Abscisic Acid as an Internal Integrator of Multiple Physiological Processes Modulates Leaf Senescence Onset in Arabidopsis thaliana.
Abscisic Acid as an Internal Integrator of Multiple Physiological Processes Modulates Leaf Senescence Onset in Arabidopsis thaliana.
复制标题
脱落酸作为多种生理过程的内部整合剂调节拟南芥叶片衰老的发生
DOI：
10.3389/fpls.2016.00181
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发表时间：
2016
影响因子：
5.6
通讯作者：
Song CP
中科院分区：
文献类型：
--
作者：
Song Y;Xiang F;Zhang G;Miao Y;Miao C;Song CP
许多研究表明外源脱落酸（阿坝）促进叶片的脱落和衰老。然而，由于缺乏遗传学证据，ABA在植物衰老中的功能尚未明确。在此，通过叶绿素荧光成像技术筛选出的两叶型早衰突变体eas 1 -1和eas 1 -2在植物生长的早期表现出比野生型高的光合能力。基因定位结果表明，eas 1 -1和eas 1 -2是两个新的ABA 2等位突变体。在非胁迫条件下，与野生型相比，eas 1突变体导致植株矮小、发芽早、气孔开度大和叶片衰老早。流式细胞仪检测表明，eas 1突变体叶片在30天后的细胞凋亡率高于野生型。在eas 1突变体植株生长的早期阶段，几个衰老相关基因的转录水平显著增加，尤其是SAG 12。更重要的是，由于EAS 1的突变，ABA激活的质膜钙通道活性和诱导的保卫细胞胞浆钙浓度的增加被抑制。相比之下，eas 1突变体失去叶绿素和离子泄漏显着快于野生型下与钙通道阻滞剂治疗。因此，我们的研究结果表明，内源阿坝水平是一个重要的因素控制叶片衰老的开始，通过Ca 2+信号。
Many studies have shown that exogenous abscisic acid (ABA) promotes leaf abscission and senescence. However, owing to a lack of genetic evidence, ABA function in plant senescence has not been clearly defined. Here, two-leaf early-senescence mutants (eas) that were screened by chlorophyll fluorescence imaging and named eas1-1 and eas1-2 showed high photosynthetic capacity in the early stage of plant growth compared with the wild type. Gene mapping showed that eas1-1 and eas1-2 are two novel ABA2 allelic mutants. Under unstressed conditions, the eas1 mutations caused plant dwarf, early germination, larger stomatal apertures, and early leaf senescence compared with those of the wild type. Flow cytometry assays showed that the cell apoptosis rate in eas1 mutant leaves was higher than that of the wild type after day 30. A significant increase in the transcript levels of several senescence-associated genes, especially SAG12, was observed in eas1 mutant plants in the early stage of plant growth. More importantly, ABA-activated calcium channel activity in plasma membrane and induced the increase of cytoplasmic calcium concentration in guard cells are suppressed due to the mutation of EAS1. In contrast, the eas1 mutants lost chlorophyll and ion leakage significant faster than in the wild type under treatment with calcium channel blocker. Hence, our results indicate that endogenous ABA level is an important factor controlling the onset of leaf senescence through Ca2+ signaling.