Horizontal pathosystem: resistance factors

Publisher Summary The nonspecific resistance factors in the horizontal pathosystem are divided into axeny and true resistance. Axeny is the resistance that occurs before a pathogen–plant cell contact, and true resistance is manifested after the pathogen contact with the cellular protoplast. The chapter explains how anatomical–morphological resistance factors are affected by plant habitus, downy leaves, structure and arrangement of stomata, and anatomic features of internal plant tissues. It also explains the regulation of ontogenesis and damage reparation in pathogens. Many plant parasites can penetrate into tissues only through wounds, and the rate of suberization of wound surfaces correlates with plant resistance. It also explains the nutrient value of infected organs and tissues. The chemical factors available to the plants for their own defense against diseases are diverse in chemical composition, conditions of production, and mechanisms of toxicity. This chapter discusses the chemical classification of phytoanticipins, which includes phenols, terpenoids, proteins, and amino acids. Plants possess not only chemically diverse defense compounds but also various strategies of their application. Protein inhibitors of viruses are a special group of vegetal antibiotic substances. The antiviral activity of a particular inhibitor is usually tested by mixing it with the viral suspension, the mix is used for inoculation of the leaves of a supersusceptible host plant, and then the number of infection spots that occurs is counted. Plant treatment with ribosome inhibitory proteins (RIPs) some time after the inoculation will not prevent development of the viral infection.