GmFNSII-Controlled Soybean Flavone Metabolism Responds to Abiotic Stresses and Regulates Plant Salt Tolerance

Abstract

Flavones, a major group of flavonoids in most plant tissues, play multiple roles in plant-environment interactions. In our study, the expression of the two soybean flavone synthase genes, GmFNSII-1 and GmFNSII-2, was significantly increased by methyl jasmonate (MeJA), glucose, mannitol and NaCl treatment, which were also found to increase flavone aglycone accumulation in Glycine max (L.) Merrill. In the GmFNSII-1 promoter, a specific CGTCA motif in the region (-979 bp to -806 bp) involved in the MeJA response was identified. Promoter deletion analysis of GmFNSII-2 revealed the presence of osmotic-responsive (-1,143 bp to -767 bp) and glucose-repressive sequence elements (-767 bp to -475 bp), which strongly supported the hypothesis that glucose induces soybean flavone production by acting as both an osmotic factor and a sugar signaling molecule simultaneously. Silencing of the GmFNSII gene clearly reduced the production of flavone aglycones (apigenin, luteolin and 7,4'-dihydroxyflavone) in hairy roots. The GmFNSII-RNAi (RNA interference) roots that had a reduced level of flavones accompanied by more malondialdehyde and H2O2 accumulation were more sensitive to salt stress compared with those of the control, and we concluded that flavones, as antioxidants, are associated with salt tolerance.

The soybean R2R3 MYB transcription factor GmMYB100 negatively regulates plant flavonoid biosynthesis

“…Soybean (cultivar 'Hefeng 47') seedlings grew under the condition as described (Yan et al 2014). In gene expression experiments, V1 stage soybean seedlings were pulled out and removed excess vermiculite, then transferred to either sterile 1/4 strength Murashige and Skoog (MS) solution containing appropriate concentrations of methyl jasmonate (MeJA, 100 lM), salicylic acid (SA, 0.5 M), and sucrose (0.4 M), or the Bradyrhizobium japonicum (USDA110, OD 600 = 0.08) in nitrogen-free plant nutrient solution (N-PNS) for different treatments.…”

“…The gene expression was detected by real-time PCR as described previously (Yan et al 2014). Three soybean genes (ACTIN, ELF1B, and CYB2) were used as reference genes to calculate the relative mRNA levels.…”

“…Flavone aglycone analysis in soybean hairy roots was performed as described previously (Yan et al 2014). The total flavonol content in Arabidopsis seedlings was measured according to the aluminum chloride colorimetric method (Chang et al 2002).…”

“…Flavonoids are implicated in a variety of biological processes, such as flower coloring and pollination (Lepiniec et al 2006), sexual reproduction (Mol et al 1998), UV protection (Li et al 1993;Harborne and Williams 2000), alleviation of oxidative damage (Albert et al 2009;Yan et al 2014), defense against pathogens and insects (Dixon et al 2005), and root endosymbiosis (Subramanian et al 2006;Abdel-Lateif et al 2012;Hassan and Mathesius 2012). In human body, flavonoids, derived from food sources such as vegetables, fruits, tea and red wine, can induce apoptosis, stimulate DNA repair, scavenge free radicals, protect damage from oxidative stress, and inhibit the division of cancer cells (Khan et al 2010).…”

Mechanisms of Soybean Roots' Tolerances to Salinity Revealed by Proteomic and Phosphoproteomic Comparisons Between Two Cultivars

“…Plants have evolved a series of adaptive mechanisms to sense and respond to salinity cues and these include active involvements of multiple phosphorylation cascades, such as salt overly sensitive (SOS) pathway, phosphatidic acid (PA)-mediated activation of calcium-dependent protein kinase (CDPK), abscisic acid (ABA)-regulated activation of mitogen-activated protein kinase (MAPK) cascades (11)(12)(13)(14). Phosphorylation of specific signaling components are known to be initiated at critical time points after plants been subjected to the salt stresses (15) and they coordinate specific metabolic processes, cell-wall porosity and lateral root initiation to help plants adapt to salt stresses (10,13,16). Recently, major high throughput strategies including transcriptomic, proteomic, and metabolomic approaches, have been used to dissect the responses of soybean root to salinity stress (17)(18)(19)(20)(21).…”