The ratio of trichomes to stomata is associated with water use efficiency in Solanum lycopersicum (tomato)

Abstract

Trichomes are specialised structures that originate from the aerial epidermis of plants, and play key roles in the interaction between the plant and the environment. In this study we investigated the trichome phenotypes of four lines selected from the Solanum lycopersicum × Solanum pennellii introgression line (IL) population for differences in trichome density, and their impact on plant performance under water-deficit conditions. We performed comparative analyses at morphological and photosynthetic levels of plants grown under well-watered (WW) and also under water-deficit (WD) conditions in the field. Under WD conditions, we observed higher trichome density in ILs 11-3 and 4-1, and lower stomatal size in IL 4-1 compared with plants grown under WW conditions. The intrinsic water use efficiency (WUE ) was higher under WD conditions in IL 11-3, and the plant-level water use efficiency (WUE ) was also higher in IL 11-3 and in M82 for WD plants. The ratio of trichomes to stomata (T/S) was positively correlated with WUE and WUE , indicating an important role for both trichomes and stomata in drought tolerance in tomato, and offering a promising way to select for improved water use efficiency of major crops.

TheLanatatrichome mutation increases stomatal conductance and reduces leaf temperature in tomato

“…This basal rate of water loss is expressed as the minimum conductance of a leaf ( g min ). Both g min and stomatal closure can be affected by trichomes (Hegebarth et al , 2016; Galdon-Armero et al , 2018). However, we found no differences in g min among the genotypes evaluated in this experiment (Supplementary data Fig.…”

“…Given the relationship between trichomes and water relations, recent research has evaluated the role of trichomes in tolerance and adaptation to water stress (Sletvold, 2011; Ewas et al , 2016; Mo et al , 2016; Galdon-Armero et al , 2018). In Arabidopsis lyrata , plants with higher density of trichomes were more tolerant to drought than glabrous plants (Sletvold, 2011).…”

“…In tomato, overexpression of MIXTA-like MYB transcription factor led to higher density of trichomes and tolerance to water stress (Ewas et al , 2016). Further work demonstrated that the ratio of trichomes to stomata plays a role in avoiding excessive water loss (Galdon-armero et al , 2018). Collectively, these results make increasing glandular trichome density in crops an appealing breeding prospect, for instance glandular trichome type IV, which is found in wild tomato relatives but not in adult leaves of cultivated tomato (Vendemiatti et al , 2017).…”

Phenotyping in Arabidopsis and Crops—Are We Addressing the Same Traits? A Case Study in Tomato

“…Stomata can subsequently be counted and measured under an optical or confocal microscope. For more sophisticated analyses, variable pressure scanning electron microscopes are used to address stomata features [29]. Using this method, a fixation of leaf material is not necessary and damage through fixation can be avoided.…”

“…The analysis of trichomes in drought studies is common, as these specialized epidermal cells manipulate the microclimate of the thin air layer surrounding the leaf, and can thereby, prevent unproductive water losses. Enhanced trichome density in drought tolerant genotypes is found in tomato [29] and Arabidopsis [114], and can be assessed via light microscopy or scanning electron microscopy.…”