Accumulation of proanthocyanidins and/or lignin deposition in buff-pigmented soybean seed coats may lead to frequent defective cracking

Abstract

Defective cracking frequently occurs in buff-pigmented soybean seed coats, where proanthocyanidins accumulate and lignin is deposited, suggesting that proanthocyanidins and/or lignin may change physical properties and lead to defective cracking. In the seed production of many yellow soybean (Glycine max) cultivars, very low percentages of self-pigmented seeds are commonly found. This phenomenon is derived from a recessive mutation of the I gene inhibiting seed coat pigmentation. In Japan, most of these self-pigmented seeds are buff-colored, and frequently show multiple defective cracks in the seed coat. However, it is not known why cracking occurs specifically in buff seed coats. In this study, quantitative analysis was performed between yellow and buff soybean seed coats. Compared with yellow soybeans, in which defective cracking rarely occurs, contents of proanthocyanidins (PAs) and lignin were significantly higher in buff seed coats. Histochemical data of PAs and lignin in the seed coats strongly supported this result. Measurements of the physical properties of seed coats using a texture analyzer showed that a hardness value was significantly decreased in the buff seed coats. These results suggest that PA accumulation and/or lignin deposition may affect the physical properties of buff seed coats and lead to the defective cracking. This work contributes to understanding of the mechanism of defective cracking, which decreases the seed quality of soybean and related legumes.

A QTL associated with high seed coat cracking rate of a leading Japanese soybean variety

“…Despite this, few analytical progresses have been reported. Senda et al (2017) suggested that proanthocyanidins and lignin are related to the SCC of buff-pigmented soybean seeds. Percy et al (1999) reported that soluble proline-rich cell wall protein is absent in net-like seed-coat-defective soybean lines.…”

Metabolite Fingerprinting of Kersting's Groundnut [Macrotyloma geocarpum (Harms) Maréchal & Baudet] Seeds Using UPLC-qTOF-MS Reveals the Nutraceutical and Antioxidant Potentials of the Orphan Legume

“…Since procyanidins B are mostly catechin dimers, these compounds, previously identified in the seed and seed coats of lentil, pardina lentil, pea and common bean were assigned as procyanidin B1 and procyanidin B2 because of the MS 2 fragment ion [M-H] − at m/z 289 which is characteristic of catechin monomer (49). The presence of procyanidin type B dimers has been described in seeds of most grain legumes, and their synthesis may depend on the legume's phenotype (50,51). Moreover, B-type procyanidin trimers which were found in the test landraces were earlier detected in the seeds of cowpea, adzuki bean, pea and lentil (4,49).…”

Weathering deterioration in pre-harvest of soybean seeds: physiological, physical, and morpho-anatomical changes

“…Anatomical characterization showed the rupture and compression of the hourglass cells (second cell layer of the seed coat) that act to softening the effects of expansion, contraction, and rupture of the parenchyma cells when subjected to subsequent hydration and dehydration cycles (Forti et al, 2013;Senda et al, 2017). Therefore, cotyledonary cells of the seeds under simulated precipitation were more exposed to environmental conditions, and their deterioration process increased, which was reinforced by the results of the physiological and X-ray tests.…”