Abundance of genes related to soil phosphorus cycling in a desertification gradient

Abstract

Desertification is the most serious environmental problem occurring in soils in arid and semiarid climate worldwide. Overall, the decrease in soil functional capacity caused by desertification is due to the loss of ecological processes carried out by microbial communities. Therefore, evaluating ecological functions of soil microbial communities could provide essential knowledge to help us to evaluate long-term impact of anthropic actions imposed on the soil system. It is well recognized the lack of information on how desertification can reduce the occurrence of some ecological processes, such as in phosphorus mineralization process. Here, three systems will be considered, i) a desertified area, ii) an exclusion (restored) area, iii) and a native area. We will evaluate the impact of desertification in Caatinga biome on the functional genes related to phosphorus cycling, i.e., phoD and phoC, which encoding to alkaline and acid phosphatase, respectively. We will perform quantitative PCR using the DNA extracted previously in Brazil. The soil sampling was carried out at Irauçuba municipality, Ceará, Brazil, in two seasons (rainy and dry). We will use the native Caatinga biome as a reference area to compare the impact of desertification and exclusion (restored) management. Thus, we will obtain the differential abundance among the areas. In other words, it will be possible to find which genes are enriched or depleted. We expected to show that in overgrazed areas there is a significantly depletion of genes involved in phosphorus mineralization, whilst restored (exclusion areas) there is an enrichment of these genes. (AU)