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Entomopathogenic fungi (EF) provide a potent biocontrol tool; also, their endophytic behavior has broadened their contribution to integrated pest management (IPM) and crop production. In this work, Beauveria bassiana and Metarhizium brunneum were applied to bread wheat (Triticum aestivum) seedlings to elucidate how fungal colonization influences plant growth and the relative expression of 24 genes involved in hormonal syntheses and plant immune mechanisms. A preliminary assay was used to determine the time needed for fungal colonization and assess its effect on wheat growth. Then, plant material collected at various times after inoculation (viz., 2, 8, 20, and 36 h and 9 and 15 days) was used to investigate gene expression by quantitative reverse transcription PCR (RT-qPCR). During the colonization time, B. bassiana and M. brunneum caused strong downregulation of most genes associated with plant immunity and the synthesis of hormones like auxin, cytokinin, and gibberellin. This effect was concomitant with a slowdown of endophytic-colonization-related plant growth until 19 days postinoculation (dpi). However, the wheat started to recover at 15 dpi, simultaneously with upregulation of auxin- and gibberellin-related genes. The results suggest that the EF trigger induced systemic resistance rather than acquired systemic resistance during early plant-microbe cross talk in wheat. Also, they confirm that the hormone and immune responses of wheat triggered by EF inoculation influenced plant growth, which can be useful with a view to optimizing management of these microorganisms for sustainable agriculture. [ABSTRACT FROM AUTHOR]

BACKGROUND: Zinc (Zn) deficiency in crops is commonly aggravated by high levels of phosphorus (P) in soil. In this work, the initial performance of pot‐growing maize in response to the available P and Zn in soils with low available Zn and to the application of P and Zn fertilizers was investigated. RESULTS: The soils (six non‐calcareous and 14 calcareous) ranged widely in available P (Olsen P: 5.5–37.9 mg kg−1), were poor in available Zn [diethylenetriaminepentaacetic acid‐extractable Zn (ZnDTPA): 0.20–0.84 mg kg−1] and had an Olsen P/ZnDTPA ratio of 13 to 111 mg mg−1. Soil P application generally increased aerial dry matter (ADM) yield; Zn increased ADM yield mostly when applied in combination with P; and the sole application of Zn increased yield only in a soil with a high (28 mg kg−1) Olsen P and a low (0.36 mg kg−1) ZnDTPA. The increase in ADM yield resulting from optimal application of P and/or Zn to the soil was modest in soils where the Olsen P/ZnDTPA ratio was 30–60 and Olsen P was >14 mg kg−1. Zinc uptake by the control plants was correlated with the ZnDTPA of the soil. For a certain ZnDTPA value, the level of plant available Zn was higher in non‐calcareous than in calcareous soils. CONCLUSION: Soil application of fertilizer P and Zn, in soils with low levels of available Zn, should not only aim at increasing the available P and Zn levels but also balancing them at the appropriate Olsen P/ZnDTPA ratio, which was found to lie in the 30–60 range in the present study. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Entomopathogenic fungi (EF) have so far aroused little interest as plant growth promoters or nutritional enhancers while protecting the plant against insect pests and mites. In this work, we examined the performance of Triticum durum and Triticum aestivum plants pot‐grown on two unsterilized Zn‐poor calcareous Vertisols and inoculated with Beauveria bassiana or Metarhizium brunneum by application to soil or seed dressing. The effects of fungal inoculation were found to depend on crop species, soil type, sampling time and fungus application method. While the height of the control plants tended to be significantly greater than the height of inoculated plants at early and intermediate growth stages, the trend changed at more advanced plant stage of development, 56 days after sowing (DAS). This was supported by the significant increase in aerial dry matter (ADM) in T. aestivum plants treated with B. bassiana by seed dressing (17.4%) or with M. brunneum with soil application and seed dressing (20.6 and 26.9%, respectively) 69 DAS. In T. durum, at harvest, seed dressing with B. bassiana or M. brunneum had an overall positive but not significant effect on ADM or grain yield, whereas direct application to the soil slightly decreased grain yield (6.6 and 5.5%, respectively) and ADM (5.3 and 6.1%, respectively). In T. aestivum, none of the fungus–application method combinations affected yield at harvest significantly. Fungal inoculation had little influence on nutrient uptake, whereas application to soil increased Mn uptake and grain Mn concentration in T. durum. Zinc uptake was significantly increased only in T. aestivum grown on the soil with the lowest Zn content treated with M. brunneum. Grain Zn concentration tended to be inversely related to grain yield. These results support seed dressing with EF as a promising green technology for sustainable crop protection and production with no adverse effects on plant performance. [ABSTRACT FROM AUTHOR]

Entomopathogenic fungi (EFs) are widely used as biological control agents. However, some strains of Beauveria bassiana and Metarhizium brunneum can also promote plant growth and increase nutrient uptake. We examined the effects of soil properties on the performance of Triticum durum inoculated by seed dressing with these EFs and grown on 12 agricultural soils. The plants were supplied with all nutrients except P and Zn (essential for yield and the grain quality of wheat). Fungal inoculation increased the grain yield and harvest index significantly with B. bassiana (17% and 14%, respectively) but not with M. brunneum (6% and 6%, respectively). The increase in grain yield was positively and moderately correlated with the soil available phosphorus (POlsen) in plants inoculated with B. bassiana and with the soil content in poorly crystalline Fe oxides with M. brunneum. In addition, the increase in aerial dry matter resulting from inoculation with B. bassiana was negatively correlated with soil available Zn. Furthermore, the observed increase in grain yields due to fungal inoculation resulted in P and Zn grain dilution (grain nutrient concentrations decrease). Inoculation with B. bassiana increased grain Zn uptake and the proportion of Zn in grain relative to that in aerial dry matter. Success in the mutualistic relationship between EF and wheat plants depends on the fungal strain and soil properties. [ABSTRACT FROM AUTHOR]

Purpose: The aims of this work were (i) to find a soil indicator to predict durum wheat yield response to Zn fertilization, (ii) to compare the effect of various Zn fertilization strategies on wheat yield and Zn biofortification in calcareous Vertisols of southern Spain, and (iii) to assess the effect of these Zn fertilization strategies on crop P uptake (durum and bread wheat). Methods: Different Zn fertilization strategies, soil application (0.3–10 kg ha−1) and foliar spraying (two rates, different growth stages), were tested in wheat crops under field conditions in the period 2012–2019. Results: A simple soil indicator failed to predict durum wheat response to Zn fertilization. Only one of the combinations tested increased wheat yield in the 11 field experiments carried out. Zinc foliar spraying (1.28 kg ha−1) was effective for wheat biofortification when applied at early booting (durum wheat) or flowering, and also when splitting this application between stem elongation and flowering stages (bread wheat). The foliar treatments produced the highest zinc use efficiencies (6–19%) and soil applications the lowest (0.2–1.3%). Moreover, foliar treatments increased grain Zn concentrations by 12–51% while soil application increased such concentrations by only 4–13%. None of the Zn fertilization strategies altered P uptake. Conclusion: No yield increase in wheat is expected from Zn fertilization for the application methods and rates used here and the soils studied (calcareous Vertisols under Mediterranean climate). However, foliar applications at and after early booting stage are promising for durum and bread wheat biofortification. [ABSTRACT FROM AUTHOR]

Increasing urbanization worldwide calls for more sustainable urban development. Simultaneously, the global biodiversity crisis accentuates the need of fostering biodiversity within cities. Policies supporting urban nature conservation need to understand people's acceptance of biodiversity‐friendly greenspace management. We surveyed more than 2,000 people in 19 European cities about their attitudes toward near‐natural urban grassland management in public greenspaces, and related their responses to nine sociocultural parameters. Results reveal that people across Europe can support urban biodiversity, yet within the frames of a generally tidy appearance of public greenery. Younger people and those using greenspaces for a greater variety of activities were more likely to favor biodiversity‐friendly greenspace management. Additionally, people who were aware of the meaning of biodiversity and those stating responsibility for biodiversity conservation particularly supported biodiversity‐friendly greenspace management. Our results point at explicit measures like environmental education to increase public acceptance of policies that facilitate nature conservation within cities. [ABSTRACT FROM AUTHOR]