Acta Physiologiae Plantarum Histochemistry and Gene Expression Using Glycerol in the Pathosystem Musa X Mycosphaerella Fijiensis

Black Sigatoka (SN) is a disease that causes leaf lesions that impede the photosynthesis process, culminating in fruits of poor quality banana. Hence, environmentally correct measures, which can present sustainable control of the disease in the field, are extremely important. Therefore, the objective of this study was to verify glycerol-mediated resistance responses in banana plants of the Grande Naine cultivar susceptible to BS. The experiment was conducted in randomized blocks with 5 treatments, namely: control, 0, 3, 5 and 8% glycerol and three replicates. The severity of the disease after the first symptoms was assessed every seven days. For gene expression analysis, the signal transduction genes (STRANS) and the recognition and signaling genes (KINLRR) and the reference genes, L2MU and 25S, were used. Histochemistry was performed to detect calosis with the aid of relative dyes of lugol and aniline blue. By means of leaf tissue clearing, it was possible to visualize pathogen structures from 72 HAI. In the analysis of calosis, the production of the compound was identified in the first evaluations in all glycerol treatments. The target resistance genes, STRANS and KINLRR, had higher expression in the treatments with 5-8% glycerol. From the results presented, glycerol appears to be a good resistance inducer for banana plants when used at a dose of 5%, but further studies are needed to verify the best time to apply treatments, inoculation, and doses to be used.