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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

Somatic homologous recombination (SHR) in A. thaliana plants with generational exposure to Fe deficiency and grown under Fe deficiency or sufficiency. (A)A. thaliana SHR-trap 1445 c0 plants grown in control, pH 7.7 or pH 8.4 soil. (B) s1 plants (pH 7.7 s1 and pH 8.4 s1) grown in control, pH 7.7 or pH 8.4 soil. (C) s1s2 and s1c2 plants (pH 7.7 s1 pH 7.7 s2, pH 8.4 s1 pH 8.4 s2, pH 7.7 s1 c2, pH 8.4 s1 c2) grown in control soil. For all experiments, plants were grown for 2–3 weeks and rosette leaves were GUS-stained for detection of SHR events, counted as number of independent blue spots/mg fresh weight. Each value represents the mean spots number ± SE in five to twenty leaves. Significant differences (with respect to control c0 value) are indicated with ∗∗(p < 0.01) or ∗(p < 0.05), according to Student’s t-test.
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Figure 2: Somatic homologous recombination (SHR) in A. thaliana plants with generational exposure to Fe deficiency and grown under Fe deficiency or sufficiency. (A)A. thaliana SHR-trap 1445 c0 plants grown in control, pH 7.7 or pH 8.4 soil. (B) s1 plants (pH 7.7 s1 and pH 8.4 s1) grown in control, pH 7.7 or pH 8.4 soil. (C) s1s2 and s1c2 plants (pH 7.7 s1 pH 7.7 s2, pH 8.4 s1 pH 8.4 s2, pH 7.7 s1 c2, pH 8.4 s1 c2) grown in control soil. For all experiments, plants were grown for 2–3 weeks and rosette leaves were GUS-stained for detection of SHR events, counted as number of independent blue spots/mg fresh weight. Each value represents the mean spots number ± SE in five to twenty leaves. Significant differences (with respect to control c0 value) are indicated with ∗∗(p < 0.01) or ∗(p < 0.05), according to Student’s t-test.

Mentions: Frequency of SHR events was then evaluated in the following SHR-trap 1445 generations: c0 (Figure 2A), s1 (Figure 2B), s1s2 and s1c2 (Figure 2C); for that, they were grown in control, pH 7.7 or pH 8.4 soil followed by GUS staining of leaves. SHR frequency in c0 plants grown at either pH 7.7 or pH 8.4 is roughly ten times higher than that observed in c0 plants grown in control soil (Figure 2A). Such higher SHR frequency was maintained, though it did not increase further in plants grown under Fe deficiency and produced from mother plants which were also grown under the same stress, as shown for pH 7.7 s1 grown in pH 7.7 soil and pH 8.4 s1 grown in pH 8.4 soil (Figure 2B). The lack of additive effect suggests a control of SHR frequency, with a plateau effect. Notably, when either pH 7.7 s1 or pH 8.4 s1 are grown in control soil, the SHR frequency was drastically reduced (Figure 2B) but was still higher than control, suggesting occurrence of a faint “stress memory.” Such memory was, however, completely erased when plants were grown for two successive generations in control soil, as was evident in pH 7.7 s1 c2 and pH 8.4 s1 c2 generations grown again in control soil (Figure 2C). It is also interesting to note that growth for two successive generations under Fe deficiency did not reinforce stress memory in offspring unexposed to stress, as observed in pH 7.7 s1 pH 7.7 s2 and pH 8.4 s1 pH 8.4 s2 lines, grown in control soil (Figure 2C).


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)

Somatic homologous recombination (SHR) in A. thaliana plants with generational exposure to Fe deficiency and grown under Fe deficiency or sufficiency. (A)A. thaliana SHR-trap 1445 c0 plants grown in control, pH 7.7 or pH 8.4 soil. (B) s1 plants (pH 7.7 s1 and pH 8.4 s1) grown in control, pH 7.7 or pH 8.4 soil. (C) s1s2 and s1c2 plants (pH 7.7 s1 pH 7.7 s2, pH 8.4 s1 pH 8.4 s2, pH 7.7 s1 c2, pH 8.4 s1 c2) grown in control soil. For all experiments, plants were grown for 2–3 weeks and rosette leaves were GUS-stained for detection of SHR events, counted as number of independent blue spots/mg fresh weight. Each value represents the mean spots number ± SE in five to twenty leaves. Significant differences (with respect to control c0 value) are indicated with ∗∗(p < 0.01) or ∗(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 2: Somatic homologous recombination (SHR) in A. thaliana plants with generational exposure to Fe deficiency and grown under Fe deficiency or sufficiency. (A)A. thaliana SHR-trap 1445 c0 plants grown in control, pH 7.7 or pH 8.4 soil. (B) s1 plants (pH 7.7 s1 and pH 8.4 s1) grown in control, pH 7.7 or pH 8.4 soil. (C) s1s2 and s1c2 plants (pH 7.7 s1 pH 7.7 s2, pH 8.4 s1 pH 8.4 s2, pH 7.7 s1 c2, pH 8.4 s1 c2) grown in control soil. For all experiments, plants were grown for 2–3 weeks and rosette leaves were GUS-stained for detection of SHR events, counted as number of independent blue spots/mg fresh weight. Each value represents the mean spots number ± SE in five to twenty leaves. Significant differences (with respect to control c0 value) are indicated with ∗∗(p < 0.01) or ∗(p < 0.05), according to Student’s t-test.
Mentions: Frequency of SHR events was then evaluated in the following SHR-trap 1445 generations: c0 (Figure 2A), s1 (Figure 2B), s1s2 and s1c2 (Figure 2C); for that, they were grown in control, pH 7.7 or pH 8.4 soil followed by GUS staining of leaves. SHR frequency in c0 plants grown at either pH 7.7 or pH 8.4 is roughly ten times higher than that observed in c0 plants grown in control soil (Figure 2A). Such higher SHR frequency was maintained, though it did not increase further in plants grown under Fe deficiency and produced from mother plants which were also grown under the same stress, as shown for pH 7.7 s1 grown in pH 7.7 soil and pH 8.4 s1 grown in pH 8.4 soil (Figure 2B). The lack of additive effect suggests a control of SHR frequency, with a plateau effect. Notably, when either pH 7.7 s1 or pH 8.4 s1 are grown in control soil, the SHR frequency was drastically reduced (Figure 2B) but was still higher than control, suggesting occurrence of a faint “stress memory.” Such memory was, however, completely erased when plants were grown for two successive generations in control soil, as was evident in pH 7.7 s1 c2 and pH 8.4 s1 c2 generations grown again in control soil (Figure 2C). It is also interesting to note that growth for two successive generations under Fe deficiency did not reinforce stress memory in offspring unexposed to stress, as observed in pH 7.7 s1 pH 7.7 s2 and pH 8.4 s1 pH 8.4 s2 lines, grown in control soil (Figure 2C).

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