Raman developmental markers in root cell walls are associated with lodging tendency in tef

Abstract

Main conclusion Using Raman micro-spectroscopy on tef roots, we could monitor cell wall maturation in lines with varied genetic lodging tendency. We describe the developing cell wall composition in root endodermis and cylinder tissue. Abstract Tef [Eragrostis tef (Zucc.) Trotter] is an important staple crop in Ethiopia and Eritrea, producing gluten-free and protein-rich grains. However, this crop is not adapted to modern farming practices due to high lodging susceptibility, which prevents the application of mechanical harvest. Lodging describes the displacement of roots (root lodging) or fracture of culms (stem lodging), forcing plants to bend or fall from their vertical position, causing significant yield losses. In this study, we aimed to understand the microstructural properties of crown roots, underlining tef tolerance/susceptibility to lodging. We analyzed plants at 5 and 10 weeks after emergence and compared trellised to lodged plants. Root cross sections from different tef genotypes were characterized by scanning electron microscopy, micro-computed tomography, and Raman micro-spectroscopy. Lodging susceptible genotypes exhibited early tissue maturation, including developed aerenchyma, intensive lignification, and lignin with high levels of crosslinks. A comparison between trellised and lodged plants suggested that lodging itself does not affect the histology of root tissue. Furthermore, cell wall composition along plant maturation was typical to each of the tested genotypes independently of trellising. Our results suggest that it is possible to select lines that exhibit slow maturation of crown roots. Such lines are predicted to show reduction in lodging and facilitate mechanical harvest.

Deposition of silica in sorghum root endodermis modifies the chemistry of associated lignin

“…The periphery of the aggregates, characterized by negative PC1 values, indicated high abundance of lignin bands at 1605 and 1633 cm -1 . These bands are typical to lignin with low levels of polymerization ( Diehn et al., 2024 ). Locations farther from the aggregate were represented by negative PC2 values, with bands typical to polysaccharides and acetylated pectin at 818, 861, and 1453 cm -1 ( Synytsya et al., 2003 ; Xiao et al., 2020 ).…”

“…The main band in PC2 and PC3 was assigned to lignin radicals at 1572-1594 cm -1 ( Barsberg et al., 2006 ). Negative loadings of PC2 at 1600 and 1614 cm –1 could represent highly polymerized lignin in the spot center while positive bands at 1603 and 1628 cm -1 possibly represent less mature lignin with a lower degree of polymerization in the background ITCW ( Diehn et al., 2024 ). The positive values of PC3 surrounding the center of the spot represented polysaccharides at 1092, 1165, 1313, and 1378 cm -1 ( Agarwal and Ralph, 1997 ).…”