The Arabidopsis trithorax-like factor ATX1 functions in dehydration stress responses via ABA-dependent and ABA-independent pathways
The Arabidopsis trithorax-like factor ATX1 functions in dehydration stress responses via ABA-dependent and ABA-independent pathways
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DOI：
10.1111/j.1365-313x.2011.04534.x
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发表时间：
2011-06-01
期刊：
影响因子：
7.2
通讯作者：
Fromm, Michael
中科院分区：
文献类型：
--
作者：
Ding, Yong;Avramova, Zoya;Fromm, Michael
新的证据表明，植物对环境胁迫反应的分子机制与特定的染色质修饰有关。在这里，我们证明了拟南芥类三胸因子ATX 1，三甲基化组蛋白H3在赖氨酸4（H3K4me3），参与脱水胁迫信号在脱落酸（阿坝）依赖和ABA独立的途径。ATX1功能的丧失导致atx1植物的发芽率降低、气孔开度增大、蒸腾速率加快以及对脱水胁迫的耐受性降低。这种缺陷部分是由atx1植物中阿坝生物合成减少引起的，这是由NCED3的转录水平降低引起的，NCED3编码控制阿坝产生的关键酶。脱水胁迫增加了ATX 1与NCED3的结合，并且ATX 1是脱水胁迫期间发生的NCED3转录物和核小体H3K4me3水平增加所必需的。从机制上讲，ATX 1影响RNA聚合酶II与NCED3结合的数量。通过上调NCED3转录和阿坝产生，ATX 1影响ABA调节的途径和基因。ATX1还影响ABA非依赖性基因的表达，暗示ATX1在拟南芥中的不同脱水胁迫响应机制。
P>Emerging evidence suggests that the molecular mechanisms driving the responses of plants to environmental stresses are associated with specific chromatin modifications. Here, we demonstrate that the Arabidopsis trithorax-like factor ATX1, which trimethylates histone H3 at lysine 4 (H3K4me3), is involved in dehydration stress signaling in both abscisic acid (ABA)-dependent and ABA-independent pathways. The loss of function of ATX1 results in decreased germination rates, larger stomatal apertures, more rapid transpiration and decreased tolerance to dehydration stress in atx1 plants. This deficiency is caused in part by reduced ABA biosynthesis in atx1 plants resulting from decreased transcript levels from NCED3, which encodes a key enzyme controlling ABA production. Dehydration stress increased ATX1 binding to NCED3, and ATX1 was required for the increased levels of NCED3 transcripts and nucleosomal H3K4me3 that occurred during dehydration stress. Mechanistically, ATX1 affected the quantity of RNA polymerase II bound to NCED3. By upregulating NCED3 transcription and ABA production, ATX1 influenced ABA-regulated pathways and genes. ATX1 also affected the expression of ABA-independent genes, implicating ATX1 in diverse dehydration stress-response mechanisms in Arabidopsis.