Gene expression in the lignin biosynthesis pathway during soybean seed development

Abstract

ABSTRACT. The study of gene expression in plants is fundamental, and understanding the molecular mechanisms involved in important biological processes, such as biochemical pathways or signaling that are used or manipulated in improvement programs, are key for the production of highquality soybean seeds. Reports related to gene expression of lignin in seeds are scarce in the literature. We studied the expression of the phenylalanine ammonia-lyase (PAL), cinnamate 4-hydroxylase, 4-hydroxycinnamate 3-hydroxylase, and cinnamyl alcohol dehydrogenase genes involved in lignin biosynthesis during the development of soybean (Glycine max L. Merrill) seeds. As the endogenous control, the eukaryotic elongation factor 1-beta gene was used in two biological replicates performed in triplicate. Relative quantitative expression of these genes during the R4, R5, R6, and R7 development stages was analyzed. Real-time polymerase chain reaction was used for the gene expression study. The analyses were carried out in an ABI PRISM 7500 thermocycler using the comparative Ct method and SYBR Green to detect amplification. The seed samples at the R4 stage were chosen as calibrators. Increased expression of the cinnamate-4-hydroxylase and PAL genes occurred in soybean seeds at the R5 and R6 development stages. The cinnamyl alcohol dehydrogenase gene was expressed during the ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 12 (3): 2618-2624 (2013 Gene expression of lignin biosynthesis in soybean seeds 2619 final development phases of soybean seeds. In low-lignin soybean cultivars, the higher expression of the PAL gene occurs at development stages R6 and R7. Activation of the genes involved in the lignin biosynthesis pathway occurs at the beginning of soybean seed development.

A Mechanistic Study on the Toxic Effect of Copper Oxide Nanoparticles in Soybean (Glycine max L.) Root Development and Lignification of Root Cells

“…However, the expression levels of POD genes were significantly high at higher concentrations of CuONPs exposure. Baldoni et al [31] have reported that significant increase in the expression levels of PAL, C4H, and CAD genes occurred during seed development in soybean. They observed that the expression of PAL and C4H genes was high at early stages of lignin biosynthesis during seed development.…”

“…Therefore, the increased expression levels of PAL, C4H, and CAD genes strengthens the hypothesis that exposure to CuONPs induces the lignification process in soybean. Moreover, based on the results obtained from previous studies on the expression of PAL, C4H, and CAD genes [31,32], it could be assumed that the reason for the higher expression levels of these genes under lower concentrations of CuONPs exposure might be due to the less toxicity at lower concentrations of CuONPs exposure leading to the slower lignin biosynthesis.…”

Seed Nutrition and Quality, Seed Coat Boron and Lignin Are Influenced by Delayed Harvest in Exotically-Derived Soybean Breeding Lines under High Heat

“…The role of seed coat lignin (lig) for seed composition, germination, vigor, and seed and seed coat physical and chemical properties was previously reported by Pereira et al ( 1985 ), Alvarez et al ( 1997 ), Romkaew et al ( 2008 ), Bellaloui et al ( 2012b ), Baldoni et al ( 2013 ), and de Oliveira et al ( 2014 ). However, in these studies, there were no lines with HG.…”

“…This indicates that HG lines maintained higher levels of sugars under stress environments (weathering effects), which may be due to less leakage of these sugars through the seed coat and seed membrane as a result of the higher content of SCB and Lig. Both Lig and SCB were reported to be involved in carbohydrate and phenolic metabolism (Marschner, 1995 ) to protect cell walls and cell membranes from the physical damage of seed coat deterioration (Pereira et al, 1985 ; Alvarez et al, 1997 ; Romkaew et al, 2008 ; Bellaloui et al, 2012b ; Baldoni et al, 2013 ; de Oliveira et al, 2014 ), especially under stress environments. The biological functions of the oligosaccharides are not clear (Ren et al, 2009 ), but other researchers, for example, Obendorf ( 1997 ) reported that oligosaccharides and sucrose are important for desiccation tolerance during soybean seed development and maturation, and protection of seeds against damage during seed dehydration and aging.…”

“…Soybean is an important crop in the world and is mainly produced in the USA (36.7%), Brazil (31%), Argentina (16%), and China (4.8%) (Belewu and Belewu, 2007 ; FAOSTAT, 2011 ). Seed of soybean is a source of soymeal for livestock, and oil for human consumption (Wilson, 2004 ), and recently, for biodiesel production (Baldoni et al, 2013 ; Santos et al, 2013 ). Soybean seed contain about 37–45% protein, 19 to 25% triglyceride oil composed of various fatty acids (palmitic: 9–14%; stearic: 2–5%; oleic: 19–28%; linoleic: 48–58%; and linolenic 5–11%) (Wilson, 2004 ; Bellaloui et al, 2017 ).…”