Qinzhou Branch of Guangxi Academy of Agricultural Sciences/Qinzhou Institute of Agricultural Sciences, Qinzhou, China.
Institute of Horticulture, Guangxi Academy of Agricultural Sciences, Nanning, China.
PeerJ. 2023 Feb 2;11:e14839. doi: 10.7717/peerj.14839. eCollection 2023.
High temperature in summer is an unfavorable factor for passion fruit (), which can lead to restricted growth, short flowering period, few flower buds, low fruit setting rate, severe fruit drop, and more deformed fruit. To explore the molecular physiology mechanism of passion fruit responding to high-temperature stress, we use 'Zhuangxiang Mibao', a hybrid passion fruit cultivar, as the test material. Several physiological indicators were measured and compared between high-temperature (average temperature 38 °C) and normal temperature (average temperature 25 °C) conditions, including photosynthesis, chlorophyll fluorescence parameters, peroxidase activity (POD), superoxide dismutase activity (SOD) and malondialdehyde content. We performed RNA-seq analysis combined with biochemistry experiment to investigate the gene and molecular pathways that respond to high-temperature stress. The results showed that some physiological indicators in the high-temperature group, including the net photosynthetic rate, stomatal conductance, intercellular CO concentration, transpiration rate, and the maximum chemical quantum yield of photosystemII (PSII), were significantly lower than those of the control group. Malondialdehyde content was substantially higher than the control group, while superoxide dismutase and superoxide dismutase activities decreased to different degrees. Transcriptome sequencing analysis showed that 140 genes were up-regulated and 75 genes were down-regulated under high-temperature stress. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) annotation analysis of differentially expressed genes revealed many metabolic pathways related to high-temperature stress. Further investigation revealed that 30 genes might be related to high-temperature stress, such as , (), (), and (), which have also been reported in other species. The results of real-time fluorescence quantitative PCR and RNA-seq of randomly selected ten genes are consistent, which suggests that the transcriptome sequencing results were reliable. Our study provides a theoretical basis for the mechanism of passion fruit response to high-temperature stress. Also, it gives a theoretical basis for the subsequent breeding of new heat-resistant passion fruit varieties.
高温是百香果生长的不利因素，会导致百香果生长受限、开花期缩短、花蕾少、坐果率低、落果严重、果实畸形增多。为了探究百香果响应高温胁迫的分子生理机制，我们以杂交百香果品种‘壮乡蜜宝’为试验材料，在高温（平均温度 38°C）和常温（平均温度 25°C）条件下，测量并比较了几个生理指标，包括光合作用、叶绿素荧光参数、过氧化物酶活性（POD）、超氧化物歧化酶活性（SOD）和丙二醛含量。我们进行了 RNA-seq 分析，并结合生物化学实验，研究了响应高温胁迫的基因和分子途径。结果表明，高温组的一些生理指标，如净光合速率、气孔导度、胞间 CO 浓度、蒸腾速率和 PSII 最大光化学量子产量，均显著低于对照组。丙二醛含量显著高于对照组，而超氧化物歧化酶和超氧化物歧化酶活性则不同程度地降低。转录组测序分析表明，140 个基因在高温胁迫下上调，75 个基因下调。差异表达基因的基因本体（GO）和京都基因与基因组百科全书（KEGG）注释分析表明，许多与高温胁迫相关的代谢途径被激活。进一步研究发现，30 个基因可能与高温胁迫有关，如 、 、 、 等，这些基因在其他物种中也有报道。随机选择的十个基因的实时荧光定量 PCR 和 RNA-seq 结果一致，这表明转录组测序结果是可靠的。本研究为百香果响应高温胁迫的机制提供了理论依据，也为后续培育新的耐热百香果品种提供了理论依据。
