HD-ZIP is a unique type of transcription factor in plants, which are closely linked to the regulation of plant growth and development, the response to abiotic stress, and disease resistance. However, there is little known about the HD-ZIP gene family of pepper. In this study, 40 HD-ZIP family members were analyzed in the pepper genome. The analysis indicated that the introns number of Ca-HD-ZIP varied from 1 to 17; the number of amino acids was between 119 and 841; the theoretical isoelectric point was between 4.54 and 9.85; the molecular weight was between 14.04 and 92.56; most of them were unstable proteins. The phylogenetic tree divided CaHD-ZIP into 4 subfamilies; 40 CaHD-ZIP genes were located on different chromosomes, and all of them contained the motif 1; two pairs of CaHD-ZIP parallel genes of six paralogism genes were fragment duplications which occurred in 58.28~88.24 million years ago. There were multiple pressure-related action elements upstream of the start codon of the HD-Z-IP family. Protein interaction network proved to be coexpression phenomenon between ATML1 (CaH-DZ22, CaHDZ32) and At4g048909 (CaHDZ12, CaHDZ31), and three regions of them were highly homology. The expression level of CaHD-ZIP gene was different with tissues and developmental stages, which suggested that CaHD-ZIP may be involved in biological functions during pepper progress. In addition, Pepper HD-ZIP I and II genes played a major role in salt stress. CaHDZ03, CaHDZ 10, CaHDZ17, CaHDZ25, CaHDZ34, and CaHDZ35 were significantly induced in response to salt stress. Notably, the expression of CaHDZ07, CaHDZ17, CaHDZ26, and CaHDZ30, homologs of Arabidopsis AtHB12 and AtHB7 genes, was significantly upregulated by salt stresses. CaHDZ03 possesses two closely linked ABA action elements, and its expression level increased significantly at 4 h under salt stress. qRT-P-CR and transcription analysis showed that the expression of CaHDZ03 and CaHDZ10 was upregulated under short-term salt stress, but CaHDZ10 was downregulated with long-term salt stress, which provided a theoretical basis for research the function of Ca-HDZIP in response to abiotic stress.

中文翻译：

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辣椒盐胁迫下HD-ZIP基因家族的全基因组表征和表达分析

HD-ZIP是植物中一种独特的转录因子，与植物生长发育，对非生物胁迫的反应以及抗病性密切相关。但是，关于辣椒的HD-ZIP基因家族知之甚少。在这项研究中，在辣椒基因组中分析了40个HD-ZIP家族成员。分析表明，Ca-HD-ZIP的内含子数在1至17之间变化。氨基酸数量在119至841之间；理论等电点在4.54和9.85之间；分子量在14.04至92.56之间；他们大多数是不稳定的蛋白质。系统发育树将CaHD-ZIP分为4个亚科。40个CaHD-ZIP基因位于不同的染色体上，所有基因都含有1型基序。两对6个旁系同源基因的CaHD-ZIP平行基因是片段重复，发生在58.28〜88.24百万年前。HD-Z-IP系列起始密码子的上游有多个与压力有关的作用元件。蛋白质相互作用网络被证明是ATML1（CaH-DZ22，CaHDZ32）和At4g048909（CaHDZ12，CaHDZ31）之间的共表达现象，并且它们的三个区域具有高度同源性。CaHD-ZIP的表达水平该基因随组织和发育阶段的不同而不同，提示CaHD-ZIP可能与辣椒发育过程中的生物学功能有关。另外，Pepper HD-ZIP I和II基因在盐胁迫中起主要作用。CaHDZ03，CaHDZ 10，CaHDZ17，CaHDZ25，CaHDZ34和CaHDZ35响应盐胁迫而显着诱导。值得注意的是，表达CaHDZ07，CaHDZ17，CaHDZ26，和CaHDZ30，拟南芥的同源物AtHB12和AtHB7基因，是通过显著盐胁迫上调。钙HDZ03具有两个紧密联系的ABA作用元件，并且在盐胁迫下4小时其表达水平显着增加。qRT-P-CR和转录分析表明，CaHDZ03和CaHDZ10的表达在短期盐胁迫下被上调，而CaHDZ10在长期盐胁迫下被下调，这为研究Ca-HDZIP在海盐中的功能提供了理论基础。对非生物胁迫的反应。