Background: The pulse beetle, Callosobruchus chinensis L. is one of the main biotic threats to chickpea in both field and storage in the world. The evaluation of chickpea genotypes for pulse beetle resistance has increased motivation for the identification and application of host plant resistance as a critical component of pest management. Methods: In the present study, different chickpea genotypes were evaluated under laboratory conditions to identify the antixenosis, antibiosis and GC-MS based untargeted metabolomics of promising chickpea genotypes to the C. chinensis. Result: Genotype NBeG1004 (36.61 eggs/100 seeds) was less prone to egg laying, while ICCV14872 (180.45 eggs/100 seeds) was the most preferred. However, maximal developmental periods, minimum per cent adult emergence and growth index was observed in ICCV92944 Genotype HC1 showed substantial resistance with maximum phenolic, flavonoid and protease inhibitors content. The results revealed that presence of 9-Octadecenoic acid (Z) in HC1 conferred resistance to C. chinensis. These results show assurance for incorporation into an IPM program against C. chinensis.

A total of 50 Fusarium isolates were collected from major pigeonpea growing states of India and studied for cultural and morphological characters. Among 50 isolates, a total of 30 isolates were selected based on their cultural and morphological characters and studied for pathogenic variability on eight pigeonpea (ICP8858, ICP 8859, ICP 8862, BDN-2, ICP 9174 ICP 8863, ICP 2376 and BAHAR) differential genotypes. Among eight genotypes, the four genotypes namely ICP8858, ICP 8859, ICP 8862, BDN-2 reacted differentially to isolates and not much consistent in their pathogenicity, however two genotypes ICP 9174 and ICP 8863 exhibited resistant reactions and two genotypes ICP 2376 and BAHAR exhibited consistent susceptibility to wilt disease and could differentiate the 30 Fusarium isolates into six pathogenic variants (0, 1, 2, 3, 4 and 5). Among 6 variants, maximum distribution of Fusarium variants was noticed in Bihar and Telangana (4 variants in each state) followed by Andhra Pradesh, Karnataka Uttar Pradesh and, Maharashtra (2 variants) and one variant each in New Delhi and Jharkhand states. The ITS-rDNA sequencing 23 Fusarium isolates of revealed that Fusarium udum (65.21) was the dominant species causing pigeonpea wilt in India followed by Fusarium solani (21.7) and Fusarium equiseti (13.04). The results of present study were notable in terms of Fusarium variants, which might be used to deploy location specific wilt resistant cultivars for improved disease management tactics. This study will also aid in the development of broad- based pigeonpea wilt resistant varieties to supress potential epidemics.

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Nicotine is a highly addictive alkaloid and a neurostimulator found in tobacco that causes addiction in humans and makes tobacco a high-demand commercial product. It is popularly used for recreational purposes and is a harmful substance (Oral LD50 value for rat is 50 mg/kg) and causes addiction. The metabolites of nicotine such as the Tobacco-specific Nitrosamines (TSNAs) are hazardous substances whose metabolites are highly electrophilic and form DNA adducts, which will initiate the process of carcinogenesis. TSNAs are formed during curing, storage and fermentation due to the nitrosation of nicotine and other tobacco alkaloids. TSNAs are used as biomarkers for cancer risk assessment in humans exposed to tobacco and its products. To determine the occasional formation of TSNAs in tobacco-feeding insects, 5th instar larvae of Spodoptera litura and their faeces were analyzed for the presence of N′-nitrosonornicotine (NNN), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) along with the stored tobacco leaves (PT-76) using an Agilent 6470B LC–MS/MS system following ISO/DIS 19290:2015 protocol. The larvae are extracted in a buffered acetonitrile–water extraction and the amount of TSNAs are quantified in multiple reaction monitoring (MRM) mode. 20 $$\upmu$$ μ l of each extracted and cleaned up sample was injected into the LC–MS/MS system for quantification. The Limit of Detection (LOD) and Limit of Quantification (LOQ) were 0.001 mg/kg and 0.005 mg/kg for all the tested nitrosamines. NNN was found to be 0.361 mg/kg, 0.340 mg/kg, and 5.66 mg/kg in insect whole-body samples, faeces, and tobacco leaves, respectively. NNK was found to be 0.060 mg/kg, 0.035 mg/kg and 0.93 mg/kg in insect whole body samples, faeces and tobacco leaves, respectively. However, NNAL was not detected in both the insect’s whole body and faeces. Recoveries ranged between 95 and 98% for all compounds when spiked at LOD and LOQ. The presence of TSNAs is a biomarker for cancer risk and their presence in insects would point to cancer risk assessment in tobacco feeding insects and any possible TSNA-detoxifying pathways in insects that might prevent mutagenesis caused these compounds.