Soybean Mutants Lacking Abundant Seed Storage Proteins Are Impaired in Mobilization of Storage Reserves and Germination

Abstract

Spontaneous and radiation-induced mutants of soybean, despite loss of abundant seed proteins, have been reported to grow and reproduce normally without any apparent physiological abnormalities. Here, we report the development and characterization of a soybean line (BSH-2) that lacks several abundant seed storage proteins. One-dimensional and high-resolution two-dimensional gel electrophoresis revealed the absence of the α′ and α subunits of β-conglycinin and G1, G2, G4, and G5 glycinin in the newly developed mutant line (BSH-2). Like our earlier developed soybean mutant line (BSH-3), the seeds of BSH-2 also accumulated high levels of free amino acids as compared with wild-type DN47 seeds. An examination of the germination rates revealed that both BSH-2 and BSH-3 had significantly lower germination rates compared with the parent line DN47. Two-dimensional gel electrophoresis analysis demonstrated that these mutants had slower rates of mobilization of seed storage proteins. The delayed mobilization of storage proteins in BSH-2 and BSH-3 seeds was also correlated with a delayed induction of proteolytic activity in the mutants when compared to DN47. Similarly, qRT-PCR analysis revealed distinct expression pattern of genes involved in proteolytic pathway in the mutants when compared to DN47. Transmission electron microscopy observation of soybean seeds at two germination stages revealed striking differences in the breakdown of protein storage vacuoles and lipid bodies in the mutants. Our study demonstrates that BSH-2 and BSH-3 are compromised in mobilization of storage reserves and the absence of abundant storage proteins may affect the seed germination efficiency and post-germinative seedling establishment.

Protein quality parameters and storage protein profiling of mungbean interspecific lines (Vigna radiata L. Wilczek)

“…Storage proteins serve as a source of nitrogen, carbon and sulfur and are thus essential for plant's growth, development and providing resistance against pests, pathogens and desiccation. Absence or low content of storage proteins may affect the seed germination efficiency and post-germinative seedling establishment (WEI et al, 2020). Thus, having a knowledge about protein fractions could help in genetic engineering and breeding programs to improve storage protein quality and quantity in mungbean seeds.…”

The genomic and transcriptomic foundations of viviparous seed development in mangroves

“…Moreover, they were specifically and highly expressed in the reproductive organs of C. brachiata. Among many other functions, seed storage proteins (orthogroup OG0001910) serve as sources of carbon and nitrogen for seed germination (Wei et al 2020). Oleosin family proteins (orthogroups: OG0002151 and OG0007120) are another nutrient in seeds (Lu et al 2018) while seed maturation proteins (orthogroup: OG0014483 and OG0015329) are involved in secondary dormancy (Kushwaha et al 2012).…”

“…Adequate nutrients stored in seeds are essential for germination. To this end, seed storage proteins, maturation proteins and late embryogenesis abundant proteins are massively accumulated during seed development, especially at the late stage of maturation and act as the main source of nitrogen, carbon, and sulfur at germination (Wei et al 2020). However, lack of nutrient storage in vivipary mangrove embryos could influence the development of seeds, promoting germination using nutrients from maternal tissues.…”

Unfolding the Dynamics of Mineral Nutrients and Major Storage Protein Fractions during Soybean Seed Development

“…3,4 Notably, ca. 70% of the soybean seeds' proteome regards storage proteins, 5,6 which serves as an N source during seed germination and early-seedling development and are stowed in the protein bodies, a specialized group of vesicles located at seed cotyledon's cells. 7,8 These proteins are mainly constituted of water-soluble albumins and salt-soluble globulin fractions.…”

“…This later is divided into legumins and the vicilins families, which are, in turn, composed of glycinin and β-conglycinin proteins, respectively. 6,7,9 Nevertheless, despite its importance either as a food or feed source, soybean seed's storage proteins are remarkably deficient in sulfur amino acids, i.e., methionine and cysteine, 7,10 essential for animals, including humans, 11,12 which has been associated with the relative abundance of βconglycinin's β-peptide. 13,14 In this scenario, significant efforts aimed at boosting the concentration and quality of the storage proteins have been made.…”