Zhang Fan, Xin Ming, Yu Siqi, Liu Dong, Zhou Xiuyan, Qin Zhiwei
College of Horticulture and Landscape Architecture, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Northeast Region), Northeast Agricultural University, Harbin, China.
Front Plant Sci. 2019 Jul 4;10:871. doi: 10.3389/fpls.2019.00871. eCollection 2019.
Propamocarb (PM), a carbamate fungicide, can effectively control downy mildew on cucumber. However, due to the large-scale and high-dose use of this fungicide, PM residues have become a major problem in cucumber production. In this report, the cucumber cultivar "D0351" (with the lowest residual PM content) and the cucumber cultivar "D9320" (with the highest residual PM content) were used as experimental materials. The candidate gene , which is related to a low residual PM content in cucumber, was screened by high-throughput tag-sequencing (Tag-Seq) and PM analysis, and its role in reducing PM residue in cucumber was explored. was cloned and obtained. This gene contains an open reading frame of 1026 bp, encodes 341 amino acids and contains 3 Mito-carr domains. The encoded protein is a hydrophobic protein with 4 distinct transmembrane structures but no signal peptide cleavage sites. The subcellular localization of the protein is the cytoplasm. Evolutionary tree analysis showed that had the highest homology to a gene from the melon L. (XM_008464998.2). The core elements of the promoter include acting elements, such as those related to salicylic acid (SA), jasmonic acid (JA), gibberellin (GA), and abscisic acid (ABA). Following PM treatment, was significantly upregulated at most time points in different parts of the fruit, leaf, stem and root of "D0351," while expression was downregulated at most time points in the fruit, leaf and stem of "D9320." The order of the expression levels in different cucumber organs was as follows: fruit>leaf > stem > root. was specifically expressed in the stems and leaves of "D0351." The PM residues in (+)-overexpressing T0 and T1 cucumber fruits were significantly lower than those in the wild type, while the PM residues in (-)-overexpressing T0 and T1 cucumber fruits were significantly higher. The qRT-PCR results showed that can respond to biotic and abiotic stresses, actively respond to PM treatment and play a role in reducing PM residues in cucumber fruits.
霜霉威（PM）是一种氨基甲酸酯类杀菌剂，能有效防治黄瓜霜霉病。然而，由于这种杀菌剂的大规模高剂量使用，PM残留已成为黄瓜生产中的一个主要问题。在本报告中，以黄瓜品种“D0351”（PM残留量最低）和黄瓜品种“D9320”（PM残留量最高）为实验材料。通过高通量标签测序（Tag-Seq）和PM分析筛选出与黄瓜中低PM残留量相关的候选基因，并探索其在降低黄瓜中PM残留方面的作用。该基因被克隆并获得。该基因含有一个1026 bp的开放阅读框，编码341个氨基酸，包含3个线粒体载体结构域。编码的蛋白质是一种疏水蛋白，有4个不同的跨膜结构，但没有信号肽切割位点。该蛋白质的亚细胞定位是细胞质。进化树分析表明，该基因与甜瓜L.的一个基因（XM_008464998.2）同源性最高。启动子的核心元件包括作用元件，如与水杨酸（SA）、茉莉酸（JA）、赤霉素（GA）和脱落酸（ABA）相关的元件。在PM处理后，“D0351”果实、叶片、茎和根的不同部位在大多数时间点上该基因显著上调，而在“D9320”果实、叶片和茎的大多数时间点上表达下调。不同黄瓜器官中的表达水平顺序如下：果实>叶片>茎>根。该基因在“D0351”的茎和叶中特异性表达。过表达（+）该基因的T0和T1代黄瓜果实中的PM残留量显著低于野生型，而过表达（-）该基因的T0和T1代黄瓜果实中的PM残留量显著更高。qRT-PCR结果表明，该基因能响应生物和非生物胁迫，积极响应PM处理，并在降低黄瓜果实中PM残留方面发挥作用。
