Arabidopsis SHMT1, a serine hydroxymethyltransferase that functions in the photorespiratory pathway influences resistance to biotic and abiotic stress
Arabidopsis SHMT1, a serine hydroxymethyltransferase that functions in the photorespiratory pathway influences resistance to biotic and abiotic stress
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DOI：
10.1111/j.1365-313x.2004.02311.x
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发表时间：
2005-02-01
期刊：
影响因子：
7.2
通讯作者：
Castresana, C
中科院分区：
文献类型：
--
作者：
Moreno, JI;Martín, R;Castresana, C
我们发现，隐性突变shmt1-1在各种环境条件下导致细胞死亡的异常调节，导致黄化和坏死性病变的形成。水杨酸诱导基因和H_2O_2解毒相关基因在shmt1-1植株中结构性表达，与病斑严重程度直接相关。Shmt1-1突变体比对照植株更容易受到生物营养型和坏死型病原菌的侵染，在高比例的病叶中出现严重的侵染症状。此外，携带shmt1-1或功能丧失的shmt1-2等位基因的突变体在盐胁迫下比野生型植株更小，表现出更大的叶绿素损失和更大的过氧化氢积累。SHMT1是基于MAP克隆的，编码与光呼吸途径有关的丝氨酸羟甲基转移酶(SHMT1)。我们的结果表明，这种酶活性在控制高光和盐等非生物胁迫引起的细胞损伤和限制病原菌诱导的细胞死亡方面发挥了关键作用，支持了光呼吸是植物耗散机制的一部分，以减少叶绿体中活性氧物种(ROS)的产生，减轻氧化损伤。此外，这里的结果表明，虽然ROS的产生是过敏性防御反应的重要组成部分，但这些有毒化合物的过度积累损害了细胞死亡的遏制，并抵消了植物防御系统限制病原体侵染的有效性。
We found that a recessive mutation, shmt1-1, causes aberrant regulation of cell death resulting in chlorotic and necrotic lesion formation under a variety of environmental conditions. Salicylic acid-inducible genes and genes involved in H2O2 detoxification were expressed constitutively in shmt1-1 plants in direct correlation with the severity of the lesions. The shmt1-1 mutants were more susceptible than control plants to infection with biotrophic and necrotrophic pathogens, developing severe infection symptoms in a high percentage of infected leaves. In addition, mutants carrying shmt1-1 or a loss-of-function shmt1-2 allele, were smaller and showed a greater loss of chlorophyll and greater accumulation of H2O2 than wild-type plants when subjected to salt stress. SHMT1 was map-based cloned and found to encode a serine hydroxymetyltransferase (SHMT1) involved in the photorespiratory pathway. Our results indicate that this enzymatic activity plays a critical role in controlling the cell damage provoked by abiotic stresses such as high light and salt and in restricting pathogen-induced cell death, supporting the notion that photorespiration forms part of the dissipatory mechanisms of plants to minimize production of reactive oxygen species (ROS) at the chloroplast and to mitigate oxidative damage. Moreover, results shown here indicate that whereas production of ROS is an essential component of the hypersensitive defense response, the excessive accumulation of these toxic compounds impairs cell death containment and counteracts the effectiveness of the plant defenses to restrict pathogen infection.