Rosellinia necatrix infection induces differential gene expression between tolerant and susceptible avocado rootstocks
Fig 6
Comparative model of Rosellinia necatrix infection on susceptible ‘Dusa’ (A) and Tolerant BG83 genotypes (B). 1A. Inoculation of asymptomatic ‘Dusa´plant with wheat grains infected with R. necatrix. 2A. 8 days post inoculation. Visualization of R. necatrix derivative strain CH53-gfp mycelia colonizing the root surface of avocado plantlets without aerial symptoms. The green fluorescent emitted from R. necatrix-gfp was visualized using a fluorescence microscope. Upregulation of genes mainly related to oxidoreduction activity (Redox), cell wall degradation (CWD) as well as potential genes involved in defence to P. cinnamomi (PR) was observed. 3A. 22 days post inoculation. The image shows a radial section of susceptible roots infected with R. necatrix-gfp; penetration and proliferation of R. necatrix mycelia through the root cortex was observed by Confocal Laser Scanning Microscopy (CLSM) concomitant with a decrease in leaf photochemistry (Fv´/Fm´) and gas exchange parameters (AN, gs, E). Expression of genes related with cell wall degradation enzymes (CWD) mainly, chitin related enzymes, become more relevant. 4A. 30 days post inoculation, mild-wilting symptoms of the leaves start to appear in susceptible genotype. CLSM images of radial sections of the roots revealed a profuse invasion of R. necatrix, collapsing vascular vessels. 1B. Inoculation of asymptomatic BG83 plant with wheat grains infected with R. necatrix. 2B. 8 days post inoculation. Visualization of R. necatrix derivative strain CH53-gfp mycelia colonizing the root surface of avocado plantlets without aerial symptoms. 3B. 30 days post inoculation. Asymptomatic tolerant BG83 genotype showing upregulation of genes related to osmotic (OE) and salt stress (SE) as well as genes encoding protease inhibitors (PI).