Saad Abdulrahman Alamri

Plant resources have been used by humans for their wellbeing for ages. Tribal communities live in far flung areas in close proximity with forests and have a rich cultural heritage and traditional knowledge of forest resources. The present study was carried out in the Rajouri district of Jammu and Kashmir to document the traditional knowledge of plant usage and local perception towards biodiversity conservation. A total of 86 informants were selected through non-probability sampling using a convenience sampling method based on easy access, availability and relevance of informants. During the present study, a total of 92 plant species belonging to 85 genera and 57 families were recorded. Fabaceae and Rosaceae were found to be dominant families. In terms of growth forms, herbaceous species were dominant, followed by trees. Leaves were the most common parts used, followed by fruits. These plant species are used for different purposes such as medicine, edibles, fodder and dye making. A number of plant species were found to be multipurpose in use. Most of the documented plant species are collected by local people from the wild. Local people perceived that the populations of many species, such as Dolomiaea costus, Dioscorea deltoidea and Dolomiaea macrocephala, have declined in recent decades. Climate change, urbanization, deforestation, pollution, overexploitation and species invasion are some of the major threats to biodiversity perceived by the local people. Therefore, the establishment of protected areas and cultivation of wild species are recommended to safeguard forest wealth of the area. Furthermore, mass awareness and cooperation-building programs are highly recommended so that locals can enthusiastically participate in conservation and management programs.

The mechanism underlying the mediation of the behavior and fitness of non-vector herbivores by fungal pathogen-infected host plants is still unclear. In this study, we experimentally assessed the effects of tomato (Lycopersicon esculentum L.) plant infection status on non-vector herbivores using tomato powdery mildew disease fungus (Oidium lycopersici) and the greenhouse whitefly Trialeurodes vaporariorum as a model multitrophic plant-pathogen, non-vector herbivore interaction. In behavioral bioassays, powdery mildew-infected plants (PM) and plants damaged by combined attack of powdery mildew and whiteflies (PMWF) attracted significantly more whiteflies (32.6% and 58.1% for PM and PMWF, respectively) than control (Con) plants (16.5%) or plants damaged only by whiteflies (WF) (24.2%). Whiteflies feeding on PM or PMWF plants secreted almost twice as much honeydew as on the Con or WF plants. This indicated that whiteflies fed more on diseased plants than healthy plants. However, the preferences and increased feeding did not increase the fitness and immature growth of T. vaporariorum, but significantly prolonged their immature developmental durations, compared with those of whiteflies that developed on Con plants or WF plants. The results showed that powdery mildew infestation attracted more whiteflies but reduced their development and fitness.

This investigation explains the green synthesis, characterization and biocontrol potential of copper oxide nanoparticles (CuONPs) against second-stage juveniles (J2s) of root-knot nematode, Meloidogyne incognita infesting chickpea. Mono-disperse, spherical, pure CuONPs were synthesized from Jatropha curcas leaf with particle sizes ranging from 5 to 15 nm in diameter. Antagonistic activities of synthesized CuONPs were studied against Meloidogyne incognita. The highest mortality of J2s was found in the 200 ppm concentration of CuONPs at 24 h of exposure. The exact concentration also showed maximum inhibition of J2s hatching from egg masses after six days of exposure. It was worth noting that 25 ppm concentration was the least effective. The pot experiment showed that CuONPs significantly reduced the root infection caused by M. incognita and enhanced chickpea plants’ growth and physiological attributes (Chlorophyll and carotenoid content). The results depicted when the concentration of CuONPs was increased, J2s mortality rate was also increased. We highlighted the antinematode influence of green synthesized CuONPs. Thus, it will offer an excellent eco-friendly strategy to optimize yield under pathogens attack and provide prospects of green synthesized-based nanoparticles development for pests control. Plants mediated CuONPs will also help in resolving the current toxicity concerns and future challenges in the agriculture. GRAPHICAL ABSTRACT

This study was planned to investigate the efficacy of various concentrations of Trichoderma virens against Meloidogyne incognita in vitro. The five concentrations viz., S, S/2, S/ 10, S/25, S/50 were prepared and planned for in vitro study to test the potential of T. virens against hatching and mortality of second-staged juveniles of M. incognita. It was observed a reduction in second-staged juveniles hatching within all tested aqueous concentrations of T. virens. The second-stage juvenile mortality was also recorded in the above-given concentrations of T. virens. The maximum decrease in second-stage juveniles hatching was found in standard aqueous fungal concentration (S). Moreover, in the same T. virens concentration (S), mortality of juveniles was also recorded as highest, and was followed by S/2, S/10, S/25 and S/50. Additionally, the application of T. virens as an individual, simultaneous, and sequential order with M. incognita was also investigated in pot-grown chickpea plants and found that its use was significantly effective in suppressing root-galling disease and improved the plants' growth and physiological attributes. According to the correlation coefficient analysis, the root-knot index correlated significantly with the per cent reduction of the plants' growth and physiological attributes.

Wheat leaf rust is one of the world’s most widespread rusts. The progress of the disease was monitored using two treatments: chitosan nanoparticles and salicylic acid (SA), as well as three application methods; spraying before or after the inoculation by 24 h, and spraying both before and after the inoculation by 24 h. Urediniospore germination was significantly different between the two treatments. Wheat plants tested for latent and incubation periods, pustule size and receptivity and infection type showed significantly reduced leaf rust when compared to untreated plants. Pucciniatriticina urediniospores showed abnormalities, collapse, lysis, and shrinkage as a result of chitosan nanoparticles treatment. The enzymes, peroxidase and catalase, were increased in the activities. In both treatments, superoxide (O₂⁻) and hydrogen peroxide (H₂O₂), were apparent as purple and brown discolorations. Chitosan nanoparticles and SA treatments resulted in much more discoloration and quantitative measurements than untreated plants. In anatomical examinations, chitosan nanoparticles enhanced thickness of blade (µ), thickness of mesophyll tissue, thickness of the lower and upper epidermis and bundle length and width in the midrib compared to the control. In the control treatment’s top epidermis, several sori and a large number of urediniospores were found. Most anatomical characters of flag leaves in control plants were reduced by biotic stress with P. triticina. Transcription levels of PR1-PR5 and PR10 genes were activated in chitosan nanoparticles treated plants at 0, 1 and 2 days after inoculation. In light of the data, we suggest that the prospective use of chitosan nanoparticles might be an eco-friendly strategy to improve growth and control of leaf rust disease.

Rust, induced by the fungus Uromyces appendiculatus, is one of the most serious bean diseases. The involved mechanisms in rust resistance were evaluated in 10 common bean genotypes during the 2019/2020 and 2020/2021 growing seasons. The disease parameters such as final rust severity (FRS%), area under the disease progress curve (AUDPC) and disease increase rate (r-value) were lower in the resistant genotypes than in highly susceptible genotypes. Biochemical compounds such as total phenols and the activity of antioxidant enzymes such as catalase, peroxidase and polyphenol oxidase were increased in the resistant genotypes compared to susceptible genotypes. In the resistance genotypes, the levels of oxidative stress markers such as hydrogen peroxide (H₂O₂) and superoxide (O₂^•−) increased dramatically after infection. The electrolyte leakage percentage (EL%), was found to be much greater in susceptible genotypes than resistant genotypes. The resistant gene SA14, which was found in genotypes Nebraska and Calypso at 800 bp, had an adequate level of resistance to bean rust with high grain yield potential. After infection, the transcriptions levels of 1,3-D-glucanases and phenylalanine ammonia lyase) were higher in the resistant genotypes than susceptible genotypes. In conclusion, the resistant genotypes successfully displayed desirable agronomic traits and promising expectations in breeding programs for improving management strategies of common bean rust disease. The resistance was mediated by antioxidant enzymes, phenolic compounds, and defense gene expressions, as well as the resistant gene SA14.

The soil-borne pathogens Rhizoctonia solani and Sclerotium rolfsii have emerged as major pathogens of radish (Raphanus sativus) worldwide. The induction of soil suppressive of radish root rot disease was evaluated in soil repeatedly inoculated with R. solani, nonpathogenic binucleate Rhizoctonia sp. AG-A W1 (BNR) and S. rolfsii. The repeated inoculations of soil with R. solani and BNR significantly suppressed the disease severity of R. solani and S. rolfsii compared to the control. In contrast, the repeated inoculation of soil with S. rolfsii significantly suppressed only the pathogen, S. rolfsii. The community structure was examined using PCR-DGGE (polymerase chain reaction denaturing gradient gel electrophoresis) method. The bands of Trichoderma sp. were observed in the first, second and third inoculations of the soil with BNR. Similarly, bands of Trichoderma sp. were observed in the second and third inoculations of the soil with S. rolfsii and R. solani. Compared to the control, disease severity was significantly reduced in the soil repeatedly inoculated with S. rolfsii and R. solani . In conclusion, Trichoderma species were accumulated in specific patterns depending on the applied fungal inoculum in the suppressive soil.

The aim of this study was to investigate the feasibility of using sewage sludge (SS) biosolids as a low-cost soil fertilizer to improve soil characteristics and crop yields. Okra (Abelmoschus esculentus (L.) Moench) plants were grown in soil supplemented with different concentrations of SS (0, 10, 20, 30, 40, and 50 g/kg). The results showed that SS soil application led to improved soil quality with a 93% increase of organic matter (at SS dose of 10 g/kg), decreased pH (a reduction from 8.38 to 7.34), and enhanced macro- and micro- nutrient contents. The levels of all the investigated heavy metals (HMs; Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in the postharvest SS-amended soil were within the prescribed safe limits. The application of SS to soil considerably enhanced the growth parameters of okra plants. Total biomass increased 13-fold and absolute growth rate increased 10-fold compared to plants grown in nonamended (control) soils. Among the applied SS doses, the 10 g/kg SS dose led to the highest values of the measured growth parameters, compared to those of plants grown in control soils. The induced growth at 10 g/kg SS was accompanied by a substantial increase in metal content in roots, stems, leaves, and fruits; however, all levels remained within safe limits. Consequently, the data presented in this study suggest that SS could be used as a sustainable organic fertilizer, also serving as an ecofriendly method of SS recycling.