Meloidogyne infections in susceptible hosts - A metabolic quantitation Kannan S., Chandraguru T. Dept. of Zoology, Thiagarajar College, Madurai - 625 009. Presented at Nematology Symposium held at Coimbatore, India in February, 1981 Abstract In host plants susceptible to Meloidogyne infections, susceptibility being the common factor the degrees of susceptibility reflect the individuality. This individuality centres around the differential mobilization of metabolites, viz. differences in catalysis and synthesis etc., attendant with the pathological metabolism. Two susceptible hosts viz. cowpea (Vigna sinensis) and beans - (Dolichos lablab) infected with 500 juveniles. of M. incognita acrita were analysed for the various metaboli tes, 30 and 60 days after inoculations by adopting the standard procedures. The two different susceptible hosts, exhibited different rates of turn over of the metabolites studied. The shoot system (area remote from the site of infestation) and the galls (site of infestation), seemed to behave independent of each other indicating localized reactions. Taking Cowpea as an example, sugar depletion in the gall on the 30th day was greater than on the 60th day. The shoot registered lesser drop. Protein build up was extensive in the gall indicative of significant synthesis. This was also indicated for the phenols on the 30th day, but on the 60th day, phenols depleted, indicating their differential turn over as infection progressed. The shoot on the contrary registered increments for phenols. The lipids which reduced on the 30th day, registered increments on the 60th day, again, reflecting their differential mobilization, as infestation progressed. The shoots on the contrary, registered drop on both the occasions (30th, 60th days.). Similarly, infested beans also exhibited differential mobilization of the various metabolites, at different intervals in the different areas. Quantitatively the picture of the pathological metabolism for the hosts, was as follows: Cowpea: While catalysis amounted to nearly 75%, synthesis amounted to 1/3rd of catalysis in the root on the 30th day. In the shoot also, synthesis was almost l/3rd of catalysis on the 30th day. Amidst different mobilizations of the various metabolites, the shoot and the root seemed to put up almost an uniform rate of synthesis on the 30th day of infestation. On the 60th day, synthesis in the root amounted to almost four times that of catalysis in the gall, while in the shoot, it was nearly five times that of catalysis. Beans: In the gall synthesis was only 1/4th that of catalysis on the 30th day while in the shoot it was only 1/7th of catalysis. The two regions thus markedly varied in their metabolic turn over on the 30th day. On the 60th day, in the gall, synthesis was almost 1.5 times that of catalysis in the gall while in the shoot it was nearly 2.75 times greater than catalysis. Thus it is seen that, the individual hypersensitive reactions are different, in the two susceptible hosts. Top |