Nitrogen deficiency results in changes to cell wall composition of sorghum seedlings

Abstract

Sorghum [Sorghum bicolor (L.) Moench] has been gaining attention as a feedstock for biomass energy production. While it is obvious that nitrogen (N) supply significantly affects sorghum growth and biomass accumulation, our knowledge is still limited regarding the effect of N on the biomass quality of sorghum, such as the contents and structures of lignin and other cell wall components. Therefore, in this study, we investigated the effects of N supply on the structure and composition of sorghum cell walls. The cell walls of hydroponically cultured sorghum seedlings grown under sufficient or deficient N conditions were analyzed using chemical, two-dimensional nuclear magnetic resonance, gene expression, and immunohistochemical methods. We found that the level of N supply considerably affected the cell wall structure and composition of sorghum seedlings. Limitation of N led to a decrease in the syringyl/guaiacyl lignin unit ratio and an increase in the amount and alteration of tissue distribution of several hemicelluloses, including mixed linkage (1 → 3), (1 → 4)-β-d-glucan, and arabinoxylan. At least some of these cell wall alterations could be associated with changes in gene expression. Nitrogen status is thus one of the factors affecting the cell wall properties of sorghum seedlings.

Nitrogen and phosphorus deficiencies alter primary and secondary metabolites of soybean roots

“…Our transcriptome data shows that in LN condition, soybean roots increase expression of genes for secondary wall formation and cell wall loosening, but in LNP, no distinct behaviour can be discerned except cell wall loosening and inhibition of secondary cell wall formation. The effects of N availability on secondary cell wall formation and its components have been reported for different plants, including rice (W. , maize (Sun et al, 2018), poplar (Pitre et al, 2007), sorghum (Rivai et al, 2021), and Eucalyptus (Camargo et al, 2014), but the effects are different in different plant species. In Eucalyptus, N deprivation led to increase in lignin in secondary cell wall, but in sorghum, it caused accumulation of several hemicelluloses.…”

“…The effects of N availability on secondary cell wall formation and its components have been reported for different plants, including rice (W. Zhang et al, 2017), maize (Sun et al, 2018), poplar (Pitre et al, 2007), sorghum (Rivai et al, 2021), and Eucalyptus (Camargo et al, 2014), but the effects are different in different plant species. In Eucalyptus, N deprivation led to increase in lignin in secondary cell wall, but in sorghum, it caused accumulation of several hemicelluloses.…”

“…In Eucalyptus, N deprivation led to increase in lignin in secondary cell wall, but in sorghum, it caused accumulation of several hemicelluloses. One reason for the alteration of cell wall in N deficiency could be an adaptation strategy to limitation of N-containing molecules, such as proteins and amono acids and reduction in demand for carbon skeletons for N assimilation, so, plants may accumulate surplus carbon as starch or utilize it for cell wall materials (Rivai et al, 2021). This is consistent with the reduction in expressions of genes for nitrogen metabolism, such as GDH and GOGAT in our results.…”

Receptor kinase LecRK-I.9 regulates cell wall remodelling and signalling during lateral root formation inArabidopsis

“…A lower nitrate concentration in the culture medium (KNO 3 0.1 mM) was also tested. Even if nitrogen has a small effect on LR number and density (Forde, 2014), it is a major element affecting CW composition and dynamics (Fernandes et al ., 2016a; Qin et al ., 2019; Rivai et al ., 2021). When grown at 0.1 mM KNO 3 , lecrk-I.9 and dominant negative mutants exhibited twice more LRs than WT, over-expressors and complemented plants (Fig.…”

“…In A. thaliana , nitrate exerts its effect on LR length rather than on LR number or density (Forde, 2014). However, nitrate deficiency strongly affects both the polysaccharide composition and the enzymatic repertoire of the CW (Fernandes et al ., 2016a; Fernandes et al ., 2016b; Qin et al ., 2019; Rivai et al ., 2021). All these studies showed a decrease in cellulose content which correlated with an increase in hemicellulose and/or pectin contents.…”