Eficiência no uso do fósforo, parâmetros microbiológicos do solo e identificação e caracterização de genes da família das fosfatases ácidas em cafeeiros

Abstract

This work aimed to evaluate the nutritional efficiency regarding phosphorus (P), microbiological parameters of the soil and to identify and characterize genes of the family of acid phosphatases in coffee trees. The experiment was conducted under greenhouse conditions at the Empresa de Pesquisa Agropecuária de Minas Gerais (EPAMIG), located in Lavras, state of Minas Gerais, Brazil. In Chapter 2, the experimental design followed a randomized complete block design, in a 10x2 factorial scheme (10 arabica coffee genotypes and two doses of phosphate fertilization), with four replications. In Chapter 3, the experimental design followed a completely randomized design, in a 2x2 factorial scheme (2 cultivars of arabica coffee and two doses of phosphate fertilization), with three replications. Each experimental plot consisted of one pot with ten liters of soil, with one plant. The soil used in the study was collected from the subsurface layer and did not receive any type of microbiological inoculation. Fertilization was carried out using nutrient solutions. The experiment lasted eight months in the greenhouse. Thereafter, the soil and plant material samples from each plot were collected for analysis. Agronomic, physiological, chemical, microbiological and molecular variables were analyzed. The cultivars Catiguá MG2, MGS Ametista and Sarchimor MG 8840 are neither efficient nor responsive to phosphate fertilization. Progeny H 6-47-10 pl. 3 and the cultivar Catuaí Vermelho IAC 144 are not efficient but are responsive to phosphate fertilization. The cultivars Paraíso MG H 419-1, Topázio MG 1190 and MGS Paraíso 2 are efficient but are not responsive to phosphate fertilization. The cultivars Bourbon Amarelo IAC J10 and MGS Aranãs are efficient and responsive to phosphate fertilization. Phosphate fertilization has a positive influence on the microbial biomass carbon and negatively on mycorrhizal spores density. Genotypes of arabica coffee respond positively both with phosphate fertilization (MGS Ametista) and without phosphate fertilization (MGS Paraíso 2) in acid phosphatase activity. A total of 29 genes of the Purple Acid Phosphatase (PAP) family in the genome of Coffea canephora were identified. In the cultivar MGS Paraíso 2 some PAPs were more expressed under P deprivation (CarPAP3, CarPAP11 and CarPAP18) and others were indifferent to P (CarPAP12). The gene expression of CarPAP18 and the acid phosphatase activity were highly significant in the MGS Paraíso 2 cultivar under P deprivation.