Identification of new regulatory targets for the sprouting process of sugarcane and energy cane

Brazil currently has around 10 million hectares of planted sugarcane. From the biomass harvested, 35.48 million tons of sugar, 28.16 billion liters of ethanol are produced and 25,482 GWh of electricity are generated. These numbers represent the great potential of the sugar-energy sector, however, we still have around 150 million hectares in the country occupied by pastures, much of it with low productivity and with enormous potential to implement a more robust crop resistant to environmental conditions. At this scenario, energy cane stands out, a variety of cane that is mainly characterized by its greater rooting, greater resistance to drought, high biomass production and lower sucrose contents in its juice. Nevertheless, sugarcane and energy cane are planted by vegetative propagation or through pre-sprouted seedlings (PPS), however, a serious problem faced in the field is the low sprouting rate, which for some cultivars reaches less than 80 %. Moreover, this problem is not observed for energy cane. The objective of this work was to evaluate the sprouting and initial development phase of a sugarcane and energy cane. Our data demonstrates that energy cane presents a high sprouting rate, followed by rapid shoot growth, with subsequent root formation in the setts. However, opposite observations are shown in sugarcane, by setts root formation and a slow sprouting speed, followed later shoot growth. Based on this information, we evaluated the metabolic and transcriptional profile of buds during the first 48 hours of growth of an energy cane and sugarcane cultivar. Our metabolomics data demonstrate a high metabolic activity in energy cane buds, with an increase in the levels of reducing sugars, organic compounds related to the phenylpropanoid pathway, lipids and a reduction in amino acid levels. These data demonstrate greater activity of the TCA cycle for energy production for growth. In other hand, for sugarcane we found low metabolic activity, with an increase in glutamate levels, which may be explained by root formation in the stalks. In addition, our transcriptional profile data has shown great changes in both cultivars. The data temporal analysis allowed us to identify the profile of genes that have showed greater variance over time. Interestingly, this profile was different between energy and sugarcane cultivars. In addition, we verified the expression profile over time of important genes related to cell growth and division, axillary bud dormancy, cell wall formation, hormonal signaling and sugars, among other targets. Together, our data demonstrate a difference in the initial metabolism of axillary bud growth of energy cane and sugarcane, as well as molecular targets that can be used for breeding programs and agricultural practices that can optimize the sprouting rate (AU)