Quantitative Analysis of Target Peptides Related to Resistance Against Ascochyta Blight (Peyronellaea pinodes) in Pea

Peyronellaea pinodes causes Ascochyta blight, one of the major diseases in pea
worldwide. Cultivated pea plants have a low resistance to this disease.
Although quantitative trait loci (QTLs) involved in the resistance
to Ascochyta blight have been identified,
the specific
genes associated with these QTLs remain unknown, which makes marker-assisted
selection difficult. Complex traits alter proteins and their abundance.
Quantitative estimation of proteins in pea might therefore be useful
in selecting potential markers for breeding. In this work, we developed
a strategy using a combination of shotgun proteomics (viz., high performance
liquid chromatography–mass spectrometry data-dependent acquisition)
and data-independent acquisition (DIA) analysis, to identify putative
protein markers associated with resistance to Ascochyta blight and explored its use for breeding selection. For this purpose,
an initial list of target peptides based on proteins closely related
to resistance to P. pinodes was compiled
by using two genotypes with contrasting responses to the disease.
Then, targeted data analysis (viz., shotgun proteomics-DIA) was used
for constitutive quantification of the target peptides in a representative
number of the recombinant inbred line population segregated for resistance
as derived from a cross between the two genotypes. Finally, a peptide
panel of potential markers for resistance to P. pinodes was built. The results thus obtained are discussed and compared
with those of previous gene expression studies using the same parental
pea genotypes responding to the pathogen. Also, a molecular defense
mechanism against Ascochyta blight
in pea is proposed. To the authors’ knowledge, this is the
first time a targeted proteomics approach based on data analysis has
been used to identify peptides associated with resistance to this
disease.