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Comprehensive analysis of CCCH-type zinc finger family genes facilitates functional gene discovery and reflects recent allopolyploidization event in tetraploid switchgrass.

Yuan S, Xu B, Zhang J, Xie Z, Cheng Q, Yang Z, Cai Q, Huang B - BMC Genomics (2015)

Bottom Line: We also found that eight PvC3Hs in Clade-XIV were orthologous to ABA- or stress- responsive CCCH genes in Arabidopsis and rice with functions annotated.Particularly, eight PvC3Hs in Clade-XIV were found involved in stress responses.This information provides a foundation for functional studies of these genes in the future.

View Article: PubMed Central - PubMed

Affiliation: College of Life Science, Nanjing Agricultural University, Nanjing, 210095, PR China. 234435466@qq.com.

ABSTRACT

Background: In recent years, dozens of Arabidopsis and rice CCCH-type zinc finger genes have been functionally studied, many of which confer important traits, such as abiotic and biotic stress tolerance, delayed leaf senescence and improved plant architecture. Switchgrass (Panicum virgatum) is an important bioenergy crop. Identification of agronomically important genes and/or loci is an important step for switchgrass molecular breeding. Annotating switchgrass CCCH genes using translational genomics methods will help further the goal of understanding switchgrass genetics and creating improved varieties.

Results: Taking advantage of the publicly-available switchgrass genomic and transcriptomic databases, we carried out a comprehensive analysis of switchgrass CCCH genes (PvC3Hs). A total of 103 PvC3Hs were identified and divided into 21 clades according to phylogenetic analysis. Genes in the same clade shared similar gene structure and conserved motifs. Chromosomal location analysis showed that most of the duplicated PvC3H gene pairs are in homeologous chromosomes. Evolution analysis of 19 selected PvC3H pairs showed that 42.1% of them were under diversifying selection. Expression atlas of the 103 PvC3Hs in 21 different organs, tissues and developmental stages revealed genes with higher expression levels in lignified cells, vascular cells, or reproductive tissues/organs, suggesting the potential function of these genes in development. We also found that eight PvC3Hs in Clade-XIV were orthologous to ABA- or stress- responsive CCCH genes in Arabidopsis and rice with functions annotated. Promoter and qRT-PCR analyses of Clade-XIV PvC3Hs showed that these eight genes were all responsive to ABA and various stresses.

Conclusions: Genome-wide analysis of PvC3Hs confirmed the recent allopolyploidization event of tetraploid switchgrass from two closely-related diploid progenitors. The short time window after the polyploidization event allowed the existence of a large number of PvC3H genes with a high positive selection pressure onto them. The homeologous pairs of PvC3Hs may contribute to the heterosis of switchgrass and its wide adaptation in different ecological niches. Phylogenetic and gene expression analyses provide informative clues for discovering PvC3H genes in some functional categories. Particularly, eight PvC3Hs in Clade-XIV were found involved in stress responses. This information provides a foundation for functional studies of these genes in the future.

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qRT-PCR analysis of eight Clade-XIV PvC3Hs and twoPvC3Hs in the other clades. Noting that PvC3H1 and −8 were chosen as controls for these two genes were not in Clade-XIV and their promoter regions had very few stress-responsive cis-elements. * Indicates statistically significant difference (P < 0.05) as compared with the control (0 h).
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Fig8: qRT-PCR analysis of eight Clade-XIV PvC3Hs and twoPvC3Hs in the other clades. Noting that PvC3H1 and −8 were chosen as controls for these two genes were not in Clade-XIV and their promoter regions had very few stress-responsive cis-elements. * Indicates statistically significant difference (P < 0.05) as compared with the control (0 h).

Mentions: To validate this hypothesis, we carried out qRT-PCR with eight PvC3Hs in Clade-XIV to see whether or not these genes were responsive to ABA and various stresses. Meanwhile, another two PvC3Hs (PvC3H1 & -8) with fewer ABREs and DREs in their promoters were picked as controls in the qRT-PCR experiment. Using the cut-off value of 2-fold change, we found that the transcript levels of all eight PvC3Hs in Clade-XIV but not PvC3H1 & -8, were dramatically induced under one or more stress treatments (Figure 8). In particular, the expression levels of PvC3H29 and PvC3H39, orthologs to OsDOS (Figure 3), were drastically induced by cold treatment (27- and 138-fold changes, respectively). PvC3H69 and PvC3H75, orthologs to OsTZF1 (Figure 3), remarkably responded to ABA treatment (108- and 44-fold changes, respectively). The transcript level of PvC3H66 increased to 9-fold after 24 hrs salt treatment and the transcript levels of PvC3H12/62/72 increased to more than 5-fold after one or more of the stress treatments within 48 hrs.Figure 8


Comprehensive analysis of CCCH-type zinc finger family genes facilitates functional gene discovery and reflects recent allopolyploidization event in tetraploid switchgrass.

Yuan S, Xu B, Zhang J, Xie Z, Cheng Q, Yang Z, Cai Q, Huang B - BMC Genomics (2015)

qRT-PCR analysis of eight Clade-XIV PvC3Hs and twoPvC3Hs in the other clades. Noting that PvC3H1 and −8 were chosen as controls for these two genes were not in Clade-XIV and their promoter regions had very few stress-responsive cis-elements. * Indicates statistically significant difference (P < 0.05) as compared with the control (0 h).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4352264&req=5

Fig8: qRT-PCR analysis of eight Clade-XIV PvC3Hs and twoPvC3Hs in the other clades. Noting that PvC3H1 and −8 were chosen as controls for these two genes were not in Clade-XIV and their promoter regions had very few stress-responsive cis-elements. * Indicates statistically significant difference (P < 0.05) as compared with the control (0 h).
Mentions: To validate this hypothesis, we carried out qRT-PCR with eight PvC3Hs in Clade-XIV to see whether or not these genes were responsive to ABA and various stresses. Meanwhile, another two PvC3Hs (PvC3H1 & -8) with fewer ABREs and DREs in their promoters were picked as controls in the qRT-PCR experiment. Using the cut-off value of 2-fold change, we found that the transcript levels of all eight PvC3Hs in Clade-XIV but not PvC3H1 & -8, were dramatically induced under one or more stress treatments (Figure 8). In particular, the expression levels of PvC3H29 and PvC3H39, orthologs to OsDOS (Figure 3), were drastically induced by cold treatment (27- and 138-fold changes, respectively). PvC3H69 and PvC3H75, orthologs to OsTZF1 (Figure 3), remarkably responded to ABA treatment (108- and 44-fold changes, respectively). The transcript level of PvC3H66 increased to 9-fold after 24 hrs salt treatment and the transcript levels of PvC3H12/62/72 increased to more than 5-fold after one or more of the stress treatments within 48 hrs.Figure 8

Bottom Line: We also found that eight PvC3Hs in Clade-XIV were orthologous to ABA- or stress- responsive CCCH genes in Arabidopsis and rice with functions annotated.Particularly, eight PvC3Hs in Clade-XIV were found involved in stress responses.This information provides a foundation for functional studies of these genes in the future.

View Article: PubMed Central - PubMed

Affiliation: College of Life Science, Nanjing Agricultural University, Nanjing, 210095, PR China. 234435466@qq.com.

ABSTRACT

Background: In recent years, dozens of Arabidopsis and rice CCCH-type zinc finger genes have been functionally studied, many of which confer important traits, such as abiotic and biotic stress tolerance, delayed leaf senescence and improved plant architecture. Switchgrass (Panicum virgatum) is an important bioenergy crop. Identification of agronomically important genes and/or loci is an important step for switchgrass molecular breeding. Annotating switchgrass CCCH genes using translational genomics methods will help further the goal of understanding switchgrass genetics and creating improved varieties.

Results: Taking advantage of the publicly-available switchgrass genomic and transcriptomic databases, we carried out a comprehensive analysis of switchgrass CCCH genes (PvC3Hs). A total of 103 PvC3Hs were identified and divided into 21 clades according to phylogenetic analysis. Genes in the same clade shared similar gene structure and conserved motifs. Chromosomal location analysis showed that most of the duplicated PvC3H gene pairs are in homeologous chromosomes. Evolution analysis of 19 selected PvC3H pairs showed that 42.1% of them were under diversifying selection. Expression atlas of the 103 PvC3Hs in 21 different organs, tissues and developmental stages revealed genes with higher expression levels in lignified cells, vascular cells, or reproductive tissues/organs, suggesting the potential function of these genes in development. We also found that eight PvC3Hs in Clade-XIV were orthologous to ABA- or stress- responsive CCCH genes in Arabidopsis and rice with functions annotated. Promoter and qRT-PCR analyses of Clade-XIV PvC3Hs showed that these eight genes were all responsive to ABA and various stresses.

Conclusions: Genome-wide analysis of PvC3Hs confirmed the recent allopolyploidization event of tetraploid switchgrass from two closely-related diploid progenitors. The short time window after the polyploidization event allowed the existence of a large number of PvC3H genes with a high positive selection pressure onto them. The homeologous pairs of PvC3Hs may contribute to the heterosis of switchgrass and its wide adaptation in different ecological niches. Phylogenetic and gene expression analyses provide informative clues for discovering PvC3H genes in some functional categories. Particularly, eight PvC3Hs in Clade-XIV were found involved in stress responses. This information provides a foundation for functional studies of these genes in the future.

Show MeSH