Research Projects

Soil-borne pathogens and plant parasitic nematodes in Potato viz., Phytophthora infestans, Rhizoctonia solani, Globodera rostochiensis, G. pallida, Meloidogyne incognita, Pratylenchus sp. reduce crop development and productivity drastically. It costs $14 billion per year and causes 100% yield losses. Nematodes act as a predisposing factor for the entry of soil borne pathogens and result in dangerous disease complexes. Hence, fungus and nematodes cause alarming damage due to the leaching of sugars and salts. In the southern hills (Nilgiris), 75% of the potato is grown in the summer, and the late blight disease is at its peak, which reduces the potato yield. This complex biotic stress forces farmers to use fungicides indiscriminately, which increases cost, exposure concerns, fungicide residues, and other issues that prevent long-term use. Certain Nilgiri potatoes have higher-than-recommended levels of organophosphate, according to toxicological data (FSSAI). Due to new, more virulent pathogen genotypes, consumption of fungicides in potato plants has increased in the last decade (The Hindu, 2020) and the proposed research may explain and regulate it. At present, the Nilgiris potato has no effective eco-friendly management plans to contain the above mentioned biotic stresses. Though the available biopesticides are ruling, a single microbe targeting pathogens and nematodes has to be explored to mitigate the complex issue. Although the identified and ruling bioagents may fail to sustain the potato ecosystem, it is mandated to focus on native antagonists with self sustenance. The bioagents, viz., Trichoderma sp., Pseudomonas sp., Bacillus sp., Paecilomyces sp. etc, were explored, and they targeted only one pathogen, which couldn’t survive in the potato ecosystem, which has a pH of 5.0–6.0. In this context, identification of antagonistic microbes that can grow at an acidic pH is essential to mitigating the complex issue. Current research intends to identify acid-tolerant Chaetoglobosins A and C that produce Chaetomium globsum in the potato ecosystem. Chaetoglobosins are a group of macrocyclic polyketides that like cytochalasins, have a wide range of biological activities.  The compounds secreted from Chaetoglobosins A have potent cytotoxicity against the genus Phytophthora sp. inhibiting sporangia germination, and antifungal activity against R.solani which incites black scurf. The chaetoglobosins A and C-producing C.globosum isolates will be tested on cysts and second-stage juveniles (J2s) and parasitization will be recorded. Antifungal molecules biosynthetic gene clusters, white females in root and cyst, and juvenile populations in soil will be explored. Developing a bioformulation from Chaetoglobosins A and C that produces C.globosum would be a boon to managing this complex problem. The identified strain will be developed as a novel bioformulation and the toxicological, phytotoxicological, studies in respective field trials will be carried out