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The novel and taxonomically restricted Ah24 gene from grain amaranth (Amaranthus hypochondriacus) has a dual role in development and defense.

Massange-Sanchez JA, Palmeros-Suarez PA, Martinez-Gallardo NA, Castrillon-Arbelaez PA, Avilés-Arnaut H, Alatorre-Cobos F, Tiessen A, Délano-Frier JP - Front Plant Sci (2015)

Bottom Line: Transgenic tobacco plants, which grew and reproduced normally, had increased insect herbivory resistance.Modified vegetative growth in transgenic Arabidopsis coincided with significant changes in the expression of genes controlling phytohormone synthesis or signaling, whereas increased resistance to insect herbivory in transgenic tobacco coincided with higher jasmonic acid and proteinase inhibitor activity levels, plus the accumulation of nicotine and several other putative defense-related metabolites.It is proposed that the primary role of the Ah24 gene in A. hypochondriacus is to contribute to a rapid recovery post-wounding or defoliation, although its participation in defense against insect herbivory is also plausible.

View Article: PubMed Central - PubMed

Affiliation: Biotechnology and Biochemistry Department, Centro de Investigación y de Estudios Avanzados del I. P. N., Unidad Irapuato Irapuato, México.

ABSTRACT
Grain amaranths tolerate stress and produce highly nutritious seeds. We have identified several (a)biotic stress-responsive genes of unknown function in Amaranthus hypochondriacus, including the so-called Ah24 gene. Ah24 was expressed in young or developing tissues; it was also strongly induced by mechanical damage, insect herbivory and methyl jasmonate and in meristems and newly emerging leaves of severely defoliated plants. Interestingly, an in silico analysis of its 1304 bp promoter region showed a predominance of regulatory boxes involved in development, but not in defense. The Ah24 cDNA encodes a predicted cytosolic protein of 164 amino acids, the localization of which was confirmed by confocal microscopy. Additional in silico analysis identified several other Ah24 homologs, present almost exclusively in plants belonging to the Caryophyllales. The possible function of this gene in planta was examined in transgenic Ah24 overexpressing Arabidopsis thaliana and Nicotiana tabacum plants. Transformed Arabidopsis showed enhanced vegetative growth and increased leaf number with no penalty in one fitness component, such as seed yield, in experimental conditions. Transgenic tobacco plants, which grew and reproduced normally, had increased insect herbivory resistance. Modified vegetative growth in transgenic Arabidopsis coincided with significant changes in the expression of genes controlling phytohormone synthesis or signaling, whereas increased resistance to insect herbivory in transgenic tobacco coincided with higher jasmonic acid and proteinase inhibitor activity levels, plus the accumulation of nicotine and several other putative defense-related metabolites. It is proposed that the primary role of the Ah24 gene in A. hypochondriacus is to contribute to a rapid recovery post-wounding or defoliation, although its participation in defense against insect herbivory is also plausible.

No MeSH data available.


Related in: MedlinePlus

Complete 847 bp cDNA sequence of the Ah24 gene and the predicted 164 amino acid protein coded by its open reading frame. Shown in blue and green are sequence regions selected to design the primers used to isolate its genomic sequence by a gene walking strategy and to quantify the Ah24 expression levels by RT-qPCR, respectively.
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Figure 1: Complete 847 bp cDNA sequence of the Ah24 gene and the predicted 164 amino acid protein coded by its open reading frame. Shown in blue and green are sequence regions selected to design the primers used to isolate its genomic sequence by a gene walking strategy and to quantify the Ah24 expression levels by RT-qPCR, respectively.

Mentions: Employing PCR-based cDNA subtraction, a partial Ah24 cDNA clone of 858 bp, containing part of the 5′ UTR region, was obtained from combined cDNA libraries of grain amaranth plants subjected to water- and salt-stress, insect herbivory, and mechanical damage (Fomsgaard et al., 2010). Using 5′ RACE PCR, a full-length 844 bp Ah24 cDNA clone was obtained, including a 65 bp 5′UTR, 492 bp open reading frame (ORF), and 287 bp 3′UTR (GenBank accession number JN384107; Figure 1). The ORF encodes a polypeptide of 164 amino acid residues with a predicted molecular mass of 17.6 kDa and pI of 5.71 (Figure 1). The prediction was corroborated by an 82% identity with fingerprint peptides derived from a proteomic analysis of an A. hypochondriacus protein induced by exogenous MeJA (Navarro-Meléndez, 2009; Figure S1 in Supplementary Materials). Bioinformatic analyses further indicated that the secondary structure of the Ah24 protein includes 6 α helices and 3 β-sheets (Figure S2A in Supplementary Materials). Also predicted were one possible N glycosylation site (N41L42) and four putative protein kinase C tyrosine phosphorylation sites, at positions Y43, Y74, Y98, and Y162 (Figure S2B in Supplementary Materials).


The novel and taxonomically restricted Ah24 gene from grain amaranth (Amaranthus hypochondriacus) has a dual role in development and defense.

Massange-Sanchez JA, Palmeros-Suarez PA, Martinez-Gallardo NA, Castrillon-Arbelaez PA, Avilés-Arnaut H, Alatorre-Cobos F, Tiessen A, Délano-Frier JP - Front Plant Sci (2015)

Complete 847 bp cDNA sequence of the Ah24 gene and the predicted 164 amino acid protein coded by its open reading frame. Shown in blue and green are sequence regions selected to design the primers used to isolate its genomic sequence by a gene walking strategy and to quantify the Ah24 expression levels by RT-qPCR, respectively.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4524895&req=5

Figure 1: Complete 847 bp cDNA sequence of the Ah24 gene and the predicted 164 amino acid protein coded by its open reading frame. Shown in blue and green are sequence regions selected to design the primers used to isolate its genomic sequence by a gene walking strategy and to quantify the Ah24 expression levels by RT-qPCR, respectively.
Mentions: Employing PCR-based cDNA subtraction, a partial Ah24 cDNA clone of 858 bp, containing part of the 5′ UTR region, was obtained from combined cDNA libraries of grain amaranth plants subjected to water- and salt-stress, insect herbivory, and mechanical damage (Fomsgaard et al., 2010). Using 5′ RACE PCR, a full-length 844 bp Ah24 cDNA clone was obtained, including a 65 bp 5′UTR, 492 bp open reading frame (ORF), and 287 bp 3′UTR (GenBank accession number JN384107; Figure 1). The ORF encodes a polypeptide of 164 amino acid residues with a predicted molecular mass of 17.6 kDa and pI of 5.71 (Figure 1). The prediction was corroborated by an 82% identity with fingerprint peptides derived from a proteomic analysis of an A. hypochondriacus protein induced by exogenous MeJA (Navarro-Meléndez, 2009; Figure S1 in Supplementary Materials). Bioinformatic analyses further indicated that the secondary structure of the Ah24 protein includes 6 α helices and 3 β-sheets (Figure S2A in Supplementary Materials). Also predicted were one possible N glycosylation site (N41L42) and four putative protein kinase C tyrosine phosphorylation sites, at positions Y43, Y74, Y98, and Y162 (Figure S2B in Supplementary Materials).

Bottom Line: Transgenic tobacco plants, which grew and reproduced normally, had increased insect herbivory resistance.Modified vegetative growth in transgenic Arabidopsis coincided with significant changes in the expression of genes controlling phytohormone synthesis or signaling, whereas increased resistance to insect herbivory in transgenic tobacco coincided with higher jasmonic acid and proteinase inhibitor activity levels, plus the accumulation of nicotine and several other putative defense-related metabolites.It is proposed that the primary role of the Ah24 gene in A. hypochondriacus is to contribute to a rapid recovery post-wounding or defoliation, although its participation in defense against insect herbivory is also plausible.

View Article: PubMed Central - PubMed

Affiliation: Biotechnology and Biochemistry Department, Centro de Investigación y de Estudios Avanzados del I. P. N., Unidad Irapuato Irapuato, México.

ABSTRACT
Grain amaranths tolerate stress and produce highly nutritious seeds. We have identified several (a)biotic stress-responsive genes of unknown function in Amaranthus hypochondriacus, including the so-called Ah24 gene. Ah24 was expressed in young or developing tissues; it was also strongly induced by mechanical damage, insect herbivory and methyl jasmonate and in meristems and newly emerging leaves of severely defoliated plants. Interestingly, an in silico analysis of its 1304 bp promoter region showed a predominance of regulatory boxes involved in development, but not in defense. The Ah24 cDNA encodes a predicted cytosolic protein of 164 amino acids, the localization of which was confirmed by confocal microscopy. Additional in silico analysis identified several other Ah24 homologs, present almost exclusively in plants belonging to the Caryophyllales. The possible function of this gene in planta was examined in transgenic Ah24 overexpressing Arabidopsis thaliana and Nicotiana tabacum plants. Transformed Arabidopsis showed enhanced vegetative growth and increased leaf number with no penalty in one fitness component, such as seed yield, in experimental conditions. Transgenic tobacco plants, which grew and reproduced normally, had increased insect herbivory resistance. Modified vegetative growth in transgenic Arabidopsis coincided with significant changes in the expression of genes controlling phytohormone synthesis or signaling, whereas increased resistance to insect herbivory in transgenic tobacco coincided with higher jasmonic acid and proteinase inhibitor activity levels, plus the accumulation of nicotine and several other putative defense-related metabolites. It is proposed that the primary role of the Ah24 gene in A. hypochondriacus is to contribute to a rapid recovery post-wounding or defoliation, although its participation in defense against insect herbivory is also plausible.

No MeSH data available.


Related in: MedlinePlus