当前位置: X-MOL 学术J. Plant Physiol. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Arabidopsis thaliana Branching Enzyme 1 is Essential for Amylopectin Biosynthesis and Cesium Tolerance
Journal of Plant Physiology ( IF 4.3 ) Pub Date : 2020-09-01 , DOI: 10.1016/j.jplph.2020.153208
Junxia Zhang 1 , Ju Yang 2 , Ting Zhang 3 , Qihui Yang 1 , Hairong Gao 1 , Hongmei Cheng 4 , Huiqing Jin 5 , Yufen Wang 1 , Zhi Qi 2
Affiliation  

Arabidopsis thaliana BRANCHING ENZYME 1 (AtBE1) is a chloroplast-localized embryo-lethal gene previously identified in knockout mutants. AtBE1 is thought to function in carbohydrate metabolism; however, this has not been experimentally demonstrated. Chlorosis is a typical symptom of cesium (Cs) toxicity in plants. The genetic target of Cs toxicity is largely unknown. Here, we isolated a Cs+-tolerant and chlorophyll-defective Arabidopsis ethyl methanesulfonate (EMS) mutant, atbe1-5. Mapping by sequencing and genetic complementation confirmed that a single amino acid change (P749S) in a random coil motif of AtBE1 confers the mutant's Cs+-tolerant and chlorophyll-defective phenotype. An isothermal titration calorimetry assay determined that the 749th residue is the Cs+-binding site and hence likely the target of Cs+ toxicity. We hypothesized that binding of Cs+ to the 749th residue of AtBE1 inhibits the enzyme's activity and confers Cs+ toxicity, which in turn reduces photosynthetic efficiency. In support with this hypothesis, atbe1-5 leaves have a reduced photosynthetic efficiency, and their amylose and amylopectin contents are ∼60 % and ∼1%, respectively, of those in Col-0 ecotype leaves. Leaves of the mutant have a lower sucrose, but higher maltose, concentration than those of Col-0. This study demonstrated that AtBE1 is an essential gene for amylopectin and amylose biosynthesis, as well as the target of Cs+ toxicity; therefore, it can serve as a genetic locus for engineering plants to extract Cs+ from contaminated soil while maintaining growth.

中文翻译:

拟南芥分支酶 1 对支链淀粉生物合成和铯耐受性至关重要

拟南芥分支酶 1 (AtBE1) 是先前在敲除突变体中发现的叶绿体定位的胚胎致死基因。AtBE1 被认为在碳水化合物代谢中起作用;然而,这还没有得到实验证明。褪绿是植物中铯 (Cs) 毒性的典型症状。Cs 毒性的遗传靶点在很大程度上是未知的。在这里,我们分离了一个 Cs + 耐受和叶绿素缺陷拟南芥甲磺酸乙酯 (EMS) 突变体,atbe1-5。通过测序和遗传互补作图证实,AtBE1 随机卷曲基序中的单个氨基酸变化 (P749S) 赋予突变体的 Cs+耐受和叶绿素缺陷表型。等温滴定量热测定确定第 749 个残基是 Cs+ 结合位点,因此可能是 Cs+ 毒性的目标。我们假设 Cs+ 与 AtBE1 的第 749 个残基的结合会抑制酶的活性并赋予 Cs+ 毒性,从而降低光合效率。支持这一假设的是,atbe1-5 叶片的光合效率降低,它们的直链淀粉和支链淀粉含量分别为 Col-0 生态型叶片的 60% 和 1%。与 Col-0 相比,突变体的叶子具有较低的蔗糖浓度,但较高的麦芽糖浓度。该研究表明,AtBE1 是支链淀粉和直链淀粉生物合成的必需基因,也是 Cs+ 毒性的靶点;因此,它可以作为工程植物在保持生长的同时从污染土壤中提取Cs+的遗传位点。从而降低光合效率。支持这一假设的是,atbe1-5 叶片的光合效率降低,它们的直链淀粉和支链淀粉含量分别为 Col-0 生态型叶片的 60% 和 1%。与 Col-0 相比,突变体的叶子具有较低的蔗糖浓度,但较高的麦芽糖浓度。该研究表明,AtBE1 是支链淀粉和直链淀粉生物合成的必需基因,也是 Cs+ 毒性的靶点;因此,它可以作为工程植物在保持生长的同时从污染土壤中提取Cs+的遗传位点。从而降低光合效率。支持这一假设的是,atbe1-5 叶片的光合效率降低,它们的直链淀粉和支链淀粉含量分别为 Col-0 生态型叶片的 60% 和 1%。与 Col-0 相比,突变体的叶子具有较低的蔗糖浓度,但较高的麦芽糖浓度。该研究表明,AtBE1 是支链淀粉和直链淀粉生物合成的必需基因,也是 Cs+ 毒性的靶点;因此,它可以作为工程植物在保持生长的同时从污染土壤中提取Cs+的遗传位点。与 Col-0 相比,突变体的叶子具有较低的蔗糖浓度,但较高的麦芽糖浓度。该研究表明,AtBE1 是支链淀粉和直链淀粉生物合成的必需基因,也是 Cs+ 毒性的靶点;因此,它可以作为工程植物在保持生长的同时从污染土壤中提取Cs+的遗传位点。与 Col-0 相比,突变体的叶子具有较低的蔗糖浓度,但较高的麦芽糖浓度。该研究表明,AtBE1 是支链淀粉和直链淀粉生物合成的必需基因,也是 Cs+ 毒性的靶点;因此,它可以作为工程植物在保持生长的同时从污染土壤中提取Cs+的遗传位点。
更新日期:2020-09-01
down
wechat
bug