Salicylic acid mediates the reduced growth of lignin down-regulated plants
Salicylic acid mediates the reduced growth of lignin down-regulated plants
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DOI：
10.1073/pnas.1117873108
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发表时间：
2011-12-20
影响因子：
11.1
通讯作者：
Dixon, Richard A.
中科院分区：
文献类型：
--
作者：
Gallego-Giraldo, Lina;Escamilla-Trevino, Luis;Dixon, Richard A.
在拟南芥和紫花苜蓿中，羟基肉桂酰辅酶A：莽草酸羟基肉桂酰基转移酶(HCT)的下调导致木质素水平显著降低，细胞壁对糖释放的抵抗力降低，但植株严重矮化。在一系列木质素生物合成受到干扰的转基因紫花苜蓿植株中，胁迫激素水杨酸(SA)的水平与木质素水平和生长成反比。通过从基因上阻止SA的形成或导致其移除来降低SA水平，可以恢复Hct下调调控的拟南芥的生长，尽管植物保持降低的木质素水平。SA介导的生长抑制可能通过干扰赤霉酸信号或反应而发生。我们的数据将SA作为生长信号通路的中心组成部分，这些信号通路要么感应通量进入单醇醇途径，要么对次生细胞壁完整性做出反应，并表明有可能在不对生长产生负面影响的情况下设计高度减少细胞壁阻力的植物。
Down-regulation of the enzyme hydroxycinnamoyl CoA: shikimate hydroxycinnamoyl transferase (HCT) in thale cress (Arabidopsis thaliana) and alfalfa (Medicago sativa) leads to strongly reduced lignin levels, reduced recalcitrance of cell walls to sugar release, but severe stunting of the plants. Levels of the stress hormone salicylic acid (SA) are inversely proportional to lignin levels and growth in a series of transgenic alfalfa plants in which lignin biosynthesis has been perturbed at different biosynthetic steps. Reduction of SA levels by genetically blocking its formation or causing its removal restores growth in HCT-down-regulated Arabidopsis, although the plants maintain reduced lignin levels. SA-mediated growth inhibition may occur via interference with gibberellic acid signaling or responsiveness. Our data place SA as a central component in growth signaling pathways that either sense flux into the monolignol pathway or respond to secondary cell-wall integrity, and indicate that it is possible to engineer plants with highly reduced cell-wall recalcitrance without negatively impacting growth.