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Intra and Inter-Spore Variability in Rhizophagus irregularis AOX Gene.

Campos C, Cardoso H, Nogales A, Svensson J, Lopez-Ráez JA, Pozo MJ, Nobre T, Schneider C, Arnholdt-Schmitt B - PLoS ONE (2015)

Bottom Line: Nevertheless, virtually nothing is known on the involvement of AMF AOX on symbiosis establishment, as well on the existence of AOX variability that could affect AMF effectiveness and consequently plant performance.The analysis of RiAOX polymorphisms in single spores of three different isolates showed a reduced variability in one spore relatively to a group of spores.A high number of polymorphisms occurred in introns; nevertheless, some putative amino acid changes resulting from non-synonymous variants were found, offering a basis for selective pressure to occur within the populations.

View Article: PubMed Central - PubMed

Affiliation: EU Marie Curie Chair, ICAAM-Instituto de Ciências Agrárias e Ambientais Mediterrânicas, IIFA-Instituto de Formação e Investigação Avançada, Universidade de Évora, Núcleo da Mitra, Évora, Portugal.

ABSTRACT
Arbuscular mycorrhizal fungi (AMF) are root-inhabiting fungi that form mutualistic symbioses with their host plants. AMF symbiosis improves nutrient uptake and buffers the plant against a diversity of stresses. Rhizophagus irregularis is one of the most widespread AMF species in the world, and its application in agricultural systems for yield improvement has increased over the last years. Still, from the inoculum production perspective, a lack of consistency of inoculum quality is referred to, which partially may be due to a high genetic variability of the fungus. The alternative oxidase (AOX) is an enzyme of the alternative respiratory chain already described in different taxa, including various fungi, which decreases the damage caused by oxidative stress. Nevertheless, virtually nothing is known on the involvement of AMF AOX on symbiosis establishment, as well on the existence of AOX variability that could affect AMF effectiveness and consequently plant performance. Here, we report the isolation and characterisation of the AOX gene of R. irregularis (RiAOX), and show that it is highly expressed during early phases of the symbiosis with plant roots. Phylogenetic analysis clustered RiAOX sequence with ancient fungi, and multiple sequence alignment revealed the lack of several regulatory motifs which are present in plant AOX. The analysis of RiAOX polymorphisms in single spores of three different isolates showed a reduced variability in one spore relatively to a group of spores. A high number of polymorphisms occurred in introns; nevertheless, some putative amino acid changes resulting from non-synonymous variants were found, offering a basis for selective pressure to occur within the populations. Given the AOX relatedness with stress responses, differences in gene variants amongst R. irregularis isolates are likely to be related with its origin and environmental constraints and might have a potential impact on inoculum production.

No MeSH data available.


Related in: MedlinePlus

Distribution of variants along the 1209 bp AOX sequence of R. irregularis.All the 288 variants (SNVs, MNVs, deletions, insertions and replacements) and only the SNVs present in the 9 spores are shown in A). The variants present in INOQ, BEG144 and BEG72 isolates plus the variants unique to each isolate are presented in B), C) and D), respectively.
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pone.0142339.g005: Distribution of variants along the 1209 bp AOX sequence of R. irregularis.All the 288 variants (SNVs, MNVs, deletions, insertions and replacements) and only the SNVs present in the 9 spores are shown in A). The variants present in INOQ, BEG144 and BEG72 isolates plus the variants unique to each isolate are presented in B), C) and D), respectively.

Mentions: When considering all 9 spores, a total of 288 nucleotide variants (including SNVs, MNVs, insertions, deletions and replacements) were found within the 1209 bp sequence length (Fig 5A). Of these 288 variants, 93 corresponded to SNVs (Fig 5A). Many polymorphisms accumulated in the region corresponding to intron 2: 92 of which 38 were SNVs; however, a large number were also found dispersed throughout the sequence, including all exons (Fig 5A, S5 Fig). Only 13 polymorphisms, consisting mostly of insertions or deletions of 1 bp and one SNV were identical between spores.


Intra and Inter-Spore Variability in Rhizophagus irregularis AOX Gene.

Campos C, Cardoso H, Nogales A, Svensson J, Lopez-Ráez JA, Pozo MJ, Nobre T, Schneider C, Arnholdt-Schmitt B - PLoS ONE (2015)

Distribution of variants along the 1209 bp AOX sequence of R. irregularis.All the 288 variants (SNVs, MNVs, deletions, insertions and replacements) and only the SNVs present in the 9 spores are shown in A). The variants present in INOQ, BEG144 and BEG72 isolates plus the variants unique to each isolate are presented in B), C) and D), respectively.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4634980&req=5

pone.0142339.g005: Distribution of variants along the 1209 bp AOX sequence of R. irregularis.All the 288 variants (SNVs, MNVs, deletions, insertions and replacements) and only the SNVs present in the 9 spores are shown in A). The variants present in INOQ, BEG144 and BEG72 isolates plus the variants unique to each isolate are presented in B), C) and D), respectively.
Mentions: When considering all 9 spores, a total of 288 nucleotide variants (including SNVs, MNVs, insertions, deletions and replacements) were found within the 1209 bp sequence length (Fig 5A). Of these 288 variants, 93 corresponded to SNVs (Fig 5A). Many polymorphisms accumulated in the region corresponding to intron 2: 92 of which 38 were SNVs; however, a large number were also found dispersed throughout the sequence, including all exons (Fig 5A, S5 Fig). Only 13 polymorphisms, consisting mostly of insertions or deletions of 1 bp and one SNV were identical between spores.

Bottom Line: Nevertheless, virtually nothing is known on the involvement of AMF AOX on symbiosis establishment, as well on the existence of AOX variability that could affect AMF effectiveness and consequently plant performance.The analysis of RiAOX polymorphisms in single spores of three different isolates showed a reduced variability in one spore relatively to a group of spores.A high number of polymorphisms occurred in introns; nevertheless, some putative amino acid changes resulting from non-synonymous variants were found, offering a basis for selective pressure to occur within the populations.

View Article: PubMed Central - PubMed

Affiliation: EU Marie Curie Chair, ICAAM-Instituto de Ciências Agrárias e Ambientais Mediterrânicas, IIFA-Instituto de Formação e Investigação Avançada, Universidade de Évora, Núcleo da Mitra, Évora, Portugal.

ABSTRACT
Arbuscular mycorrhizal fungi (AMF) are root-inhabiting fungi that form mutualistic symbioses with their host plants. AMF symbiosis improves nutrient uptake and buffers the plant against a diversity of stresses. Rhizophagus irregularis is one of the most widespread AMF species in the world, and its application in agricultural systems for yield improvement has increased over the last years. Still, from the inoculum production perspective, a lack of consistency of inoculum quality is referred to, which partially may be due to a high genetic variability of the fungus. The alternative oxidase (AOX) is an enzyme of the alternative respiratory chain already described in different taxa, including various fungi, which decreases the damage caused by oxidative stress. Nevertheless, virtually nothing is known on the involvement of AMF AOX on symbiosis establishment, as well on the existence of AOX variability that could affect AMF effectiveness and consequently plant performance. Here, we report the isolation and characterisation of the AOX gene of R. irregularis (RiAOX), and show that it is highly expressed during early phases of the symbiosis with plant roots. Phylogenetic analysis clustered RiAOX sequence with ancient fungi, and multiple sequence alignment revealed the lack of several regulatory motifs which are present in plant AOX. The analysis of RiAOX polymorphisms in single spores of three different isolates showed a reduced variability in one spore relatively to a group of spores. A high number of polymorphisms occurred in introns; nevertheless, some putative amino acid changes resulting from non-synonymous variants were found, offering a basis for selective pressure to occur within the populations. Given the AOX relatedness with stress responses, differences in gene variants amongst R. irregularis isolates are likely to be related with its origin and environmental constraints and might have a potential impact on inoculum production.

No MeSH data available.


Related in: MedlinePlus