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Overexpression of a truncated CTF7 construct leads to pleiotropic defects in reproduction and vegetative growth in Arabidopsis.

Liu D, Makaroff CA - BMC Plant Biol. (2015)

Bottom Line: Inactivation of Arabidopsis CTF7 (AtCTF7) results in severe defects in reproduction and vegetative growth.Transgenic plants expressing 35S:AtCTF7∆B displayed similar vegetative defects, suggesting the defects in 35S:NTAP:AtCTF7∆B plants are caused by high-level expression of AtCTF7∆B.High level expression of AtCTF7∆B disrupts megasporogenesis, megagametogenesis and male meiosis, as well as causing a broad range of vegetative defects, including dwarfism that are inherited in a non-Mendelian fashion.

View Article: PubMed Central - PubMed

ABSTRACT

Background: Eco1/Ctf7 is essential for the establishment of sister chromatid cohesion during S phase of the cell cycle. Inactivation of Ctf7/Eco1 leads to a lethal phenotype in most organisms. Altering Eco1/Ctf7 levels or point mutations in the gene can lead to alterations in nuclear division as well as a wide range of developmental defects. Inactivation of Arabidopsis CTF7 (AtCTF7) results in severe defects in reproduction and vegetative growth.

Results: To further investigate the function(s) of AtCTF7, a tagged version of AtCTF7 and several AtCTF7 deletion constructs were created and transformed into wild type or ctf7 +/- plants. Transgenic plants expressing 35S:NTAP:AtCTF7∆299-345 (AtCTF7∆B) displayed a wide range of phenotypic alterations in reproduction and vegetative growth. Male meiocytes exhibited chromosome fragmentation and uneven chromosome segregation. Mutant ovules contained abnormal megasporocyte-like cells during pre-meiosis, megaspores experienced elongated meiosis and megagametogenesis, and defective megaspores/embryo sacs were produced at various stages. The transgenic plants also exhibited a broad range of vegetative defects, including meristem disruption and dwarfism that were inherited in a non-Mendelian fashion. Transcripts for epigenetically regulated transposable elements (TEs) were elevated in transgenic plants. Transgenic plants expressing 35S:AtCTF7∆B displayed similar vegetative defects, suggesting the defects in 35S:NTAP:AtCTF7∆B plants are caused by high-level expression of AtCTF7∆B.

Conclusions: High level expression of AtCTF7∆B disrupts megasporogenesis, megagametogenesis and male meiosis, as well as causing a broad range of vegetative defects, including dwarfism that are inherited in a non-Mendelian fashion.

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35S:NTAP:AtCTF7∆B plant morphology changes in later generations. (A) Wild type Columbia plant. (B-E) Morphological alterations get progressively worse in 35S:NTAP:AtCTF7∆B plants through self-pollination. (B) Second generation plants are normal, but reduced fertile. (C) Both dwarf and non-dwarf, reduced fertile plants are observed in third generation plants. (D) Fourth generation plants. (E) Sixth generation plants, showing a higher frequency of dwarf plants. Defects such as reduced apical dominance (arrow) and phyllotaxis disturbances (asterisks) are observed. (F-I) Representative 35S:NTAP:AtCTF7∆B dwarf plants. Inflorescence defects include acaulescent (G), multiple inflorescence branches at the first node (H) and no inflorescence (I). Leave defects include aberrant rosette size and shape (F, H and I). (J)atctf7-1 plant showing an early senescence phenotype (arrow). Plants B to I are from Line 11. All plants are grown under the same conditions. Plants in A-H and J are approximately 30 days old; plant in I is 40 days old. Scale bar = 5 cm in A-E and 2 cm in F-J.
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Fig6: 35S:NTAP:AtCTF7∆B plant morphology changes in later generations. (A) Wild type Columbia plant. (B-E) Morphological alterations get progressively worse in 35S:NTAP:AtCTF7∆B plants through self-pollination. (B) Second generation plants are normal, but reduced fertile. (C) Both dwarf and non-dwarf, reduced fertile plants are observed in third generation plants. (D) Fourth generation plants. (E) Sixth generation plants, showing a higher frequency of dwarf plants. Defects such as reduced apical dominance (arrow) and phyllotaxis disturbances (asterisks) are observed. (F-I) Representative 35S:NTAP:AtCTF7∆B dwarf plants. Inflorescence defects include acaulescent (G), multiple inflorescence branches at the first node (H) and no inflorescence (I). Leave defects include aberrant rosette size and shape (F, H and I). (J)atctf7-1 plant showing an early senescence phenotype (arrow). Plants B to I are from Line 11. All plants are grown under the same conditions. Plants in A-H and J are approximately 30 days old; plant in I is 40 days old. Scale bar = 5 cm in A-E and 2 cm in F-J.

Mentions: During the analysis of 35S:NTAP:AtCTF7∆B reduced fertility lines, plants displaying vegetative defects began to appear in the T2 or T3 generations. Specifically, later generations grew progressively worse in 12 of the 18 independent severely reduced fertility lines examined. The remaining six lines continued to display reduced fertility, but did not exhibit vegetative defects through the seventh generation. A wide range of morphological defects was observed in the 12 lines (Figure 6). The defects varied between lines and between progeny of the same line. The observed vegetative abnormalities included dwarf plants, fused stems and disruption of phyllotaxis (Figures 6C-E).Figure 6


Overexpression of a truncated CTF7 construct leads to pleiotropic defects in reproduction and vegetative growth in Arabidopsis.

Liu D, Makaroff CA - BMC Plant Biol. (2015)

35S:NTAP:AtCTF7∆B plant morphology changes in later generations. (A) Wild type Columbia plant. (B-E) Morphological alterations get progressively worse in 35S:NTAP:AtCTF7∆B plants through self-pollination. (B) Second generation plants are normal, but reduced fertile. (C) Both dwarf and non-dwarf, reduced fertile plants are observed in third generation plants. (D) Fourth generation plants. (E) Sixth generation plants, showing a higher frequency of dwarf plants. Defects such as reduced apical dominance (arrow) and phyllotaxis disturbances (asterisks) are observed. (F-I) Representative 35S:NTAP:AtCTF7∆B dwarf plants. Inflorescence defects include acaulescent (G), multiple inflorescence branches at the first node (H) and no inflorescence (I). Leave defects include aberrant rosette size and shape (F, H and I). (J)atctf7-1 plant showing an early senescence phenotype (arrow). Plants B to I are from Line 11. All plants are grown under the same conditions. Plants in A-H and J are approximately 30 days old; plant in I is 40 days old. Scale bar = 5 cm in A-E and 2 cm in F-J.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4359560&req=5

Fig6: 35S:NTAP:AtCTF7∆B plant morphology changes in later generations. (A) Wild type Columbia plant. (B-E) Morphological alterations get progressively worse in 35S:NTAP:AtCTF7∆B plants through self-pollination. (B) Second generation plants are normal, but reduced fertile. (C) Both dwarf and non-dwarf, reduced fertile plants are observed in third generation plants. (D) Fourth generation plants. (E) Sixth generation plants, showing a higher frequency of dwarf plants. Defects such as reduced apical dominance (arrow) and phyllotaxis disturbances (asterisks) are observed. (F-I) Representative 35S:NTAP:AtCTF7∆B dwarf plants. Inflorescence defects include acaulescent (G), multiple inflorescence branches at the first node (H) and no inflorescence (I). Leave defects include aberrant rosette size and shape (F, H and I). (J)atctf7-1 plant showing an early senescence phenotype (arrow). Plants B to I are from Line 11. All plants are grown under the same conditions. Plants in A-H and J are approximately 30 days old; plant in I is 40 days old. Scale bar = 5 cm in A-E and 2 cm in F-J.
Mentions: During the analysis of 35S:NTAP:AtCTF7∆B reduced fertility lines, plants displaying vegetative defects began to appear in the T2 or T3 generations. Specifically, later generations grew progressively worse in 12 of the 18 independent severely reduced fertility lines examined. The remaining six lines continued to display reduced fertility, but did not exhibit vegetative defects through the seventh generation. A wide range of morphological defects was observed in the 12 lines (Figure 6). The defects varied between lines and between progeny of the same line. The observed vegetative abnormalities included dwarf plants, fused stems and disruption of phyllotaxis (Figures 6C-E).Figure 6

Bottom Line: Inactivation of Arabidopsis CTF7 (AtCTF7) results in severe defects in reproduction and vegetative growth.Transgenic plants expressing 35S:AtCTF7∆B displayed similar vegetative defects, suggesting the defects in 35S:NTAP:AtCTF7∆B plants are caused by high-level expression of AtCTF7∆B.High level expression of AtCTF7∆B disrupts megasporogenesis, megagametogenesis and male meiosis, as well as causing a broad range of vegetative defects, including dwarfism that are inherited in a non-Mendelian fashion.

View Article: PubMed Central - PubMed

ABSTRACT

Background: Eco1/Ctf7 is essential for the establishment of sister chromatid cohesion during S phase of the cell cycle. Inactivation of Ctf7/Eco1 leads to a lethal phenotype in most organisms. Altering Eco1/Ctf7 levels or point mutations in the gene can lead to alterations in nuclear division as well as a wide range of developmental defects. Inactivation of Arabidopsis CTF7 (AtCTF7) results in severe defects in reproduction and vegetative growth.

Results: To further investigate the function(s) of AtCTF7, a tagged version of AtCTF7 and several AtCTF7 deletion constructs were created and transformed into wild type or ctf7 +/- plants. Transgenic plants expressing 35S:NTAP:AtCTF7∆299-345 (AtCTF7∆B) displayed a wide range of phenotypic alterations in reproduction and vegetative growth. Male meiocytes exhibited chromosome fragmentation and uneven chromosome segregation. Mutant ovules contained abnormal megasporocyte-like cells during pre-meiosis, megaspores experienced elongated meiosis and megagametogenesis, and defective megaspores/embryo sacs were produced at various stages. The transgenic plants also exhibited a broad range of vegetative defects, including meristem disruption and dwarfism that were inherited in a non-Mendelian fashion. Transcripts for epigenetically regulated transposable elements (TEs) were elevated in transgenic plants. Transgenic plants expressing 35S:AtCTF7∆B displayed similar vegetative defects, suggesting the defects in 35S:NTAP:AtCTF7∆B plants are caused by high-level expression of AtCTF7∆B.

Conclusions: High level expression of AtCTF7∆B disrupts megasporogenesis, megagametogenesis and male meiosis, as well as causing a broad range of vegetative defects, including dwarfism that are inherited in a non-Mendelian fashion.

Show MeSH
Related in: MedlinePlus