Induced Resistance against Bipolaris bicolor, Bipolaris sorokiniana and Drechslera tritici‐repentis in Wheat Leaves by Xantham Gum and Heat‐Inactivated Conidial Suspension

Abstract

Foliar‐applied xantham gum, commercially available exopolysaccharides from Xanthomonas campestris pv. campestris bacterial capsule, together with conidial suspension of heat‐inactivated pathogens were tested in relation to their ability to induce local and systemic protection against leaf spot diseases caused by Bipolaris sorokiniana, Bipolaris bicolor and Drechslera tritici‐repentis. Xantham gum preparation and heat‐inactivated conidial suspension were effective in inducing local and systemic protection when applied 48 h before the challenge with the pathogen. Microscopic studies of pathogen development in protected and control leaves indicated that neither germination and appressoria formation nor number of papillae were affected by treatment with xantham gum and heat‐inactivated conidial suspension. Increased activity of β‐1,3 glucanases was correlated with the induction of resistance and showed that protection induced in wheat leaves treated with the fungicide propiconazole presented a different mechanism of action.

Lactobacillus plantarum Exopolysaccharides Induce Resistance against Tomato Bacterial Spot

“…(xanthan gum) and commercial xanthan gum were able to induce plant resistance against Hemileia vastatrix, reducing the disease severity by 92% (Guzzo et al, 1996). These effects were also observed in studies with tomato plants against X. gardneri (Luiz et al, 2015) and in studies with EPS extracted from X. campestris, which induced resistance in wheat plants against Bipolaris bicolor, Bipolaris sorokiniana, and Drechslera tritici-repentis (Bach, 1997;Bach et al, 2003). In the present study, the activation of defense mechanisms have been evidenced by the changes in absorbance rates of leaf extract, concentration of phenolics, such as ascorbic and ellagic acid, and also in PAL and GR activities of plants treated with EPS or ASM.…”

Control of spot blotch in barley plants with fungicide and Bauhinia variegata Linn. leaf extract

“…During the first 24 hours after the inoculation of the pathogen, all plants were kept in a humid chamber (80% relative humidity), at room temperature and in the dark. After that, plants were transferred to the greenhouse and kept at room temperature and 12 hours of light per day (Bach et al, 2003).…”

“…Healthy groups were pulverized using water. Protection level was evaluated 7 days after the inoculation of the pathogen, based on the number of infected leaves in ten plants (Bach et al, 2003). First, second and thirty leaves was removed, separated and submitted to extraction.…”

“…The alternative control can be of induction of resistance in plants or, preventing or restricting the development and multiplication of the pathogen (Kuc, 1987). Inducers or elicitors of resistance have already been evaluated in the control of several diseases of plants with natural products (Guzzo et al, 1993;Benhamou, 1996;Gatz, 1997;Bach et al, 2003;Castro and Bach, 2004).…”

Controle de <em>Bipolaris sorokiniana</em> e rendimento de grãos em cevada após aplicação de elicitores e fungicida

“…Shoem. em trigo (Bach, 1997;Bach et al, 1997a;1997b;; Bipolaris sorokiniana em cevada (Castro et al, 2001;2002;Rodrigues et al, 2002;Castro, 2003;Rodrigues e Bach, 2003;Castro e Bach, 2004); Hemileia vastatrix Berk e Br em café (Guzzo et al, 1993); Pyricularia oryzae Cavara e B. sorokiniana em arroz (Manadhar et al, 1999) e Phytophthora capsici Leonian em pimenta (Hwang et al, 1997). Os objetivos deste trabalho foram avaliar a eficiência dos elicitores alicina e goma xantana e do fungicida epoxiconazole + piraclostrobina no controle de B. sorokiniana em cevada e a influência destes no rendimento e características qualitativas de grãos.…”