Wpływ metody inokulacji roślin kukurydzy patogenami bakteryjnymi na powstawanie i rozwój objawów chorobowych

Abstract

The basis of phytopathological diagnostics are Koch’s postulates, the fulfillment of which allows determining whether the examined microorganism is the cause of a given disease. The third of these postulates specifies that inoculation of a healthy host plant with a pure culture of the putative pathogen must result in the induction of disease symptoms similar or the same to those occurring in natural con¬ditions. To meet Koch’s third postulate, a pathogenicity test result is required, and incorrect interpretation may lead to rejection of cor¬rect results. Many years of research on bacteriosis of crop plants, including corn, have shown that the symptoms of the disease resulting from inoculation with the tested strain of bacteria may vary, depending on the inoculation method used and the incubation conditions of the inoculated plants. The conducted research determined the impact of various methods of inoculating corn plants with selected strains of pathogenic bacteria isolated from diseased corn plants on the occurrence and development of disease symptoms. These strains belonged to the species Pectobacterium carotovorum subsp. carotovorum, Dickeya zeae, Pantoea ananatis, Pantoea agglomerans and Enterobacter cloaceae subsp. dissolvens. It was observed that the symptoms of the disease caused by the inoculation methods used dif¬fer from the symptoms observed in natural conditions. Moreover, regardless of the species affiliation of the tested bacterial strains, the observed symptoms were similar within a given inoculation method. Also, regardless of the species affiliation of the tested strain, incuba¬tion of inoculated plants in a culture chamber with optimal conditions for the development of the disease resulted in the acceleration of symptoms and disease development.