ABSTRACT Vines are highly responsive to agricultural management techniques, such as training systems. Three training systems, i.e., conventional, high, and double training, for the ‘Niagara Rosada’ vine were studied considering aspects related to the yield, physicochemical, and antioxidant characteristics of the grapes. The experiment was carried out during two seasons (2017 and 2018), and the vines grafted on IAC 572 Jales. The training systems did not influence the fruit production per vine and yield of the ‘Niagara Rosada’ table grape, but some improvements were observed, such as a greater number of berries per bunch in vines managed in the conventional training systems and a higher fresh mass of berries when cultivated in the high and double training systems. Grapes from the double training system had higher soluble solids contents, an important sensorial characteristic in table grapes. The high training system, in turn, provided ‘Niagara Rosada’ table grapes with a greater content of bioactive compounds (e.g., phenolic compounds, flavonoids, and anthocyanins) and antioxidant activity.

Lignin, after cellulose, is the second most abundant biopolymer on Earth, accounting for 30% of the organic carbon in the biosphere. It is considered an important evolutionary adaptation of plants during their transition from the aquatic environment to land, since it bestowed the early tracheophytes with physical support to stand upright and enabled long-distance transport of water and solutes by waterproofing the vascular tissue. Although essential for plant growth and development, lignin is the major plant cell wall component responsible for biomass recalcitrance to industrial processing. The fact that lignin is a non-linear aromatic polymer built with chemically diverse and poorly reactive linkages and a variety of monomer units precludes the ability of any single enzyme to properly recognize and degrade it. Consequently, the use of lignocellulosic feedstock as a renewable and sustainable resource for the production of biofuels and bio-based materials will depend on the identification and characterization of the factors that determine plant biomass recalcitrance, especially the highly complex phenolic polymer lignin. Here, we summarize the current knowledge regarding lignin metabolism in plants, its effect on biomass recalcitrance and the emergent strategies to modify biomass recalcitrance through metabolic engineering of the lignin pathway. In addition, the potential use of sugarcane as a second-generation biofuel crop and the advances in lignin-related studies in sugarcane are discussed.