Beneficial microorganisms associated with sugarcane crops : the green gold for clean energy

Sugarcane is currently the economic basis of more than 100 countries, planted on over 25 million hectares worldwide. It has been considered one of the most promising crops for generating clean and renewable energy and is expected to become the second largest energy source in the world by 2030. The global production of this crop is continuously growing, mostly because of the rising consumption of sugar and ethanol. Increases in both crop area plantations and yield are occurring to meet the growing demand. As sugarcane plants establish associations with a great diversity of microorganisms during their life cycle, the use of beneficial fungi and bacteria as a complementary tool to improve plant yield has arisen as a powerful option to meet the current needs to increase productivity and sustainability. However, despite the economic importance of sugarcane, knowledge regarding the microbial community associated with this crop is still limited, as there is still a lack of information on the real diversity and roles of fungal and bacterial species. Current knowledge on sugarcane mycobiota has revealed Epicoccum, Trichoderma, and arbuscular mycorrhizae fungi as the main beneficial fungal agents with high potential for use as microbial-based biostimulants, leading to positive effects that include growth promotion, plant protection, stress resistance, and improved nutrient acquisition. The most studied plant growth-promoting bacteria (PGPB) associated with sugarcane include representatives of the genera Beijerinckia, Gluconacetobacter, Herbaspirillum, Burkholderia, and Azospirillum. The most significant effect obtained from the interaction of sugarcane with these PGPBs is the reduction of chemical nitrogen fertilizers, as these bacteria are able to convert atmospheric nitrogen into an available source, ammonium. Therefore, the use of microbial inoculants should be maximized in crop production, as there is strong evidence that sugarcane plants are able to grow more efficiently by establishing interactions with beneficial microorganisms. This chapter presents an overview on sugarcane production worldwide and gathers the main information about fungi and bacteria described as beneficial to sugarcane, as well as recent data on its complex microbiome