ABSTRACT
The plant parasitic nematodes infect the root tissues of the plant causing root galls that lead to reduced water and mineral uptake in the plant root system. Nematophagous fungus are used as biocontrol for the nematodes. Among those Nematoctonus are one of the species used as bioagent. Nematoctonus species produces an extensive mycelium and capture many nematodes with hour glass shaped adhesive knobs on the hyphae. Nematodes become attached to these adhesive knobs and the cuticle of nematode is penetrated by the infective hyphae. This isolate of Nematoctonus robustus is characterized by hyaline mycelium, dikaryotic in nature containing genetically two different nuclei in each cell, having distinct clamp connection. The fungus has better colonizing ability on natural solid substrates like wheat straw and rice straw. It also show good ability to colonize on different cereal grains and various other waste products like coconut coir and FYM etc. This species is one of the best used for mass production and effective for control of plant parasitic nematodes.
ABSTRACT
The survival of sclerotia stored under different conditions revealed that when they were kept in laboratory survived fully up to 7 months. However in soil at 5 cm and 10 cm depth, it survived 100 percent up to 8 and 10 months. The pathogen was viable in the sclerotial form for 17 months in the lab conditions however; it survived for 19 months and 20 months when kept at 5 cm and 10 cm depth in soil respectively. The survival of pathogen along with plant debris stored under different conditions revealed that it survived fully up to 3 months under lab conditions. However in soil at 5 cm and 10 cm depth, it survived 100 percent up to 5 and 6 months respectively. The pathogen survived in diseased plant debris for 9 months in lab conditions. However, the pathogen survives in plant debris up to 11 months and 13 months when kept at 5 cm and 10 cm depth of soil respectively. The viability of pathogen in plant debris was lost gradually. This states sclerotia and plant debris served as source of primary inoculum. Out of fourteen plant species belonging to three families tested, the pathogen produced disease symptoms on all the tested plants and stating pathogen has wide host range.
ABSTRACT
Acacia nilotica proteinase inhibitor (AnPI) was isolated by ammonium sulphate precipitation followed by chromatography on DEAE-Sephadex A-25 and resulted in a purification of 10.68-fold with a 19.5% yield. Electrophoretic analysis of purified AnPI protein resolved into a single band with molecular weight of approximately 18.6+1.00 kDa. AnPI had high stability at different pH values (2.0 to 10.0) except at pH 5.0 and are thermolabile beyond 80°C for 10 min. AnPI exhibited effective against total proteolytic activity and trypsin-like activity, but did not show any inhibitory effect on chymotrypsin activity of midgut of Helicoverpa armigera. The inhibition kinetics studies against H. armigera gut trypsin are of non-competitive type. AnPI had low affinity for H. armigera gut trypsin when compared to SBTI. The partially purified and purified PI proteins-incorporated test diets showed significant reduction in mean larval and pupal weight of H. armigera. The results provide important clues in designing strategies by using the proteinase inhibitors (PIs) from the A. nilotica that can be expressed in genetically engineered plants to confer resistance to H. armigera.