College of Horticulture, Gansu Agricultural University, Yingmen Village, Anning District, Lanzhou, 730070, China.
BMC Plant Biol. 2024 Sep 30;24(1):907. doi: 10.1186/s12870-024-05622-3.
The growth and yield of pepper, a typical temperature-loving vegetable, are limited by low-temperature environments. Using low-temperature sensitive 'Hangjiao No. 4' (Capsicum annuum L.) as experimental material, this study analyzed the changes in plant growth and photosynthesis under different treatments: normal control (NT), low-temperature stress alone (LT), low-temperature stress in strigolactone pretreated plants (SL_LT), and low-temperature stress in strigolactone biosynthesis inhibitor pretreated plants (Tis_LT).
SL pretreatment increased the net photosynthetic rate (Pn) and PSII actual photochemical efficiency (φPSII), reducing the inhibition of LT on the growth of pepper by 17.44% (dry weight of shoot). Due to promoting the accumulation of carotenoids, such as lutein, and the de-epoxidation of the xanthophyll cycle [(Z + A)/(Z + A + V)] by strigolactone after long-term low-temperature stress (120 h), non-photochemical quenching (NPQ) of pepper was increased to reduce the excess excitation energy [(1-qP)/NPQ] and the photoinhibition degree (Fv/Fm) of pepper seedlings under long-term low-temperature stress was alleviated. Twelve cDNA libraries were constructed from pepper leaves by transcriptome sequencing. There were 8776 differentially expressed genes (DEGs), including 4473 (51.0%) upregulated and 4303 (49.0%) downregulated genes. Gene ontology pathway annotation showed that based on LT, the DEGs of SL_LT and Tis_LT were significantly enriched in the cellular component, which is mainly related to the photosystem and thylakoids. Further analysis of the porphyrin and chlorophyll biosynthesis, carotenoid biosynthesis, photosynthesis-antenna protein, and photosynthetic metabolic pathways and the Calvin cycle under low-temperature stress highlighted 18, 15, 21, 29, and 31 DEGs for further study, which were almost all highly expressed under SL_LT treatment and moderately expressed under LT treatment, whereas Tis_LT showed low expression.
The positive regulatory effect of SLs on the low-temperature tolerance of pepper seedlings was confirmed. This study provided new insights for the development of temperature-tolerant pepper lines through breeding programs.
辣椒是一种典型的喜温蔬菜，其生长和产量受到低温环境的限制。本研究以低温敏感型‘杭椒 4 号’（Capsicum annuum L.）为实验材料，分析了在不同处理下植物生长和光合作用的变化：正常对照（NT）、单独低温胁迫（LT）、经独脚金内酯预处理的植物的低温胁迫（SL_LT）和经独脚金内酯生物合成抑制剂预处理的植物的低温胁迫（Tis_LT）。
SL 预处理提高了净光合速率（Pn）和 PSII 实际光化学效率（φPSII），降低了 LT 对辣椒生长的抑制作用 17.44%（地上部干重）。由于独脚金内酯在长期低温胁迫（120 h）后促进了叶黄素等类胡萝卜素的积累和叶黄素循环的去氧化（[Z + A]/[Z + A + V]），胡椒的非光化学猝灭（NPQ）增加，以减少长期低温胁迫下胡椒幼苗的过剩激发能[（1-qP）/NPQ]和光抑制程度（Fv/Fm）。通过转录组测序构建了 12 个辣椒叶片 cDNA 文库。共鉴定到 8776 个差异表达基因（DEGs），其中 4473 个（51.0%）上调，4303 个（49.0%）下调。基因本体通路注释表明，基于 LT，SL_LT 和 Tis_LT 的 DEGs 显著富集在细胞成分中，主要与光系统和类囊体有关。进一步分析低温胁迫下的卟啉和叶绿素生物合成、类胡萝卜素生物合成、光合作用天线蛋白和光合作用代谢途径以及卡尔文循环，突出了 18、15、21、29 和 31 个 DEGs 供进一步研究，这些基因在 SL_LT 处理下几乎全部高度表达，在 LT 处理下中度表达，而 Tis_LT 则表达较低。
证实了独脚金内酯对辣椒幼苗低温胁迫的正向调节作用。本研究为通过育种计划开发耐温辣椒品系提供了新的见解。
