Desert truffle mycorrhizosphere harbors organic acid releasing plant growth-promoting rhizobacteria, essentially during the truffle fruiting season

Design and Validation of qPCR-Specific Primers for Quantification of the Marketed Terfezia claveryi and Terfezia crassiverrucosa in Soil

Desert truffle crop is a pioneer in southeastern Spain, a region where native edible hypogeous fungi are adapted to the semiarid areas with low annual rainfall. Terfezia claveryi Chatin was the first species of desert truffle to be cultivated, and has been increasing in recent years as an alternative rainfed crop in the Iberian Peninsula. However, its behaviour in the field has yet not been investigated. For this purpose, specific primers were designed for the soil DNA quantification of both T. claveryi and Terfezia crassiverrucosa and a real-time qPCR protocol was developed, using the ITS rDNA region as a target. Moreover, a young desert truffle orchard was sampled for environmental validation. The results showed the highest efficiency for the TerclaF3/TerclaR1 primers pair, 89%, and the minimal fungal biomass that could be reliable detected was set at 4.23 µg mycelium/g soil. The spatial distribution of fungal biomass was heterogeneous, and there was not a direct relationship between the quantity of winter soil mycelium and the location/productivity of desert truffles. This protocol could be applied to tracking these species in soil and understand their mycelial dynamics in plantations and wild areas.

Draft Genome Sequence of Pseudomonas mandelii Strain 29, Isolated from the Desert Truffle Terfezia claveryi

Here, we report the genome sequence of the mycorrhizal helper bacterium (MHB) Pseudomonas mandelii strain 29. This is the genome of an MHB associated with ascocarps of the desert truffle Terfezia claveryi . The genome is complete and consists of 6,302,122 bp and 5,812 predicted protein-coding sequences.

Phosphate-Solubilizing Bacteria Isolated from Phosphate Solid Sludge and Their Ability to Solubilize Three Inorganic Phosphate Forms: Calcium, Iron, and Aluminum Phosphates

Biofertilizers are a key component of organic agriculture. Bacterial biofertilizers enhance plant growth through a variety of mechanisms, including soil compound mobilization and phosphate solubilizing bacteria (PSB), which convert insoluble phosphorus to plant-available forms. This specificity of PSB allows them to be used as biofertilizers in order to increase P availability, which is an immobile element in the soil. The objective of our study is to assess the capacity of PSB strains isolated from phosphate solid sludge to solubilize three forms of inorganic phosphates: tricalcium phosphate (Ca₃(PO₄)₂), aluminum phosphate (AlPO₄), and iron phosphate (FePO₄), in order to select efficient solubilization strains and use them as biofertilizers in any type of soil, either acidic or calcareous soil. Nine strains were selected and they were evaluated for their ability to dissolve phosphate in the National Botanical Research Institute’s Phosphate (NBRIP) medium with each form of phosphate (Ca₃(PO₄)₂, AlPO₄, and FePO₄) as the sole source of phosphorus. The phosphate solubilizing activity was assessed by the vanadate-molybdate method. All the strains tested showed significantly (p ≤ 0.05) the ability to solubilize the three different forms of phosphates, with a variation between strains, and all strains solubilized Ca₃(PO₄)₂ more than FePO₄ and AlPO₄.