The infection and diseases development of Teratosphaeria destructans on Eucalyptus

Figures-Chapter 1: Main anatomical and molecular responses of Eucalyptus against fungal foliar pathogens.

Figures-Chapter 2: Infection by Teratosphaeria destructans on Eucalyptus leaves viastomata at 3 days after inoculation (dai), followed by a biotrophic phase of intercellular growth for 2 weeks after inoculation (wai), preceded by the appearance of symptoms at 4 wai.

Figures-Chapter 3: Transcriptomic analysis of the host responses at different stages of infection, 3 dai, 2 wai and 4 wai, revealed that hormone signaling, oxidative burst and plant-defense related genes were significantly differentially expressed only at the latest point after inoculation (4 wai). Genes related to the flavonoid pathway were up-regulated at the early and late stage of infection and in contrast genes related to terpenoids biosynthesis pathway were down-regulated at the early stage of infection. In line with these results, in-vitro assays showed that three different flavonoids and the terpenoid, eucalyptol, modulate pathogen germination.

Figures-Chapter 4: Different genotypes of E. grandis x E. urophylla were assessed to determine differences in susceptibility to infection by Teratosphaeria destructans. To achieve this a susceptibility index (SI) was developed with six categories ranging from highly resistant (SI= 0), to highly susceptible (SI= 1.5-2). The disease severity was also measured by using image processing to calculate the percentage of leaf area covered by lesions (PLACL), pathogen infection and sporulation on the host was also correlated.

Figures-Chapter 5: Four different genotypes with contrasting levels of susceptibility were selected for leaf wax analysis to determine the effect of leaf wax compounds on pathogen infection. Two main compounds identified as cycloartenol (CAS) and hexanedioic acid showed to inhibit pathogen germination and palmitic acid showed to promote pathogen germination.