A novel formulation technology for baculoviruses protects biopesticide from degradation by ultraviolet radiation

Biopesticides are biological pest control agents that are viewed as safer alternatives to the synthetic chemicals that dominate the global insecticide market. A major constraint on the wider adoption of biopesticides is their susceptibility to the ultraviolet (UV: 290–400 nm) radiation in sunlight, which limits their persistence and efficacy. Here, we describe a novel formulation technology for biopesticides in which the active ingredient (baculovirus) is micro-encapsulated in an ENTOSTAT wax combined with a UV absorbant (titanium dioxide, TiO2). Importantly, this capsule protects the sensitive viral DNA from degrading in sunlight, but dissolves in the alkaline insect gut to release the virus, which then infects and kills the pest. We show, using simulated sunlight, in both laboratory bioassays and trials on cabbage and tomato plants, that this can extend the efficacy of the biopesticide well beyond the few hours of existing virus formulations, potentially increasing the spray interval and/or reducing the need for high application rates. The new formulation has a shelf-life at 30 °C of at least 6 months, which is comparable to standard commercial biopesticides and has no phytotoxic effect on the host plants. Taken together, these findings suggest that the new formulation technology could reduce the costs and increase the efficacy of baculovirus biopesticides, with the potential to make them commercially competitive alternatives to synthetic chemicals

Using Light to Improve Commercial Value

The plasticity of plant morphology has evolved to maximize reproductive fitness in response to prevailing environmental conditions. Leaf architecture elaborates to maximize light harvesting, while the transition to flowering can either be accelerated or delayed to improve an individual's fitness. One of the most important environmental signals is light, with plants using light for both photosynthesis and as an environmental signal. Plants perceive different wavelengths of light using distinct photoreceptors. Recent advances in LED technology now enable light quality to be manipulated at a commercial scale, and as such opportunities now exist to take advantage of plants' developmental plasticity to enhance crop yield and quality through precise manipulation of a crops' lighting regime. This review will discuss how plants perceive and respond to light, and consider how these specific signaling pathways can be manipulated to improve crop yield and quality

From ozone depletion to agriculture: understanding the role of UV radiation in sustainable crop production

Largely because of concerns regarding global climate change, there is a burgeoning interest in the application of fundamental scientific knowledge in order to better exploit environmental cues in the achievement of desirable endpoints in crop production. Ultraviolet (UV) radiation is an energetic driver of a diverse range of plant responses and, despite historical concerns regarding the damaging consequences of UV-B radiation for global plant productivity as related to stratospheric ozone depletion, current developments representative of a range of organizational scales suggest that key plant responses to UV-B radiation may be exploitable in the context of a sustainable contribution towards the strengthening of global crop production, including alterations in secondary metabolism, enhanced photoprotection, up-regulation of the antioxidative response and modified resistance to pest and disease attack. Here, we discuss the prospect of this paradigm shift in photobiology, and consider the linkages between fundamental plant biology and crop-level outcomes that can be applied to the plant UV-B response, in addition to the consequences for related biota and many other facets of agro-ecosystem processes

What role does UVB play in determining photosynthesis?

Photosynthesis is a key component of plant biology. It is an essential driver of primary carbohydrate biosynthesis and other aspects of metabolism such as the assimilation of nitrogen into organic compounds within the chloroplast. Photosynthesis is a sophisticated process involving complex bioenergetics and a wide range of different molecules, such as proteins, lipids, and light absorbing chromophores. Photosynthesis is therefore sensitive to regulation and perturbation by biotic and abiotic stimuli. One major abiotic environmental stimulus is UVB radiation (280-315 nm), which is a typical component of the light environment. UVB wavelengths are frequently absorbed by component molecules of photosynthesis and such wavelengths have the potential to initiate loss of function and a cascade of damaging consequences, such as the production of reactive oxygen species. UVB is readily absorbed by DNA, causing damaging lesions. In addition, UVB regulates non-specific changes to gene expression and also acts through a specific photoreceptor molecule that can alter gene expression. In terms of photosynthesis itself, there is a requirement for substantial gene expression activity to establish the complex biostructure of the chloroplast (with its contrasting soluble and membrane components) and to maintain component parts by constant turnover, for example, D1 and D2 polypeptide production. Overall, there is substantial potential for UVB-mediated changes to the photosynthetic process

Herbivory and Attenuated UV Radiation Affect Volatile Emissions of the Invasive WeedCalluna vulgaris

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Mesh crop covers improve potato yield and inhibit tomato potato psyllid and blight: The roles of mesh pore size and ultraviolet radiation

Crop losses caused by the tomato potato psyllid (TPP; Bactericera cockerelli) and blight (Alternaria solani; Phytophthora infestans) continue to be major concerns for potato (Solanum tuberosum) growers worldwide, and commercial crops often require frequent use of agrichemicals to maintain tuber yield and quality. Nevertheless, a paradigm shift is unfolding in crop protection where new tools, such as physical barriers and light‐modifying filters, are being used to develop chemical‐free approaches for pest and disease control. In this study, we examined the use of crop covers as a non‐chemical method for controlling TPP and reducing blight in field potatoes. Our study demonstrated that those plants grown under mesh covers exhibited reduced levels of blight, TPP and associated psyllid yellows. Additionally, potatoes grown under mesh covers exhibited increased yield (91.4 ± 6.9 SD t/ha) compared with both uncovered control plants (75.0 ± 11.8 t/ha) and plants grown using agrichemical pest control (84.5 ± 10.8 t/ha). The plants grown under mesh produced fewer smaller tubers, with increased average and maximum tuber size, so that marketable yield (tubers ≥60 g) was also increased (83.5 ± 7.5 t/ha), compared with that achieved for uncovered control plants (60.0 ± 8.3 t/ha) and plants grown using agrichemicals (69.6 ± 9.2 t/ha). A second field experiment suggested that the incidence of TPP foliage damage and the development of blight were lowest when the passage of ambient ultraviolet (UV) radiation through the crop cover was reduced. This hypothesis was supported by a third trial where potatoes grown outdoors in pots exhibited reduced TPP foliage damage and fewer resident TPP when grown under UV‐blocking plastic screens. The results of these experiments suggest that the use of mesh covers offers new opportunities to sustainably protect potato crops both by acting as a physical barrier and by modifying the wavelength of light incident on the crop

The UV-B photoreceptor UVR8 promotes photosynthetic efficiency in Arabidopsis thaliana exposed to elevated levels of UV-B

The UV-B photoreceptor UVR8 regulates expression of genes in response to UV-B, some encoding chloroplast proteins, but the importance of UVR8 in maintaining photosynthetic competence is unknown. The maximum quantum yield of PSII (F v/F m) and the operating efficiency of PSII (Φ PSII) were measured in wild-type and uvr8 mutant Arabidopsis thaliana. The importance of specific UVR8-regulated genes in maintaining photosynthetic competence was examined using mutants. Both F v/F m and Φ PSII decreased when plants were exposed to elevated UV-B, in general more so in uvr8 mutant plants than wild-type. UV-B increased the level of psbD-BLRP (blue light responsive promoter) transcripts, encoding the PSII D2 protein. This increase was mediated by the UVR8-regulated chloroplast RNA polymerase sigma factor SIG5, but SIG5 was not required to maintain photosynthetic efficiency at elevated UV-B. Levels of the D1 protein of PSII decreased markedly when plants were exposed to elevated UV-B, but there was no significant difference between wild-type and uvr8 under conditions where the mutant showed increased photoinhibition. The results show that UVR8 promotes photosynthetic efficiency at elevated levels of UV-B. Loss of the DI polypeptide is probably important in causing photoinhibition, but does not entirely explain the reduced photosynthetic efficiency of the uvr8 mutant compared to wild-type