Abstract
Expansins refer to a family of closely related non-enzymatic proteins found in the plant cell wall that are involved in the cell wall loosening. In addition, expansins appear to be involved in different physiological and environmental responses in plants such as leaf and stem initiation and growth, stomata opening and closing, reproduction, ripening and stress tolerance. Sugarcane (Saccharum spp.) is one of the main crops grown worldwide. Lignocellulosic biomass from sugarcane is one of the most promising raw materials for the ethanol industry. However, the efficient use of lignocellulosic biomass requires the optimization of several steps, including the access of some enzymes to the hemicellulosic matrix. The addition of expansins in an enzymatic cocktail or their genetic manipulation could drastically improve the saccharification process of feedstock biomass by weakening the hydrogen bonds between polysaccharides present in plant cell walls. In this study, the expansin gene family in sugarcane was identified and characterized by in silico analysis. Ninety two putative expansins in sugarcane (SacEXPs) were categorized in three subfamilies after phylogenetic analysis. The expression profile of some expansin genes in leaves of sugarcane in different developmental stages was also investigated. This study intended to provide suitable expansin targets for genetic manipulation of sugarcane aiming at biomass and yield improvement.
Highlights
Plant cell walls are dynamic structures that determine and maintain the size and the shape of the cells and serve as a protective barrier
Three additional sequences were found and characterized as expansin-like A (EXPLA), due to the presence of extension at the C-terminus and absence of the HDF domain [28]. These results suggest a total of 92 expansins or expansin-like sequences in sugarcane, from which 51 were EXPA, 38 EXPB and 3 EXPLA (S1 Table and S1 Fig)
The number of EXPA, EXPB, EXPLA and expansin-like B (EXPLB) found in sugarcane was compared with other available characterized expansins from dicot (Arabidopsis, soybean, tobacco, tomato and potato) and monocot plants
Summary
Plant cell walls are dynamic structures that determine and maintain the size and the shape of the cells and serve as a protective barrier. The cell walls are highly complex structures composed mainly of polysaccharides that vary in structure, function and abundance. Cell walls are composed of proteins, some of them with properties and functions not completely understood. Expansins are cell wall proteins discovered in cucumber hypocotyls that act in the remodeling of the plant wall by breaking the non-covalent links between cellulose microfibrils and polymers in the extracellular matrix in a pH dependent manner, leading to loosening, remodeling, assembly and cell extension [1, 2].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
