*2.7. CRY1 Overexpressing Line Is More Resistant to Fire Blight*

Plantlets were observed for 96 h after the inoculation of *E. amylovora* to detect necrotic tissues. Necrosis symptoms appeared only in the shoot apex of *Dar Gazi-wt* plantlets after 36 h from the inoculation (Figure 12). After 96 h, the progress of necrosis that affected the entire stem was visible. In the plantlets of *Dar Gazi-phyB*, necrosis was detected in several leaf nodes throughout the stem only after 48 h from the inoculation (Figure 12). Surprisingly, *Dar Gazi-cry1* plantlets better tolerated the pathogen infection showed necrotic tissues after 72/96 h (Figure 12).

**Figure 12.** Sintomatology of bacterial infection. White arrows indicate the necrotic stem area. **Figure 12.** Sintomatology of bacterial infection. White arrows indicate the necrotic stem area. **Figure 12.** Sintomatology of bacterial infection. White arrows indicate the necrotic stem area.

Gene expression analysis showed that transcript levels of PRs were more significant in photoreceptor over-expressing plantlets than in *Dar Gazi-wt* plantlets, indicating an increased capacity to counteract the infection (Figure 13). At the same time, the expression profile of erw genes indicated that only *erw1*, coding for CAFS, was expressed during the first 12 h after the infection. In addition, erws transcript levels were also greater in plantlets over-expressing photoreceptors than in *Dar Gazi-wt* plantlets, suggesting a dynamic Gene expression analysis showed that transcript levels of PRs were more significant in photoreceptor over-expressing plantlets than in *Dar Gazi-wt* plantlets, indicating an increased capacity to counteract the infection (Figure 13). At the same time, the expression profile of erw genes indicated that only *erw1*, coding for CAFS, was expressed during the first 12 h after the infection. In addition, erws transcript levels were also greater in plantlets over-expressing photoreceptors than in *Dar Gazi-wt* plantlets, suggesting a dynamic interaction occurring during the bacterial invasion of host tissues (Figure 13). Gene expression analysis showed that transcript levels of PRs were more significant in photoreceptor over-expressing plantlets than in *Dar Gazi-wt* plantlets, indicating an increased capacity to counteract the infection (Figure 13). At the same time, the expression profile of erw genes indicated that only *erw1*, coding for CAFS, was expressed during the first 12 h after the infection. In addition, erws transcript levels were also greater in plantlets over-expressing photoreceptors than in *Dar Gazi-wt* plantlets, suggesting a dynamic interaction occurring during the bacterial invasion of host tissues (Figure 13).

**Figure 13.** *PR1*, *PR10*, and *erw1*-*4* expression in *Dar Gazi-wt*, *Dar Gazi-phyB*, and *Dar Gazi-cry1* plants, grown under 16/8 h **Figure 13.** *PR1*, *PR10*, and *erw1*-*4* expression in *Dar Gazi-wt*, *Dar Gazi-phyB*, and *Dar Gazi-cry1* plants, grown under 16/8 h light/darkness, at 12, 24, 36, and 48 h after the pathogen inoculation. Results are presented after normalization with ef1A. Data shown are the average of two biological replicates run in triplicate, with error bars representing SD. **Figure 13.** *PR1*, *PR10*, and *erw1*-*4* expression in *Dar Gazi-wt*, *Dar Gazi-phyB*, and *Dar Gazi-cry1* plants, grown under 16/8 h light/darkness, at 12, 24, 36, and 48 h after the pathogen inoculation. Results are presented after normalization with ef1A. Data shown are the average of two biological replicates run in triplicate, with error bars representing SD.

#### Data shown are the average of two biological replicates run in triplicate, with error bars representing SD. **3. Discussion** Plants have evolved to coordinate their activities with the day-night cycle by Earth's **3. Discussion**

**3. Discussion** Plants have evolved to coordinate their activities with the day-night cycle by Earth's rotation. Direct responses to light and darkness are essential, but, in addition, biological rotation. Direct responses to light and darkness are essential, but, in addition, biological Plants have evolved to coordinate their activities with the day-night cycle by Earth's rotation. Direct responses to light and darkness are essential, but, in addition, biological clocks have evolved to time biological processes. Circadian rhythms result from the interaction between the internal oscillatory system and the receptors of environmental

light/darkness, at 12, 24, 36, and 48 h after the pathogen inoculation. Results are presented after normalization with ef1A.

cues such as photoreceptors that usually help reset the biological clock to a 24-h day-night cycle. Many environmental (i.e., temperature) and internal cues (i.e., starvation) function as zeitgebers for the rhythms, but photoperiod and light quality are among the most important ones in plants. There is no other environmental factor in any climatic region of comparable importance for the immediate control of annual and daily cycles [38].
