PMID:26631591 The Y137H mutation of VvCYP51 gene confers the reduced sensitivity to tebuconazole in Villosiclava virens.

[MPiovesana]

Curated by @MPiovesana https://canto.phi-base.org/curs/4ed18899763f7b9f

[MPiovesana]

A mutant allele of the CYP51 gene of Villosiclava virens was identified in a UV-irradiated mutant. The allele carries a point mutation which causes the Y137H amino acid substitution. The UV-irradiated mutant displayed increased resistance to tebuconazole compared to the parental strain (FJ4-1b), and a genetic transformation experiment confirmed the relationship between the mutant allele and chemical resistance.

[MPiovesana]

Uniprot ID: authors used two wild type strains (UV-8a and FJ4-1b) as reference in this study. They sequenced the CYP51 gene of both strains (which were identical), and deposited the sequence in GenBank (KJ004673). This accession number was used to retrieve the Uniprot ID of the protein (X2GGV8).

Strain: strain FJ4-1b was used as a recipient for the genetic transformation experiment.

[MPiovesana]

Genotype creation: as two experiments in this paper describe the generation of similar genotypes (one by UV irradiation and one by genetic transformation), I decided to curate the genetic transformation experiment only. A transformant allele was created to indicate the introduction of the mutant CYP51 allele from mutant UV10th (generated in the study by UV irradiation) into strain FJ4-1b:

CYP51 transformant (UV10th-CYP51(Y137H)) [Not assayed]

The recipient strain was also transformed with the WT CYP51 allele derived from itself (not a complementation control experiment as there is no mention of deleting the endogenous WT gene; the resulting lines from this transformation correspond to overexpression lines of CYP51):

CYP51+ [overexpression]

The presence of the endogenous CYP51 gene (authors do not mention deletion or gene replacement, so it can be assumed that the endogenous copy is still present) was recorded in background.

[MPiovesana]

Genotype annotation: both genotypes display increased resistance to tebuconazole compared to the parental FJ4-1b strain. The CYP51+ overexpression lines also show reduced colony growth rate, while the difference between WT and the CYP51 transformant is not significant (Table 2). The opposite is true when comparing sporulation, with the mutant allele causing a decrease whilst the overexpression of the WT allele does not affect this parameter. Neither allele affects spore germination. The following PHIPO terms were used:

resistance to tebuconazole decreased rate of hyphae formation normal hyphal growth normal number of asexual spores decreased number of asexual spores normal asexual spore germination frequency

[MPiovesana]

Curation completed pending review.

[CuzickA]

Villosiclava virens (anamorph: Ustilaginoidea virens) also see https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1159556

[CuzickA]

I don't think this is correct

There is no comparison with the WT strain here so we can't tell if the overexpression line (white squares) is more or less R to the chemical

Text from results 'To investigate whether overexpression of the VvCYP51 gene was able to confer the reduced sensitivity to tebuconazole, the expression of the gene was determined in 26 pB-Vv51wt transformants and in parental isolate FJ4-1b. Different levels of relative expression ranging from 2.57 to 24.23 were observed (Table 1). EC50 values of the 26 pB-Vv51wt transformants ranged between 0.11 and 0.32 μ g/ml and resistance factors ranged between 2.52 and 7.71 (Table 1). According to linear regression analysis, no correlation was observed between the VvCYP51 expression levels and tebuconazole sensitivity (Fig. 4).'

Text from discussion 'While previous studies associated overexpression of CYP51B with resistance to DMI fungicides, this study showed that a single point mutation rather than overexpression was associated with the reduced sensitivity.'

Text from abstract 'Transformants carrying the mutated gene were more resistant to tebuconazole compared to control transformants lacking the mutation, but the expression of the VvCYP51 gene was not significantly correlated with EC50 values.'

Therefore I am changing the annotation to

[CuzickA]

I have also added in the genotype and annotations for the UV mutant.

And increased RNA level.

[CuzickA]

Also added AE alteration in archetype

[CuzickA]

Approved and closing ticket

[CuzickA]

AE alteration_in _archetype

Y137H; Cyp51 (Cyp51B); SEPTTR

Straight forward to find in Nichola's S file in Table S2, Question about Cyp51/Cyp51B

Questions for Nichola 1) Which cyp51a or cyp51b paralogue, and naming convention, same question as https://github.com/PHI-base/curation/issues/172

AC: Cyp51B is correct

[CuzickA]

AE alteration_in _archetype checked by Nichola. Session now approved.