fe) deficiency stress, in Arabidopsis thaliana. Plants were grown under Fe deficiency/sufficiency, and so were their offspring. The frequency of somatic homologous recombination (SHR) events, of DNA strand breaks as well as the expression of the transcription elongation factor TFIIS-like gene increase when plants are grown under Fe deficiency. However, SHR frequency, DNA strand break events, and TFIIS-like gene expression do not increase further when plants are grown for more than one generation under the same stress, and furthermore, they decrease back to control values within two succeeding generations grown under control conditions, regardless of the Fe deficiency stress history of the mother plants. Seedlings produced from plants grown under Fe deficiency evolve more oxygen than control seedlings, when grown under Fe sufficiency: however, this trait is not associated with any change in the protein profile of the photosynthetic apparatus and is not transmitted to more than one generation. Lastly, plants grown for multiple generations under Fe deficiency produce seeds with greater longevity: however, this trait is not inherited in offspring generations unexposed to stress. These findings suggest the existence of multiple-step control of mechanisms to prevent a genuine and stable transgenerational transmission of Fe deficiency stress memory, with the tightest control on DNA integrity.

No MeSH data available.


Related in: MedlinePlus

Arabidopsis thaliana seedlings with generational exposure to Fe deficiency and grown under Fe deficiency or sufficiency. (A)A. thaliana SHR-trap 1445 seedlings, from either control generation (c0) or from single (pH 7.7 s1) or multiple generational exposure to Fe deficiency (pH 7.7 s1 pH 7.7 s2) germinated for 11 days in control AIS medium (+Fe), or AIS medium without Fe (-Fe). (B) Chlorophyll content, expressed as mg chlorophyll/g fresh weight of seedlings described in (A). (C) Weight (expressed as mg fresh weight/seedling) of seedlings described in (A). Bars represent mean values ± SE, from at least three biological samples consisting of twenty seedlings each. Significant differences are indicated with letters (p < 0.05), according to Student’s t-test.
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Figure 3: Arabidopsis thaliana seedlings with generational exposure to Fe deficiency and grown under Fe deficiency or sufficiency. (A)A. thaliana SHR-trap 1445 seedlings, from either control generation (c0) or from single (pH 7.7 s1) or multiple generational exposure to Fe deficiency (pH 7.7 s1 pH 7.7 s2) germinated for 11 days in control AIS medium (+Fe), or AIS medium without Fe (-Fe). (B) Chlorophyll content, expressed as mg chlorophyll/g fresh weight of seedlings described in (A). (C) Weight (expressed as mg fresh weight/seedling) of seedlings described in (A). Bars represent mean values ± SE, from at least three biological samples consisting of twenty seedlings each. Significant differences are indicated with letters (p < 0.05), according to Student’s t-test.

Mentions: To reduce any variability of results resulting from stunted growth occurring in alkaline soil, SHR frequency was also measured in c0, pH 7.7 s1 and pH 7.7 s1 pH 7.7 s2 seedlings, when germinated on control AIS medium (+Fe) or in AIS medium without iron supplement (-Fe) (Figure 3A). All tested seedlings growing under Fe deficiency were equally affected, in terms of chlorophyll content (Figure 3B). Both pH 7.7 s1 and pH 7.7 s1 pH 7.7 s2 seedlings, grown in +Fe, showed instead a significantly higher chlorophyll content (but not significantly higher fresh weight), with respect to their control c0 seedlings in the same condition (Figures 3B,C). As already observed for SHR frequency (Figure 2), chlorophyll content and seedlings fresh weight did not further increase upon exposure to Fe deficiency for multiple generations (Figures 3B,C). SHR frequency was measured in seedlings treated as described in Figure 3; results confirm that Fe deficiency strongly enhanced SHR frequency, as observed for SHR-trap seedlings c0, pH 7.7 s1, pH 7.7 s1 pH 7.7 s2 grown under Fe deficiency (Figure 4), thus confirming the observations about plants grown on alkaline soil (Figure 2).


Analysis of the transgenerational iron deficiency stress memory in Arabidopsis thaliana plants.

Murgia I, Giacometti S, Balestrazzi A, Paparella S, Pagliano C, Morandini P - Front Plant Sci (2015)

Arabidopsis thaliana seedlings with generational exposure to Fe deficiency and grown under Fe deficiency or sufficiency. (A)A. thaliana SHR-trap 1445 seedlings, from either control generation (c0) or from single (pH 7.7 s1) or multiple generational exposure to Fe deficiency (pH 7.7 s1 pH 7.7 s2) germinated for 11 days in control AIS medium (+Fe), or AIS medium without Fe (-Fe). (B) Chlorophyll content, expressed as mg chlorophyll/g fresh weight of seedlings described in (A). (C) Weight (expressed as mg fresh weight/seedling) of seedlings described in (A). Bars represent mean values ± SE, from at least three biological samples consisting of twenty seedlings each. Significant differences are indicated with letters (p < 0.05), according to Student’s t-test.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4585125&req=5

Figure 3: Arabidopsis thaliana seedlings with generational exposure to Fe deficiency and grown under Fe deficiency or sufficiency. (A)A. thaliana SHR-trap 1445 seedlings, from either control generation (c0) or from single (pH 7.7 s1) or multiple generational exposure to Fe deficiency (pH 7.7 s1 pH 7.7 s2) germinated for 11 days in control AIS medium (+Fe), or AIS medium without Fe (-Fe). (B) Chlorophyll content, expressed as mg chlorophyll/g fresh weight of seedlings described in (A). (C) Weight (expressed as mg fresh weight/seedling) of seedlings described in (A). Bars represent mean values ± SE, from at least three biological samples consisting of twenty seedlings each. Significant differences are indicated with letters (p < 0.05), according to Student’s t-test.
Mentions: To reduce any variability of results resulting from stunted growth occurring in alkaline soil, SHR frequency was also measured in c0, pH 7.7 s1 and pH 7.7 s1 pH 7.7 s2 seedlings, when germinated on control AIS medium (+Fe) or in AIS medium without iron supplement (-Fe) (Figure 3A). All tested seedlings growing under Fe deficiency were equally affected, in terms of chlorophyll content (Figure 3B). Both pH 7.7 s1 and pH 7.7 s1 pH 7.7 s2 seedlings, grown in +Fe, showed instead a significantly higher chlorophyll content (but not significantly higher fresh weight), with respect to their control c0 seedlings in the same condition (Figures 3B,C). As already observed for SHR frequency (Figure 2), chlorophyll content and seedlings fresh weight did not further increase upon exposure to Fe deficiency for multiple generations (Figures 3B,C). SHR frequency was measured in seedlings treated as described in Figure 3; results confirm that Fe deficiency strongly enhanced SHR frequency, as observed for SHR-trap seedlings c0, pH 7.7 s1, pH 7.7 s1 pH 7.7 s2 grown under Fe deficiency (Figure 4), thus confirming the observations about plants grown on alkaline soil (Figure 2).

Bottom Line: However, SHR frequency, DNA strand break events, and TFIIS-like gene expression do not increase further when plants are grown for more than one generation under the same stress, and furthermore, they decrease back to control values within two succeeding generations grown under control conditions, regardless of the Fe deficiency stress history of the mother plants.Lastly, plants grown for multiple generations under Fe deficiency produce seeds with greater longevity: however, this trait is not inherited in offspring generations unexposed to stress.These findings suggest the existence of multiple-step control of mechanisms to prevent a genuine and stable transgenerational transmission of Fe deficiency stress memory, with the tightest control on DNA integrity.

View Article: PubMed Central - PubMed

Affiliation: Department of Biosciences, University of Milano Milano, Italy.

ABSTRACT
We investigated the existence of the transgenerational memory of iron (Fe) deficiency stress, in Arabidopsis thaliana. Plants were grown under Fe deficiency/sufficiency, and so were their offspring. The frequency of somatic homologous recombination (SHR) events, of DNA strand breaks as well as the expression of the transcription elongation factor TFIIS-like gene increase when plants are grown under Fe deficiency. However, SHR frequency, DNA strand break events, and TFIIS-like gene expression do not increase further when plants are grown for more than one generation under the same stress, and furthermore, they decrease back to control values within two succeeding generations grown under control conditions, regardless of the Fe deficiency stress history of the mother plants. Seedlings produced from plants grown under Fe deficiency evolve more oxygen than control seedlings, when grown under Fe sufficiency: however, this trait is not associated with any change in the protein profile of the photosynthetic apparatus and is not transmitted to more than one generation. Lastly, plants grown for multiple generations under Fe deficiency produce seeds with greater longevity: however, this trait is not inherited in offspring generations unexposed to stress. These findings suggest the existence of multiple-step control of mechanisms to prevent a genuine and stable transgenerational transmission of Fe deficiency stress memory, with the tightest control on DNA integrity.

No MeSH data available.


Related in: MedlinePlus