Vicilin has nutraceutical potential and different noteworthy medicative health-promoting biotic diversions, and it is remarkable against pathogenic microorganisms and insects. In this study, Vigna aconitifolia vicilin (VacV) has been identified and characterized from the seed of Vigna aconitifolia (Jacq.) Marechal (Moth beans). LC-MS/MS analysis of VacV provided seven random fragmented sequences comprising 238 residues, showing significant homology with already reported Vigna radiata vicilin (VraV). VacV was purified using ammonium sulfate precipitation (60%) followed by size exclusion chromatography on Hi-Load 16/60 Superdex 200 pg column and anion-exchange chromatography (Hi trap Q FF column). Purified VacV showed a major ~50 kDa band and multiple lower bands on 12% sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) under both reduced and non-reduced conditions. After all, a three-dimensional molecular structure of VacV was predicted, which showed β-sheeted molecular conformation similar to crystallographic structure of VraV. All Vicilins from V. aconitifolia and other plants were divided into six sub-groups by phylogenetic analysis, and VacV shared a high degree of similarity with vicilins of Vigna radiata, Pisum sativum, Lupinus albus, Cicer arietinum and Glycine max. Additionally, VacV (20 μg) has significant growth inhibition against different pathogenic bacteria along strong antifungal activity (50 μg). Likewise, VacV (3.0 mg) produced significant growth reduction in Rice Weevil Sitophilus oryzae larvae after 9 days compared with control. Furthermore, by using MMT assay, the cytotoxicity effect of VacV on the growth of HepG2 liver cancerous cells was tested. VacV showed cytotoxicity against the HepG-2 line and the acquired value was 180 µg after 48 h. Finally, we performed molecular docking against caspase-3 protein (PDB ID: 3DEI) for VacV bioactive receptor interface residues. Hence, our results reveal that VacV, has nutraceutical potential and moth beans can be used as a rich resource of functional foods.

Spodoptera exigua (Hübner) is a polyphagous pest that shifts its population to different hosts during its life cycle to receive nutritive advantages. Therefore, demographic evaluation of alternate hosts is important for effective pest management. Here, we have evaluated castor (Ricinus communis L.), cauliflower (Brassica oleracea L.), cotton (Gossypium hirsutum L.), okra (Abelmoschus esculentus L.), and spinach (Spinacia oleracea L.) for growth, survival, and population development of S. exigua. Development of early populations of S. exigua is best supported on castor where earlier instars had least mortalities (10%) compared with spinach (36%), although later instars and pupae had significantly higher mortalities (20.8%) on it. Spinach and okra, on the other hand, promote larval survivals in later instars. Little or no differences in stadia lengths were observed during early development of larvae and, interestingly, the longevity of female moths increased significantly when reared on castor, cauliflower, and spinach (12.3, 11.3, and 11.7 d, respectively), resulting into significantly higher fecundity. The survival curves of all five populations have clearly demonstrated a steep early decline in larval numbers when reared on okra and only 60% larvae could survive. These findings conclude that S. exigua when fed on spinach was greatly disadvantaged in terms of growth and development; hence, the pest’s field population can be opportunistically controlled by spraying adjacent spinach fields. In addition, the results highlight the vulnerable stages in pest’s life cycle in the field where we can apply integrated control strategies for its effective management.

The role of insecticidal application and host plant resistance in managing Spodoptera exigua has been well documented, but the effect of different host plants, on which the pest cycles its population in the field, has seldom been investigated. Therefore, we have studied the vulnerability of S. exigua against commonly used insecticides (cypermethrin, chlorpyrifos, lufenuron, and emamectin benzoate) with different mode of actions when it switches its generations from natal to auxiliary hosts and vice versa. Different field populations being established on different host plants including castor, cauliflower, cotton, okra, and spinach were collected and reared in the laboratory before insecticidal bioassays. The role of larval diet and host plant switching on their response to tolerate applied insecticides was studied using leaf‐dip bioassay methods. Host switching demonstrated a significant role in altering the vulnerability of S. exigua populations to tested insecticides. Spodoptera exigua sourced from castor, when switched host to okra and spinach, exhibited 50% higher mortality when treated with emamectin benzoate. This trend in mortality was consistent upon complete host switch cycle (natal—auxiliary—natal host). However, the highest increase (92%) in vulnerability was recorded when the larvae were shifted to spinach from cotton. In general, chlorpyrifos and lufenuron had highest efficacies in terms of larval mortality. The findings of present studies provide insights to a better understanding the behavior of polyphagous pests and the role of different host plants in altering the susceptibility of these pests against applied insecticides. Ultimately the results warrant that due consideration should be given to cropping patterns and time of host switching by pest population during planning and executing chemical control.

Background: Fungi and insect pests ruin stored crop grain, which results in millions of dollars of damage, presenting an ongoing challenge for farmers in addition to diminishing the safety of stored food. A wide-range defensive system against pathogens is needed to reduce or even eliminate the dependence of the crop yield upon the use of pesticides. Plant defensins (γ-thionins) are antimicrobial peptides (AMPs) that are a component of the host defense system. They are known to interact with cell membranes to exhibit antifungal and insecticidal activity. They exhibit a broad range of activities against fungi and insects and are effective at low concentrations. Thionins act on membranes, greatly reducing the development of pathogen resistance.Objective: The aim of this study is to investigate a bioactive molecule that acts against fungal pathogens and stored grain insect pests.Method: γ-thionin protein was extracted from Brassica oleracea L. var. capitata f. alba (white cabbage) seed powder in phosphate buffer (100 mM, pH 7.0) and was identified by MALDI-TOF/TOF. The crude extract was subjected to 70% ammonium sulfate saturation followed by gel filtration chromatography. The disc diffusion assay along with a microtiter bioassay was used to determine the antifungal activity of the protein against phytopathogenic fungi. The insecticidal efficacy was evaluated by feeding insect pests with food contaminated with the purified protein. Additionally, an in silico molecular structure prediction study of the protein was performed using Auto Dock Vina for molecular docking of the protein with either fungal membrane moieties or α-amylase from Tenebrio molitor L. MD simulations of protein-ligand complexes were conducted using Schrodinger’s Desmond module.Results: γ-Thionin (BoT) was purified from white cabbage seeds and showed 100% homology with thionin (Brassica oleracea L. var. viridis) and 80% homology with defensin-like protein 1 (Raphanus sativus L.), respectively. BoT significantly inhibited the mycelial growth of Aspergillus niger van Tieghem and Aspergillus flavus Link at a concentration of 2 μM. Similarly, 0.12 μM BoT treatment resulted in significant mortality of Tribolium castaneum Herbst and Sitophilus oryzae L. Molecular docking and MD simulation of BoT confirmed the strong binding affinity with fungal membrane moieties (phosphatidylinositol 4,5-bisphosphate and phosphatidic acid), which causes disruption of the cell membrane and leakage of the cellular contents, leading to cell death. BoT blocked the active site of α-amylase, and as a result of the inactivation of this gut enzyme, the digestive systems of insects were disturbed, resulting in their deaths.Conclusion: This study revealed that γ-thionin is a good antifungal and insecticidal agent that could be used as an alternate to fungicides and insecticides.

Growth and development of insects in the laboratory cultures can be significantly enhanced by improving the nutrient quality of their culturing medium. One way to achieve this is by including add-ons in the food medium. This approach is commonly followed in culturing red flour beetle Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) which is used as a model insect for a variety of laboratory studies. Commonly yeast is used as a food admixture for escalating beetle production and promoting oviposition. In this study, we aim to evaluate some alternates for yeast, i.e. agar-agar and folic acid at three levels (3.33 %, 6.66%and 10 %) for enhancing laboratory culturing of T. castaneum. The results demonstrated that highest adult production was achieved by adding yeast at the rate of 6.66%(279±23.24) to the food medium while agar-agar and folic acid produced more adults albeit with prolonged larval duration of about 5 days as compared to yeast when ad-mixed at rates of 10%(196.6±21.52) and 3.33%(164.8±3.51). The experiment confirms yeast as a best add-on for enhancing the T. castaneum population but agar-agar and folic acid could be used as substitute when the cultures are required to be maintained vitally without fast developments, for maintaining master cultures in the laboratories.