A mechanistic view on lodging resistance in rye and wheat: a multiscale comparative study

Abstract

Summary The development of crop varieties that are resistant to lodging is a top priority for breeding programmes. Herein, we characterize the rye mutant ´Stabilstroh’ (‘stable straw’) possessing an exceptional combination of high lodging resistance, tall posture and high biomass production. Nuclear magnetic resonance imaging displayed the 3‐dimensional assembly of vascular bundles in stem. A higher number of vascular bundles and a higher degree of their incline were the features of lodging‐resistant versus lodging‐prone lines. Histology and electron microscopy revealed that stems are fortified by a higher proportion of sclerenchyma and thickened cell walls, as well as some epidermal invaginations. Biochemical analysis using Fourier‐transform infrared spectroscopy and inductively coupled plasma‐optical emission spectrometry further identified elevated levels of lignin, xylan, zinc and silicon as features associated with high lodging resistance. Combined effects of above features caused superior culm stability. A simplistic mathematical model showed how mechanical forces distribute within the stem under stress. Main traits of the lodging‐resistant parental line were heritable and could be traced back to the genetic structure of the mutant. Evaluation of lodging‐resistant wheat ‘Babax’ (‘Baviacora’) versus contrasting, lodging‐prone, genotype ´Pastor´ agreed with above findings on rye. Our findings on mechanical stability and extraordinary culm properties may be important for breeders for the improvement of lodging resistance of tall posture cereal crops.

Seeing plants as never before

“…High yielding cereal varieties need to develop stems with a high degree of mechanical strength to avoid wind‐induced collapse (referred to as ‘lodging’). MRI‐based investigation of the structure of both the wheat and the rye stem has shown that lodging resistance is associated with both a high number of vascular bundles and a greater degree of their incline (Muszynska et al ., 2021).…”

The dynamics of touch‐responsive gene expression in cereals

“…Quantitative and histochemical analysis further indicated that wounding increased lignin accumulation and activity of enzymes involved in lignin synthesis, which resulted in increased mechanical strength and the lodging resistance index in the main stem. Varieties with higher lodging resistance have elevated levels of lignin, xylan, zinc, and silicon (Muszynska et al., 2021). Somewhat surprisingly, genes associated with lignin biosynthesis were generally downregulated in the later time points of our 2‐h time course, while lignin content has been reported to be increased after mechanostimulation in, e.g., Brachypodium, Arabidopsis, and Papaya (Brenya et al., 2020; Gladala‐Kostarz et al., 2020; Porter et al., 2009).…”

Biomolecular Strategies for Vascular Bundle Development to Improve Crop Yield

“…The number of vascular bundles is one of the important factors affecting the mechanical properties of stems [ 89 , 90 ]. Muszynska et al [ 91 ] compared extreme lodging rye mutants and found that the lodging-resistant rye strain “MS135” was taller, with more tiller, had higher biomass production and heavier stalks with significantly more outer vascular bundles, and had a higher proportion of sclerenchyma cells. Recent research has shown that vascular bundles and surrounding leaf sheaths also contribute significantly to lodging resistance [ 92 , 93 , 94 , 95 ].…”