The defense response in seedling roots of two wheat cultivars with contrasting resistance to Fusarium crown and root rot disease

Fusarium culmorum (Fc) is a hemibiotrophic plant fungal pathogen that causes crown and root rot disease in wheat. In this study, for the first time, a comparative proteomic analysis was made in seedling roots of two wheat cultivars Falat (susceptible) and Sumai3 (resistant) to understand defense responses induced during the early stage of Fc-infection. The patterns of differentially expressed protein spots (DEPs) were located on two-dimensional gel electrophoresis 48 h after F. culmorum inoculation and a total of 30 major protein spots were successfully identified by mass spectrometry. These proteins were grouped into diverse functional categories which were involved in cellular metabolism (70%), defense (10%), energy (10%) and cell structure (3%), while only two proteins were unknown (7%). Seven DEPs were equally up-regulated with significant expression changes in both cultivars, while seventeen DEPs such as isocitrate dehydrogenase, malate dehydrogenase, enolase which are related to cellular respiration besides lipoxygenase that is vital enzyme in jasmonate biosynthesis were up-regulated only in Sumai3. Likewise, RuBisCO, as a photosynthesis responsive DEPs, showed significantly higher abundance only in Falat. These results showed that the resistant cultivar provides required energy for combating pathogen by reducing photosynthesis and increasing cellular respiration during early stage of Fc-infection. Moreover, lipoxygenase as main marker of octadecanoid pathways solitary increased in resistant cv. Sumai3 and there is a direct correlation between expressed proteins and level of defense responses to crown and root rot disease in wheat.