At 48 hpi, we also observed electron dense deposits on the mitochondria membrane. On the other hand, HrcC- infection only induced weak cerium deposits on the cell wall at 48 hpi. Cell enlargement is often associated with increased nuclear DNA content. To test if this is the case for the enlarged cells, we embedded the tissue showing chlorotic protrusions with paraplast and stained the sections with DAPI to show nuclei. Compared with mock-treated leaf cells, we found that the enlarged cells induced by DG34 and HrcC- showed much larger nuclei. Images of typical nuclei from guard cells, mesophyll cells, and large cells were shown side-by-side with a higher magnification to illustrate the size difference. We further quantified the relative fluorescence unit of the stained nuclei with ImageJ. Based on the RFU Ginsenoside-Rh1.png)
of nuclei and the assumption that the nuclear DNA content of a guard cell is 2C, we derived the relative nuclear DNA content of the enlarged cells. We found that the enlarged cells have an average of 50C nuclear DNA content, much larger than those of the normal mesophyll cells in mock-treated leaves. The nuclei contents of guard cells and normal mesophyll cells from infected leaves were comparable to those from the corresponding cells in mock-treated leaves. Such an increase in DNA content of the host cells upon infection is possibly due to the activation of endoreplication, a process involving DNA replication without subsequent mitosis. In this report, we systematically examined phenotypes associated with PTI, ETS, and ETI in a time course, including SA accumulation, PR1 expression, cell death formation, and H2O2 production/Lomitapide Mesylate localization. Our data show dynamic changes of these defense related phenotypes during PTI, ETS, and ETI. They also suggest that the differences Pancuronium dibromide between ETS and ETI are dependent on the doses of the strains used. While our data corroborate the quantitative nature of the biological system, they have also revealed the qualitative differences among PTI, ETS, and ETI, in terms of H2O2 localization. Interestingly, we also observed a differential regulation of cell fate during PTI, ETS, and ETI. Thus, the biological system is complicated; it involves not only a large set of common phenotypes induced by various pathogens with different quantities and kinetics, but also distinct responses to specific pathogens. It is generally believed that PTI is a slow and low mode of defense in the host, ETI is an amplified version of PTI, and host defense is suppressed during ETS. Consistent with this notion, we found that the rate of SA accumulation, PR1 expression, and cell death, is faster during ETI than during ETS, when we used a higher dose of DG3 and DG34 to infect plants. However, with a lower dose of the strains, we found that ETI and ETS behave grossly similarly in terms of SA accumulation, PR1 expression, and cell death at early time points. Therefore these results indicate that the differences between ETI and ETS are dependent on the doses of strains used. Our data further show that the differences between ETI and ETS are kinetic. The levels of SA and PR1 transcripts and the severity of cell death are comparable between ETI and ETS or are even higher during ETS than during ETI at later time points. Such dynamic and dose-dependent defense responses suggest that cautions should be taken when comparing plants for their defense phenotypes. For instance, one should use different doses of pathogens to infect plants and sample infected tissue at different time points in order to detect differences in plant defense responses.