Li Yu-Xuan, Cai Jia-Bei, Liu Xiao
College of Horticulture and Landscape Architecture, Yangzhou University, Yangzhou 225009, China.
Plants (Basel). 2025 Sep 4;14(17):2776. doi: 10.3390/plants14172776.
Sand pear is a fruit tree crop with high economic value, widely cultivated in East Asia. However, ripening fruits often suffer from high-temperature stress, which has adverse effects on the quality and yield of the fruit. In this study, we perform high-temperature treatment on mature stage 'Housui' pear fruits. The results showed that heat stress decreased fruit firmness and mineral elements, as well as lead to the flesh appearance of watercore. High temperature induces HO, MDA, and the antioxidant enzyme activity including SOD, APX, POD, and CAT were significantly increased. Transcriptome and metabolomic analyses revealed that heat stress up-regulated genes related to sucrose synthesis (SPS) while down-regulating those involved in sucrose degradation (SS and NI), resulting in sucrose accumulation. Moreover, the expression of sorbitol dehydrogenase (SDH) and sorbitol transporter (SOT) genes was markedly suppressed, leading to sorbitol accumulation and impaired transport, which promoted watercore development. High temperature also stimulated the expression of ethylene synthesis genes, accelerating abnormal ripening of fruits. In addition, high temperature decreased the accumulation of organic acid and bioactive compounds. Additionally, several antioxidant enzymes genes, five heat shock transcription factors (HSFs) and 34 heat shock protein (HSP) genes were significantly up-regulated. Together, these findings provided new insights into the transcriptional response and metabolomic reprogramming of sand pear response to high-temperature stress.
砂梨是一种具有高经济价值的果树作物，在东亚广泛种植。然而，成熟果实常遭受高温胁迫，这对果实的品质和产量产生不利影响。在本研究中，我们对成熟期的‘丰水’梨果实进行高温处理。结果表明，热胁迫降低了果实硬度和矿质元素含量，还导致果肉出现水心病。高温诱导了过氧化氢（HO）、丙二醛（MDA）的产生，包括超氧化物歧化酶（SOD）、抗坏血酸过氧化物酶（APX）、过氧化物酶（POD）和过氧化氢酶（CAT）在内的抗氧化酶活性显著增加。转录组和代谢组分析表明，热胁迫上调了与蔗糖合成相关的基因（SPS），同时下调了参与蔗糖降解的基因（SS和NI），导致蔗糖积累。此外，山梨醇脱氢酶（SDH）和山梨醇转运蛋白（SOT）基因的表达明显受到抑制，导致山梨醇积累和运输受损，从而促进了水心病的发展。高温还刺激了乙烯合成基因的表达，加速了果实的异常成熟。此外，高温降低了有机酸和生物活性化合物的积累。另外，几个抗氧化酶基因、五个热激转录因子（HSF）和34个热激蛋白（HSP）基因显著上调。总之，这些发现为砂梨对高温胁迫的转录反应和代谢组重编程提供了新的见解。
