Differences in protein expression and ultrastructure between two wheat near-isogenic lines affected by powdery mildew
ABSTRACT Wheat powdery mildew is caused by Blumeria graminis f. sp. tritici (Bgt). Pm21 is an effective broad-spectrum powdery mildew resistance gene, which shows a considerable promise in wheat breeding. We report
here a proteomic approach to investigate the resistance response proteins after fungal infection and emphasize the resistance
changes induced by Pm21. Two wheat (Triticum aestivum L.) near-isogenic lines (NILs), recurrent parent ‘Bainong,’ which is susceptible to powdery mildew, and its near-isogenic
line ‘W2132’ carrying resistance gene Pm21) were used to investigate some changes in their proteomes after being infected. Proteins were extracted from the leaves sampled
in 48 h after inoculation, separated by two-dimensional electrophoresis, and stained with Coomassie brilliant blue. Among
these proteins, a total of 56 spots differentially expressed after Bgt infection were detected. Sixteen proteins, identified
by MALDI-TOF-MS, exhibited more than a 1.5-fold increase upon fungal infection. Unfortunately, three spots were not identified
successfully. The predicted functions of identified proteins were related to energy metabolism and defensive responses; they
were involved in many physiological resistance responses, including enhancing energy metabolism, proteins synthesis and stabilization,
antioxidant reactions, cell-wall reinforcement, and lignification. Interestingly that the expression of two proteins related
to the cell-wall reinforcement was enhanced in the resistant line and one protein related to photosynthesis was lost in a
susceptible line. By transmission electronic microscopy, the corresponding physiological characteristics were also observed.
These results provide us with the information to further reveal the resistance mechanism of Pm21 action and comprehensively investigate the physiological response to powdery mildew at the protein level.
Blumeria graminis f. sp. tritici
–powdery mildew–proteomics–transmission electron microscopy