Effect bacterial communication signals of DSF-family on development of angular spot bacterial Xanthomonas citri subsp. malvacearum and defense responses at cotton plant.

Abstract

This research was conducted during 2020-2021. Which aimed to study the effect of the Diffusible Signal Factor (DSF) family-containing extract of culture of the bacteria Xanthomonas citri subsp. malvacerum S101 (Xcm S101) at concentration of 0.5 mg/mL, and the pure DSF signal at concentration of 100 µM in limiting the growth and development of bacteria Xcm S101, and in defense responses in cotton plant.  The results showed a logarithmic decrease in the growth of bacteria Xcm S101 in the plant tissues of the cotyledon leaves of the plant, which were previously injected with the DSF family-containing extract of culture, or the pure DSF signal, were approximately (2.85, 2.19), respectively compared with the control after 4 days of bacterial infection. While the plant tissues of the cotyledons of the cotton plant, which were injected with a suspension containing the DSF family-containing extract of culture, or the pure DSF signal, the Xcm S101 bacteria showed a logarithmic decrease in growth approximately (3.6, 2.54), respectively, compared to the control after 4 days of bacterial infection, and the results also showed an increase in defense responses in cotyledon leaves which treated with both the DSF family-containing extract of culture, or the pure DSF signal as: hydrogen peroxide accumulation and induce the programmed cell death system, and increased the level of peroxidase enzyme, which reached in the 10-day-old cotyledon leaves whose seeds were pre-soaked with the DSF family-containing extract of culture, or pure DSF signal approximately nankatal/mg (94.32, 85.9) compared with the control that reached 37.55 nanKatal/mg, while the 10-day-old cotyledon leaves treated by spraying with the DSF family-containing extract of culture or the pure DSF signal had the peroxidase enzyme level of approximately (104.62, 88.94) nankatak/mg, respectively compared with the control, which reached

63.211 nanKatal/mg at 48 hours after treatment