Silicon affects seed development and leaf macrohair formation in Brachypodium distachyon

Abstract

Silicon (Si) has many beneficial effects in plants, especially for the survival from biotic and abiotic stresses. However, Si may negatively affect the quality of lignocellulosic biomass for bioenergy purposes. Despite many studies, the regulation of Si distribution and deposition in plants remains to be fully understood. Here, we have identified the Brachypodium distachyon mutant low-silicon 1 (Bdlsi1-1), with impaired channeling function of the Si influx transporter BdLSI1, resulting in a substantial reduction of Si in shoots. Bioimaging by laser ablation-inductively coupled plasma-mass spectrometry showed that the wild-type plants deposited Si mainly in the bracts, awns and leaf macrohairs. The Bdlsi1-1 mutants showed substantial (>90%) reduction of Si in the mature shoots. The Bdlsi1-1 leaves had fewer, shorter macrohairs, but the overall pattern of Si distribution in bracts and leaf tissues was similar to that in the wild-type. The Bdlsi1-1 plants supplied with Si had significantly lower seed weights, compared to the wild-type. In low-Si media, the seed weight of wild-type plants was similar to that of Bdlsi1-1 mutants supplied with Si, while the Bdlsi1-1 seed weight decreased further. We conclude that Si deficiency results in widespread alterations in leaf surface morphology and seed formation in Brachypodium, showing the importance of Si for successful development in grasses.

The impact of silicon on cell wall composition and enzymatic saccharification of Brachypodium distachyon

“…The low - silicon 1 mutant ( Bdlsi1 - 1 ) plants used in this study carry a mutation in the Si influx transporter (BdLSI1), localized in the roots. The mutation severely hinders Si uptake and resulted in 93% reduction of the shoot Si content [ 29 ]. No phenotypic consequences were observed as the morphology and development of the Bdlsi1 - 1 plants were similar to the wild-type plants [ 29 ].…”

“…In addition, the Si uptake system and the levels of Si accumulation in shoot tissues are similar to those in barley, maize and wheat. Together these properties make B. distachyon a valuable tool for studies of biomass conversion [ 28 , 29 ].…”

Elevated atmospheric CO2 suppresses jasmonate and silicon‐based defences without affecting herbivores

“…In addition, Si supplementation has been shown to reduce the digestive efficiency through reduced cell rupture during insect digestion (Hunt et al, 2008). Previous work has found that Si is primarily deposited in leaf macrohairs in B. distachyon and that Si supplementation significantly increases both the number and length of these macrohairs (Głazowska, Murozuka, Persson, Castro, & Schjoerring, 2018). Our results indicate that this is an effective mechanical defence strategy against chewing herbivory in B. distachyon .…”

Grass secondary cell walls, Brachypodium distachyon as a model for discovery

“…However, silicon may interact with polysaccharides, which consequently affect plant biomass processing in biorefineries (Perry & Lu, 1992;Kido et al, 2015). For biofuel production, there is a trade-off between soil amendment with silicon that can increase polysaccharide yield with a negative effect on the conversion of biomass into biofuels (Głazowska et al, 2018b). Silicon content in rice and maize can be modulated by changing the expression of silicon transporters (Ma et al, 2007;Mitani-Ueno et al, 2016;Bokor et al, 2017).…”

“…Silicon content in rice and maize can be modulated by changing the expression of silicon transporters (Ma et al, 2007;Mitani-Ueno et al, 2016;Bokor et al, 2017). The analysis of different silicon transporter mutants showed that silicon availability may impact the morphology and patterning of stem and leaf macrohairs (Głazowska et al, 2018b). The Bd low silicon 1 (Bdlsi1) mutant is impaired in silicon transporter function and has reduced silicon uptake, with 93% less silicon present in the shoot.…”