The early diagnosis and fast detection of blast fungus, Magnaporthe grisea, in rice plant by using its chitinase as biochemical marker and a rice cDNA encoding mannose-binding lectin as recognition probe.

As one of the most destructive and widespread disease of rice, Magnaporthe grisea (M. grisea) has a significant negative impact on rice production. Therefore, it is significant to develop a method for sensitive and high-throughput detection of M. grisea in order to help farmers to find and control blast in the early stage. We herein first cloned and expressed the M. grisea's chitinases (Mgchi) and a rice cDNA encoding mannose-binding jacalin-related lectin (Osmbl) with Mgchi-related gene. We demonstrated that Mgchi could be used as a biochemical marker for the detection of M. grisea and there was a specific interaction between Osmbl and Mgchi. Using Mgchi as biochemical marker and Osmbl as recognition probe, we developed a visual method for the specific and sensitive detection of M. grisea based on the PdNPs-catalyzed TMB/H(2)O(2) system. The proposed method could be used to detect Mgchi as low as 7.5×10(-9) M by naked eye observation and 2.5×10(-11) M Mgchi by the micro-plate reader. With the help of the method, we had successfully detected M. grisea in the real M. grisea-infected rice plant with recoveries of 88-109% and RSD<7%. The proposed method was sensitive, specific, potentially high-throughput and cost-effective. The success in this study provides a promising substitution for the early diagnosis and fast screening of M. grisea in rice plant.