Wheat leaf rust is one of the world’s most widespread rusts. The progress of the disease
was monitored using two treatments: chitosan nanoparticles and salicylic acid (SA), as well as
three application methods; spraying before or after the inoculation by 24 h, and spraying both
before and after the inoculation by 24 h. Urediniospore germination was significantly different
between the two treatments. Wheat plants tested for latent and incubation periods, pustule size and
receptivity and infection type showed significantly reduced leaf rust when compared to untreated
plants. Puccinia triticina urediniospores showed abnormalities, collapse, lysis, and shrinkage as a
result of chitosan nanoparticles treatment. The enzymes, peroxidase and catalase, were increased in
the activities. In both treatments, superoxide (O2
􀀀) and hydrogen peroxide (H2O2), were apparent as
purple and brown discolorations. Chitosan nanoparticles and SA treatments resulted in much more
discoloration and quantitative measurements than untreated plants. In anatomical examinations,
chitosan nanoparticles enhanced thickness of blade (), thickness of mesophyll tissue, thickness of
the lower and upper epidermis and bundle length and width in the midrib compared to the control.
In the control treatment’s top epidermis, several sori and a large number of urediniospores were
found. Most anatomical characters of flag leaves in control plants were reduced by biotic stress with
P. triticina. Transcription levels of PR1-PR5 and PR10 genes were activated in chitosan nanoparticles
treated plants at 0, 1 and 2 days after inoculation. In light of the data, we suggest that the prospective
use of chitosan nanoparticles might be an eco-friendly strategy to improve growth and control of leaf
rust disease.