Studies on the Leaf Blight of Rice Plant III. A Metabolite of the Pathogenic Bacteria

Alteration of content of carbohydrates, nitrogenous and phosphorous compounds in rice plant leaves infected by Xanthomonas oryzae was investigated.1. In the inoculated leaves, contents of reducing and unreducing sugar slightly increased at the early stage of the infection. Moreover crude starch content increased, while total carbohydrate and hemicellulose-carbohydrate content decreased by the infection.2. High accumulation of free ammonia, low contents of water soluble protein and water insoluble protein-nitrogen were characteristic of the inoculated leaves. With the progress of the disease, total nitrogen content decreased gradually. According to the results of molecular weight classification of water soluble protein, the contents of high molecular weight protein, especially “fraction I protein”, decreased and low molecular weight protein increased by the infection.3. At the early stage of the infection, increases of acid soluble phosphorus and inorganic phosphorus contents were observed respectively. During the all experimental periods, there were high contents of total phosphorus and insoluble phosphorus in the inoculated leaves.