Nutrient-Poor Breeding Substrates of Ambrosia Beetles Are Enriched With Biologically Important Elements

Fungus-farming within galleries in the xylem of trees has evolved independently in at least twelve lineages of weevils (Curculionidae: Scolytinae, Platypodinae) and one lineage of ship-timber beetles (Lymexylidae). Jointly these are termed ambrosia beetles because they actively cultivate nutritional “ambrosia fungi” as their main source of food. The beetles are obligately dependent on their ambrosia fungi as they provide them a broad range of essential nutrients ensuring their survival in an extremely nutrient-poor environment. While xylem is rich in carbon (C) and hydrogen (H), various elements essential for fungal and beetle growth, such as nitrogen (N), phosphorus (P), sulfur (S), potassium (K), calcium (Ca), magnesium (Mg), and manganese (Mn) are extremely low in concentration. Currently it remains untested how both ambrosia beetles and their fungi meet their nutritional requirements in this habitat. Here, we aimed to determine for the first time if galleries of ambrosia beetles are generally enriched with elements that are rare in uncolonized xylem tissue and whether these nutrients are translocated to the galleries from the xylem by the fungal associates. To do so, we examined natural galleries of three ambrosia beetle species from three independently evolved farming lineages, Xyleborinus saxesenii (Scolytinae: Xyleborini), Trypodendron lineatum (Scolytinae: Xyloterini) and Elateroides dermestoides (Lymexylidae), that cultivate unrelated ambrosia fungi in the ascomycete orders Ophiostomatales, Microascales, and Saccharomycetales, respectively. Several elements, in particular Ca, N, P, K, Mg, Mn, and S, were present in high concentrations within the beetles’ galleries but available in only very low concentrations in the surrounding xylem. The concentration of elements was generally highest with X. saxesenii, followed by T. lineatum and E. dermestoides, which positively correlates with the degree of sociality and productivity of brood per gallery. We propose that the ambrosia fungal mutualists are translocating essential elements through their hyphae from the xylem to fruiting structures they form on gallery walls. Moreover, the extremely strong enrichment observed suggests recycling of these elements from the feces of the insects, where bacteria and yeasts might play a role.

Relationship between Seed Morphological Traits and Ash and Mineral Distribution along the Kernel Using Debranning in Durum Wheats from Different Geographic Sites

Debranning was applied to durum wheat to the study the relationship between kernel shape and size, and ash and mineral distribution having implications for semolina yield. To this aim four durum wheat genotypes carried out over three environments were selected to determine the morphological and yield traits as well as the distribution along the kernel of the ash, macro- (Na, K, P, Ca, and Mg), and micro-elements (Mn, Fe, Cu, Zn, and Mo). A descendent ash gradient within the kernel reflects the decreases in the minerals that occurred during debranning. Perciasacchi with high seed weight (TKW) and greater thickness followed by Cappelli showed a more uniform distribution of ash content along the kernels. High r Pearson coefficient (p < 0.01) showed an inverse relationship between thickness and ash decay. Since thickness was strongly affected by the genotype, it could represent a useful trait for breeding programs to predict the milling quality.

A comparative study on proximate and mineral composition of coloured potato peel and flesh

BACKGOUND

Potato peels are usually discarded before consumption of the tubers. However, it could be expected that red- and purple-fleshed potato peels contain more minerals. Therefore, the purpose of the study was to evaluate and compare the proximate and mineral composition in flesh and peels of six coloured potato cultivars. Five proximate compositions (dry matter, total soluble solids, protein, fibre, and ash) and nine minerals [phosphorus (P), calcium (Ca), magnesium (Mg), potassium (K), iron (Fe), zinc (Zn), copper (Cu), Boron (B), manganese (Mn)] content were determined. The data obtained were evaluated employing the multivariate analysis techniques: principal component analysis and hierarchical cluster analysis.

RESULTS

The results show that proximate and mineral composition depends on potato tissue and cultivar. Potato peels have significantly higher levels of protein, fibre, ash and minerals (except Mg) than the flesh. However, flesh contains the highest contents of dry matter and total soluble solids. Of the studied elements, K has the highest content in both parts of the potato tuber followed by P, Mg, Ca, Fe, Zn, B, Mn, and Cu. Violetta peels had the highest contents of ash, K and Mg, and Highland Burgundy Red peels had the highest protein, fibre, Ca, Mn contents. The flesh of the Highland Burgundy Red cultivar shows the highest contents of dry matter and total soluble solids.

CONCLUSION

Based on the present study, it can be concluded that the investigated red and purple potato peels showed significantly higher protein, fibre, ash and element (K, Ca, Mg, P, Fe, Cu, Zn, Mn, B) contents compared to the flesh. © 2019 Society of Chemical Industry.