Rivai Reza Ramdan, Yamazaki Kiyoshi, Kobayashi Masaru, Tobimatsu Yuki, Tokunaga Tsuyoshi, Fujiwara Toru, Umezawa Toshiaki
Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan.
Research Center for Applied Botany, National Research and Innovation Agency of the Republic of Indonesia, Bogor 16911, Indonesia.
Plant Cell Physiol. 2024 Dec 21;65(12):1983-1992. doi: 10.1093/pcp/pcae114.
Sorghum [Sorghum bicolor (L.) Moench] has been receiving attention as a feedstock for lignocellulose biomass energy. During the combustion process, ash-containing silicon (Si) can be produced, which causes problems in furnace maintenance. Hence, lowering Si content in plants is crucial. However, limiting Si supply to crops is difficult in practice because Si is abundant in the soil. Previously, an Si uptake transporter (SbLsi1) has been identified, and an Si-depleted mutant has also been generated in the model sorghum variety BTx623. In this study, we aimed to investigate the changes induced by a mutation in SbLsi1 on the accumulation and structure of lignin in cell walls. Through chemical and NMR analyses, we demonstrated that the lsi1 mutation resulted in a significant increase in lignin accumulation levels as well as a significant reduction in Si content. At least some of the modification was induced by transcriptional changes, as suggested by the upregulation of phenylpropanoid biosynthesis-related genes in the mutant plants. These findings derived from the model variety could be useful for the future development of practical cultivars with high biomass and less Si content for bioenergy applications.
高粱[Sorghum bicolor (L.) Moench]作为木质纤维素生物质能源的原料受到了关注。在燃烧过程中，可能会产生含硅（Si）的灰分，这会给炉膛维护带来问题。因此，降低植物中的硅含量至关重要。然而，在实践中限制作物对硅的供应很困难，因为土壤中硅含量丰富。此前，已鉴定出一种硅吸收转运体（SbLsi1），并且在模式高粱品种BTx623中也产生了一个硅缺乏突变体。在本研究中，我们旨在研究SbLsi1突变对细胞壁中木质素积累和结构的影响。通过化学和核磁共振分析，我们证明lsi1突变导致木质素积累水平显著增加，同时硅含量显著降低。如突变体植株中苯丙烷生物合成相关基因的上调所表明的，至少部分修饰是由转录变化诱导的。这些来自模式品种的发现可能有助于未来开发具有高生物量和低硅含量的实用品种用于生物能源应用。
