Redefining the dose of the entomopathogenic fungus Metarhizium brunneum (Ascomycota, Hypocreales) to increase Fe bioavailability and promote plant growth in calcareous and sandy soils

Soil Nutrients Effects on the Performance of Durum Wheat Inoculated with Entomopathogenic Fungi

“…The increased number of grains, grain yield and harvest index observed here, especially in plants inoculated with B. bassiana, is suggestive of the stimulation of reproductive organs. Similar results were previously obtained with Helianthus annuus [10] and Triticum aestivum [12] grown on soils inoculated by the same EF strains used here. However, the former experiment was ended before the sunflowers reached maturity, and the latter was performed under different conditions (pre-germinated seeds, sterilized sandy soil and high fertilizer levels).…”

“…This could explain the temporal reduction in plant height (at 39 DAS for B. bassiana; Figure S1) and the number of tillers (Table 2) relative to the Control plants in the first phenological stages but not at harvest (no significant reduction in ADM or grain yield). This negative initial effect or cost of fungal inoculation on plant growth was also observed by other authors [10,12,13] and could have been caused by the activation of the defensive mechanism of the host plants [34]. Consistent with this last claim, the increase in grain yield was related to Mn, a key nutrient in the plant immune system [35,36].…”

“…Success in the mutualistic relationship between EF and wheat plants depends on the fungal strain and soil properties. been investigated as plant growth promoters [10-12] and nutritional enhancers [10,[13][14][15][16]. Although B. bassiana, M. brunneum or both fulfill the expectations of most studies, these studies were largely conducted under conditions far from typical field settings.…”

“…Although B. bassiana, M. brunneum or both fulfill the expectations of most studies, these studies were largely conducted under conditions far from typical field settings. In fact, a number of studies were performed on sterile soils or artificial substrates; the effects of the fungi were only examined during early crop growth stages [10,11,13], so neither potential interactions with crops grown on natural soils nor their effects throughout the crop cycle were considered. In addition, although some physical soil properties are known to affect the availability, mobility and virulence of EF conidia in soil [17], there is a knowledge gap on the role that physical and chemical soil properties play in the crosstalk between EF and plants.…”

“…Calero) was chosen because it is a staple crop cultivated worldwide with relevant importance in the Mediterranean belt, including southern Spain where the agricultural soils were collected. Furthermore, durum wheat is a good candidate for this study because its susceptibility to endophytic colonization by EFs was previously reported [10,12] to improve plant growth [12] and Fe uptake [13].…”