College of Agronomy, Hunan Agricultural University, Changsha 410128, China.
State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China.
J Exp Bot. 2024 Jan 1;75(1):123-136. doi: 10.1093/jxb/erad367.
Lignin and cellulose are two essential elements of plant secondary cell walls that shape the mechanical characteristics of the culm to prevent lodging. However, how the regulation of the lignin and cellulose composition is combined to achieve optimal mechanical characteristics is unclear. Here, we show that increasing OsTCP19 expression in rice coordinately repressed lignin biosynthesis and promoted cellulose biosynthesis, resulting in enhanced lodging resistance. In contrast, repression of OsTCP19 coordinately promoted lignin biosynthesis and inhibited cellulose biosynthesis, leading to greater susceptibility to lodging. We found that OsTCP19 binds to the promoters of both MYB108 and MYB103L to increase their expression, with the former being responsible for repressing lignin biosynthesis and the latter for promoting cellulose biosynthesis. Moreover, up-regulation of OsTCP19 in fibers improved grain yield and lodging resistance. Thus, our results identify the OsTCP19-OsMYB108/OsMYB103L module as a key regulator of lignin and cellulose production in rice, and open up the possibility for precisely manipulating lignin-cellulose composition to improve culm mechanical properties for lodging resistance.
木质素和纤维素是植物次生细胞壁的两个重要组成部分，它们决定了茎秆的机械特性，以防止倒伏。然而，木质素和纤维素组成的调节如何结合以达到最佳的机械特性尚不清楚。在这里，我们表明，增加水稻中 OsTCP19 的表达协同抑制木质素生物合成并促进纤维素生物合成，从而增强抗倒伏性。相比之下，OsTCP19 的抑制协同促进木质素生物合成并抑制纤维素生物合成，导致对倒伏的敏感性增加。我们发现 OsTCP19 结合到 MYB108 和 MYB103L 的启动子上以增加它们的表达，前者负责抑制木质素生物合成，后者负责促进纤维素生物合成。此外，纤维中 OsTCP19 的上调提高了产量和抗倒伏性。因此，我们的结果确定了 OsTCP19-OsMYB108/OsMYB103L 模块作为水稻中木质素和纤维素产生的关键调节剂，并为精确操纵木质素-纤维素组成以改善茎秆机械性能以提高抗倒伏性开辟了可能性。
