Implicações da competição por íons ferro e nitrogênio no controle da mancha-bacteriana do maracujazeiro

Abstract

The passionfruit bacterial blight is one of the major diseases of culture, bringing a significant impact to production. It is postulated that Xanthomonas axonopodis pv. passifiorae (Xap), the causative agent of the disease, requires a minimum density of viable cells in the phylloplane to be able to cause infection. Therefore, it is assumed that previously selected antagonists , who demonstrated ability to control the disease and to compete for iron ions and organic nitrogen sources, reduce the population of Xap by preemptive exclusion. This is the hypothesis to be tested in this work. On this research was defined: the concentration of colony forming units capable of inducing the development of bacterial spot, the effect of competition for iron ions and nitrogen source in the resident population of Xap in phyloplan, the role of competition for iron ions and N source in reduction of the resident population Xap phyloplan, as well as the severity of bacterial spot. With the results obtained, it can be determined that Fe ions were able to interfere with the population density of Xap in phyloplan and severity of the disease, along with sources N.de how the availability of iron ions or organic nitrogen interferes the population density of Xap in phyloplan passion fruit and severity of the disease. Even in situations where it was observed to decrease the bacterial load of Xap due to restricted access to the Fe ion and the source of N, a reduction of disease severity. This information can brings the possibility of developing new disease control methods, either by the use of selected antagonists or the use of molecules that performs the same restrictions on these elements.