The DnaJ proteins play critical roles in plant development and stress responses. Recently, seventy-six DnaJ genes were identified through a comprehensive bioinformatics analysis in the pepper genome. However, there were no reports on understanding of phylogenetic relationships and diverse expression profile of pepper DnaJ genes to date. Herein, we performed the systemic analysis of the phylogenetic relationships and expression profile of pepper DnaJ genes in different tissues and in response to both abiotic stress and plant hormones. Phylogenetic analysis showed that all the pepper DnaJ genes were grouped into 7 sub-families (sub-family I, II, III, IV, V, VI and VII) according to sequence homology. The expression of pepper DnaJs in different tissues revealed that about 38% (29/76) of pepper DnaJs were expressed in at least one tissue. The results demonstrate the potentially critical role of DnaJs in pepper growth and development. In addition, to gain insight into the expression difference of pepper DnaJ genes in placenta between pungent and non-pungent, their expression patterns were also analyzed using RNA-seq data and qRT-PCR. Comparison analysis revealed that eight genes presented distinct expression profiles in pungent and non-pungent pepper. The CaDnaJs co-expressed with genes involved in capsaicinoids synthesis during placenta development. What is more, our study exposed the fact that these eight DnaJ genes were probably regulated by stress (heat, drought and salt), and were also regulated by plant hormones (ABA, GA3, MeJA and SA). In summary, these results showed that some DnaJ genes expressed in placenta may be involved in plant response to abiotic stress during biosynthesis of compounds related with pungency. The study provides wide insights to the expression profiles of pepper DanJ genes and contributes to our knowledge about the function of DnaJ genes in pepper.

中文翻译：

---

全局分析辣椒中辣椒素合成中涉及的DnaJ基因家族成员的表达谱。

DnaJ蛋白在植物发育和胁迫响应中起关键作用。最近，通过对辣椒基因组的全面生物信息学分析，鉴定出76个DnaJ基因。然而，迄今为止，尚无关于胡椒DnaJ基因的系统发生关系和多样化表达谱的了解的报道。在本文中，我们进行了系统分析，分析了辣椒DnaJ基因在不同组织中的系统发育关系和表达谱，并响应了非生物胁迫和植物激素。系统发育分析表明，根据序列同源性，所有的辣椒DnaJ基因都被分为7个亚家族（I，II，III，IV，V，VI和VII亚家族）。胡椒DnaJs在不同组织中的表达表明，在至少一种组织中表达了约38％（29/76）的胡椒DnaJs。结果表明，DnaJs在辣椒生长发育中具有潜在的关键作用。此外，为了深入了解胡椒DnaJ基因在刺激性和非刺激性之间在胎盘中的表达差异，还使用RNA-seq数据和qRT-PCR分析了它们的表达模式。比较分析显示，在辛辣和非辛辣辣椒中，八个基因呈现出不同的表达特征。CaDnaJs与胎盘发育过程中涉及辣椒素合成的基因共表达。而且，我们的研究揭示了以下事实：这八个DnaJ基因可能受胁迫（高温，干旱和盐分）调控，还受植物激素（ABA，GA3，MeJA和SA）调控。综上所述，这些结果表明，在与刺激性有关的化合物的生物合成过程中，胎盘中表达的某些DnaJ基因可能参与了植物对非生物胁迫的反应。该研究为辣椒DanJ基因的表达谱提供了广泛的见识，并有助于我们了解DnaJ基因在辣椒中的功能。