Puccinia melanocephala and Salt Stress Modified the Inositol Phosphate and TOR Signalling Pathway in Sugarcane

Sugarcane (Saccharum spp. hybrids) is the primary source of sugar and renewable biofuel energy worldwide. Nevertheless, sugarcane production is affected by different biotic and abiotic stresses. In this work, we analysed the impact of Puccinia melanocephala infection and salt stress on the expression profile of genes related with inositol phosphate synthesis and TOR (Target of Rapamycin) signalling pathway regulation in sugarcane. In this sense, two-month-old plants of rust resistant and susceptible cultivars were infected with P. melanocephala and leaf samples were collected daily during the first seven days post-inoculation. A second group of plants was treated with NaCl, previous to leaf sampled at 2 h and 72 h post-stress, leaf chlorophyll content was measured. Quantitative PCR was used to obtain gene expression profiles. Tctp gene was up-regulated in the rust resistant cultivar suggesting that a component of TOR signalling pathway is involving in early pathogen recognition. Biotic and abiotic stresses modified the transcript profile of Mips2 and Tap46 genes, depending on the sugarcane stress resistance. Our results contribute to a better understanding of stress signalling networks in sugarcane.