Dysfunction of the 4-coumarate:coenzyme A ligase 4CL4 impacts aluminum resistance and lignin accumulation in rice
Dysfunction of the 4-coumarate:coenzyme A ligase 4CL4 impacts aluminum resistance and lignin accumulation in rice
复制标题
4-香豆酸：辅酶 A 连接酶 4CL4 的功能障碍影响水稻的铝抗性和木质素积累
DOI：
10.1111/tpj.14995
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发表时间：
2020-10-16
期刊：
影响因子：
7.2
通讯作者：
Huang, Chao-Feng
中科院分区：
文献类型：
--
作者：
Liu, Shuo;Zhao, Li;Huang, Chao-Feng
根细胞壁是铝(Al)毒害的首要靶点。单子叶植物，如水稻，可以积累大量的羟基肉桂酸(HCAs)来修饰和交联细胞壁的半纤维素和/或木质素。然而，目前尚不清楚这种由HCA介导的细胞壁修饰是否对铝的积累和抗性具有重要作用。我们先前分离并鉴定了一个riceral1(对铝的抗性1)突变体，该突变体表现出增强的铝抗性。在这项研究中，我们克隆了RAL1，发现它编码4-香豆酸：辅酶A连接酶4CL4，一个可能参与木质素生物合成的酶。RAL1/4CL4突变降低了木质素含量，增加了其底物4-香豆酸(PA)和阿魏酸(FA)的积累。我们证明，在ral1/4cl4突变体中，木质素积累的改变不是增强铝抗性所必需的。我们发现，PA和FA的积累增加可以减少铝与半纤维素的结合，从而增强ral1/4Cl4突变体的抗铝性。铝胁迫能够触发PA和FA的积累，这可能是通过抑制RAL1/4CL4及其同源基因的表达而引起的。因此，我们的结果表明，铝诱导的PA和FA的积累是通过改变细胞壁从而减少与细胞壁的铝结合而积极和积极地参与水稻对铝的抗性。
The root cell wall is the first and primary target of aluminum (Al) toxicity. Monocots such as rice (Oryza sativa) can accumulate appreciable levels of hydroxycinnamic acids (HCAs) to modify and cross-link hemicellulose and/or lignin of the cell wall. Nevertheless, it is unclear whether this HCA-mediated modification of the cell wall is important for Al accumulation and resistance. We previously isolated and characterized a riceral1(resistance toaluminum1) mutant that shows enhanced Al resistance. In this study, we clonedRAL1and found that it encodes the 4-coumarate:coenzyme A ligase 4CL4, an enzyme putatively involved in lignin biosynthesis. Mutation ofRAL1/4CL4reduces lignin content and increases the accumulation of its substrates 4-coumaric acid (PA) and ferulic acid (FA). We demonstrate that altered lignin accumulation is not required for the enhanced Al resistance inral1/4cl4mutants. We found that the increased accumulation of PA and FA can reduce Al binding to hemicellulose and consequently enhance Al resistance inral1/4cl4mutants. Al stress is able to trigger PA and FA accumulation, which is likely caused by the repression of the expression ofRAL1/4CL4and its homologous genes. Our results thus reveal that Al-induced PA and FA accumulation is actively and positively involved in Al resistance in rice through the modification of the cell wall and thereby the reduced Al binding to the cell wall.