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Sina and Sinb genes in triticale do not determine grain hardness contrary to their orthologs Pina and Pinb in wheat.

Gasparis S, Orczyk W, Nadolska-Orczyk A - BMC Plant Biol. (2013)

Bottom Line: Silencing of the Sin genes resulted in a substantial decrease of secaloindoline a and secaloindoline b content.We documented that RNAi-based silencing of Sin genes resulted in significant decrease of their transcripts and the level of both secaloindoline proteins, however did not affect grain hardness.The unexpected, functional differences of Sin genes from triticale compared with their orthologs, Pin of wheat, are discussed.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Functional Genetics, Plant Breeding and Acclimatization Institute - National Research Institute, Radzikow, 05-870 Blonie, Poland. a.orczyk@ihar.edu.pl.

ABSTRACT

Background: Secaloindoline a (Sina) and secaloindoline b (Sinb) genes of hexaploid triticale (x Triticosecale Wittmack) are orthologs of puroindoline a (Pina) and puroindoline b (Pinb) in hexaploid wheat (Triticum aestivum L.). It has already been proven that RNA interference (RNAi)-based silencing of Pina and Pinb genes significantly decreased the puroindoline a and puroindoline b proteins in wheat and essentially increased grain hardness (J Exp Bot 62:4025-4036, 2011). The function of Sina and Sinb in triticale was tested by means of RNAi silencing and compared to wheat.

Results: Novel Sina and Sinb alleles in wild-type plants of cv. Wanad were identified and their expression profiles characterized. Alignment with wheat Pina-D1a and Pinb-D1a alleles showed 95% and 93.3% homology with Sina and Sinb coding sequences. Twenty transgenic lines transformed with two hpRNA silencing cassettes directed to silence Sina or Sinb were obtained by the Agrobacterium-mediated method. A significant decrease of expression of both Sin genes in segregating progeny of tested T1 lines was observed independent of the silencing cassette used. The silencing was transmitted to the T4 kernel generation. The relative transcript level was reduced by up to 99% in T3 progeny with the mean for the sublines being around 90%. Silencing of the Sin genes resulted in a substantial decrease of secaloindoline a and secaloindoline b content. The identity of SIN peptides was confirmed by mass spectrometry. The hardness index, measured by the SKCS (Single Kernel Characterization System) method, ranged from 22 to 56 in silent lines and from 37 to 49 in the control, and the mean values were insignificantly lower in the silent ones, proving increased softness. Additionally, the mean total seed protein content of silenced lines was about 6% lower compared with control lines. Correlation coefficients between hardness and transcript level were weakly positive.

Conclusions: We documented that RNAi-based silencing of Sin genes resulted in significant decrease of their transcripts and the level of both secaloindoline proteins, however did not affect grain hardness. The unexpected, functional differences of Sin genes from triticale compared with their orthologs, Pin of wheat, are discussed.

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Profiles of Sina (upper line) and Sinb (lower line) gene expression in developing spikes of the non-transgenic plants of cv. Wanad from 8th to 32nd day after pollination (DAP).
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Figure 1: Profiles of Sina (upper line) and Sinb (lower line) gene expression in developing spikes of the non-transgenic plants of cv. Wanad from 8th to 32nd day after pollination (DAP).

Mentions: Expression profiles of Sin genes in developing spikes from 8 DAP to 32 DAP of wild type plants of cv. Wanad were determined (FigureĀ 1). The relative level of Sina transcript was growing up to 26 DAP and the peak was 54 times higher compared to 8 DAP. The transcript of Sinb started to accumulate from 8 DAP up to 26 DAP, reaching 44 times higher expression compared to 8 DAP. There was a respective decline of profiles of both genes from 26 DAP to 32 DAP. The profiles were parallel to each other, with a 20% to 30% lower transcript level of Sinb compared with Sina.


Sina and Sinb genes in triticale do not determine grain hardness contrary to their orthologs Pina and Pinb in wheat.

Gasparis S, Orczyk W, Nadolska-Orczyk A - BMC Plant Biol. (2013)

Profiles of Sina (upper line) and Sinb (lower line) gene expression in developing spikes of the non-transgenic plants of cv. Wanad from 8th to 32nd day after pollination (DAP).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4222565&req=5

Figure 1: Profiles of Sina (upper line) and Sinb (lower line) gene expression in developing spikes of the non-transgenic plants of cv. Wanad from 8th to 32nd day after pollination (DAP).
Mentions: Expression profiles of Sin genes in developing spikes from 8 DAP to 32 DAP of wild type plants of cv. Wanad were determined (FigureĀ 1). The relative level of Sina transcript was growing up to 26 DAP and the peak was 54 times higher compared to 8 DAP. The transcript of Sinb started to accumulate from 8 DAP up to 26 DAP, reaching 44 times higher expression compared to 8 DAP. There was a respective decline of profiles of both genes from 26 DAP to 32 DAP. The profiles were parallel to each other, with a 20% to 30% lower transcript level of Sinb compared with Sina.

Bottom Line: Silencing of the Sin genes resulted in a substantial decrease of secaloindoline a and secaloindoline b content.We documented that RNAi-based silencing of Sin genes resulted in significant decrease of their transcripts and the level of both secaloindoline proteins, however did not affect grain hardness.The unexpected, functional differences of Sin genes from triticale compared with their orthologs, Pin of wheat, are discussed.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Functional Genetics, Plant Breeding and Acclimatization Institute - National Research Institute, Radzikow, 05-870 Blonie, Poland. a.orczyk@ihar.edu.pl.

ABSTRACT

Background: Secaloindoline a (Sina) and secaloindoline b (Sinb) genes of hexaploid triticale (x Triticosecale Wittmack) are orthologs of puroindoline a (Pina) and puroindoline b (Pinb) in hexaploid wheat (Triticum aestivum L.). It has already been proven that RNA interference (RNAi)-based silencing of Pina and Pinb genes significantly decreased the puroindoline a and puroindoline b proteins in wheat and essentially increased grain hardness (J Exp Bot 62:4025-4036, 2011). The function of Sina and Sinb in triticale was tested by means of RNAi silencing and compared to wheat.

Results: Novel Sina and Sinb alleles in wild-type plants of cv. Wanad were identified and their expression profiles characterized. Alignment with wheat Pina-D1a and Pinb-D1a alleles showed 95% and 93.3% homology with Sina and Sinb coding sequences. Twenty transgenic lines transformed with two hpRNA silencing cassettes directed to silence Sina or Sinb were obtained by the Agrobacterium-mediated method. A significant decrease of expression of both Sin genes in segregating progeny of tested T1 lines was observed independent of the silencing cassette used. The silencing was transmitted to the T4 kernel generation. The relative transcript level was reduced by up to 99% in T3 progeny with the mean for the sublines being around 90%. Silencing of the Sin genes resulted in a substantial decrease of secaloindoline a and secaloindoline b content. The identity of SIN peptides was confirmed by mass spectrometry. The hardness index, measured by the SKCS (Single Kernel Characterization System) method, ranged from 22 to 56 in silent lines and from 37 to 49 in the control, and the mean values were insignificantly lower in the silent ones, proving increased softness. Additionally, the mean total seed protein content of silenced lines was about 6% lower compared with control lines. Correlation coefficients between hardness and transcript level were weakly positive.

Conclusions: We documented that RNAi-based silencing of Sin genes resulted in significant decrease of their transcripts and the level of both secaloindoline proteins, however did not affect grain hardness. The unexpected, functional differences of Sin genes from triticale compared with their orthologs, Pin of wheat, are discussed.

Show MeSH
Related in: MedlinePlus