Ultrastructure of the Epidermal Cell Wall and Cuticle of Tomato Fruit (Solanum lycopersicum L.) during Development

Abstract

The epidermis plays a pivotal role in plant development and interaction with the environment. However, it is still poorly understood, especially its outer epidermal wall: a singular wall covered by a cuticle. Changes in the cuticle and cell wall structures are important to fully understand their functions. In this work, an ultrastructure and immunocytochemical approach was taken to identify changes in the cuticle and the main components of the epidermal cell wall during tomato fruit development. A thin and uniform procuticle was already present before fruit set. During cell division, the inner side of the procuticle showed a globular structure with vesicle-like particles in the cell wall close to the cuticle. Transition between cell division and elongation was accompanied by a dramatic increase in cuticle thickness, which represented more than half of the outer epidermal wall, and the lamellate arrangement of the non-cutinized cell wall. Changes in this non-cutinized outer wall during development showed specific features not shared with other cell walls. The coordinated nature of the changes observed in the cuticle and the epidermal cell wall indicate a deep interaction between these two supramolecular structures. Hence, the cuticle should be interpreted within the context of the outer epidermal wall.

The glycerol-3-phosphate acyltransferase GPAT6 from tomato plays a central role in fruit cutin biosynthesis

“…Studies of tomato cuticles span many different fields, ranging from the analysis of cuticle composition and architecture (Mintz-Oron et al, 2008;Buda et al, 2009;Yeats et al, 2012a;Philippe et al, 2016;Segado et al, 2016), biosynthetic pathways, assembly and regulation (Shi et al, 2013;Lashbrooke et al, 2015), interaction with other metabolic pathways and developmental processes (Kosma et al, 2010;Giménez et al, 2015), mechanical properties (Schreiber, 2010;España et al, 2014), as well as the significance of the cuticle for agronomically important traits such as fruit glossiness, postharvest shelf-life, fruit cracking, and resistance to pathogens Shi et al, 2013;Buxdorf et al, 2014;Petit et al, 2014). Considerable progress has been made through reverse genetics approaches, where the function of a candidate gene previously identified is studied in planta in tomato (Girard et al, 2012).…”

“…Cuticle properties also undergo profound changes during the cell expansion phase and are affected by cuticle composition, such as the accumulation of flavonoids (España et al, 2014). In addition to the cuticle, the cell wall plays a critical role in the differentiation and maturation of the fruit epidermis, and the cutin-polysaccharide ratio has been suggested to modulate the cuticle viscoelastic deformation necessary for fruit enlargement (Bargel and Neinhuis, 2005;Segado et al, 2016). The changes that we observed in the exocarp transcriptome of gpat6-a were associated with cuticle, phenylpropanoid, flavonoid, and cell wall biosynthesis and modification (Table IV), which is consistent with the remodeling of fruit epidermal cell walls and the overlying cuticle.…”

“…Cutin may be bound to cell wall polysaccharides; however, the nature of this hypothetical linkage(s) and the coordination of the synthesis of both types of polymers during organ growth are poorly understood (Segado et al, 2016). The cutin matrix is filled with intracuticular waxes and also covered with a thin layer of epicuticular waxes (Nawrath, 2006;Buschhaus and Jetter, 2011).…”

Kinetic study of mass transfer in different parts of Chinese cabbage during brining

“…The main reason for this may be the different structures of epidermal cells in the three different parts of baechu leaves. The leaf epidermis consists of one layer of closely arranged, irregular cells with a thick cuticular membrane on the outer cell wall that can protect tissues against various environmental influences (Segado, Domínguez, & Antonio, ). Moreover, cuticular membrane thickness is highly affected by the growth environment (Mommer, Thijs, Mieke, Jan, & Eric, ).…”

“…FIGUR E 4 Reduced driving force (1 -Y NaCl ) versus t 0.5 in different parts leaves of baechu (n 5 3) ZHAO AND EUN | 5 of 7 cells with a thick cuticular membrane on the outer cell wall that can protect tissues against various environmental influences (Segado, Domínguez, & Antonio, 2016). Moreover, cuticular membrane thickness is highly affected by the growth environment (Mommer, Thijs, Mieke, Jan, & Eric, 2005).…”