In contrast, the activities of chitinases and β-1,3-glucanases were higher in the leaves of the −Si plants probably due to the unlimited M. albescens growth in the leaf tissues, as indicated by the larger lesions. The results of this study highlight the potential of Si in decreasing the expansion of the leaf scald lesions concomitantly with the potentiation of phenolic and lignin production, and the greater activities of POX, PPO, PAL and LOX rather than simply acting only as
a physical barrier to avoid M. albescens penetration. “
“Leaf streak, caused by Xanthomonas translucens pv. undulosa, is the major bacterial disease of wheat in Brazil and other countries worldwide. This study aimed to
ITF2357 order evaluate the effect of silicon (Si) on disease development and the biochemical mechanisms possibly involved in resistance potentialized by this element. Plants of cv. BR-18, susceptible to leaf streak, were grown in plastic pots containing Si-deficient soil amended with either calcium silicate (+Si) or calcium carbonate (−Si). The content of Si increased (P ≤ 0.05) by 96.5% for the +Si when compared with −Si treatment. There was no difference (P ≥ 0.05) between Si treatments for calcium content on leaf tissue, so variations in Si accounted for differences in the level of resistance to leaf streak. There was no difference (P ≥ 0.05) between FK506 cost Si treatments for incubation period, latent period, necrotic leaf area, and severity estimated by the software quant. However, chlorotic leaf area was reduced (P ≤ 0.05) by 50.2% for the +Si when compared with −Si treatment. There was no difference (P ≥ 0.05)
between Si treatments for the bacteria population on leaf tissue; however, the values seemed to be somewhat lower in the +Si treatment from 4 to 8 days after inoculation (d.a.i.) on leaves from plants supplied with Si. There was no difference (P ≥ 0.05) between Si treatments for electrolyte leakage. The concentration of total soluble phenolics and lignin-thioglycolic acid (LTGA) derivatives did not show any apparent signs of increase PJ34 HCl during the course of infection and seemed to be slightly higher on plants not supplied with Si at the most advanced stages of bacterial infection. Chitinase activity was high at the most advanced stages of bacterial infection on leaves from +Si treatment and probably affected bacterial growth on leaf tissue. Peroxidase activity following bacterial infection was not increased by Si, but can be linked with the highest concentration of LTGA derivatives at 12 d.a.i. of plants supplied with Si. Polyphenoloxidase activity did not affect wheat resistance to leaf streak regarding of the Si treatments.