Department of Plant Physiology and Biotechnology, Faculty of Biology, University of Gdansk, Gdansk, Poland.
Department of Biotechnology, Faculty of Agriculture, Atatürk University, Erzurum, 25240, Turkey.
Physiol Plant. 2023 Mar;175(2):e13889. doi: 10.1111/ppl.13889.
The synthesis of capsaicinoids occurs in the placenta of the fruits of pungent peppers. However, the mechanism of capsaicinoids' biosynthesis in pungent peppers under salinity stress conditions is unknown. The Habanero and Maras genotypes, the hottest peppers in the world, were chosen as plant material for this study, and they were grown under normal and salinity (5 dS m ) conditions. The results showed that salinity stress harmed plant growth but increased the capsaicin content by 35.11% and 37.00%, as well as the dihydrocapsaicin content by 30.82% and 72.89% in the fruits of the Maras and Habanero genotypes, respectively, at 30 days after planting. The expression analysis of key genes in capsaicinoids biosynthesis revealed that the PAL1, pAMT, KAS, and PUN1 genes were overexpressed in the vegetative and reproductive organs of pungent peppers under normal conditions. However, under salinity stress, overexpression of PAL1, pAMT, and PUN1 genes was identified in the roots of both genotypes, which was accompanied by an increase in capsaicin and dihydrocapsaicin content. The findings showed that salinity stress caused an enhancement in the capsaicin and dihydrocapsaicin contents in the roots, leaves, and fruits of pungent peppers. Nonetheless, it was found that the production of capsaicinoids is generally not restricted to the fruits of pungent peppers.
辣椒素类物质的合成发生在辣味辣椒果实的胎座中。然而，在盐胁迫条件下，辣味辣椒中辣椒素类物质生物合成的机制尚不清楚。本研究选用世界上最辣的哈瓦那辣椒和马拉斯辣椒作为植物材料，在正常和盐度（5 dS m ）条件下进行种植。结果表明，盐胁迫会损害植物生长，但会分别使马拉斯和哈瓦那辣椒果实中的辣椒素含量增加 35.11%和 37.00%，二氢辣椒素含量增加 30.82%和 72.89%，种植 30 天后。辣椒素生物合成关键基因的表达分析表明，PAL1、pAMT、KAS 和 PUN1 基因在正常条件下的辣味辣椒营养和生殖器官中过表达。然而，在盐胁迫下，两种基因型的根中均发现 PAL1、pAMT 和 PUN1 基因的过表达，同时伴随着辣椒素和二氢辣椒素含量的增加。研究结果表明，盐胁迫会增加辣味辣椒根、叶和果实中辣椒素和二氢辣椒素的含量。尽管如此，人们发现辣椒素类物质的产生通常不限于辣味辣椒的果实。
