Cucumbers are frequently subjected to heat stress (HS) during the summer, which severely limits their growth and fruit yield and quality. Soil arbuscular mycorrhizal fungi (AMF) can enhance the abiotic stress tolerance of host plants, but it is unclear whether and how soil arbuscular mycorrhizal fungi (AMF) enhance the HS tolerance of cucumber. This work aimed to assess the effects of an arbuscular mycorrhizal fungus, Diversispora versiformis, on plant growth, leaf gas exchange, and expressions of plasma membrane intrinsic proteins (PIPs) and heat shock protein 70 (Hsp70) genes in roots of cucumber under HS (38 °C/30 °C, day/night temperature, 16 h/8 h) and suitable temperature (ST) (25 °C/18 °C, day/night temperature, 16 h/8 h) conditions. The HS treatment significantly decreased root mycorrhizal colonization and soil mycelium length by 0.26- and 0.55-fold, respectively, compared with the ST treatment. The biomass inhibition of cucumber by HS versus ST was more pronounced in uninoculated plants than inoculated plants. Inoculation with D. versiformis, however, significantly increased cucumber biomass and leaf gas exchange under both ST and HS conditions when compared to the uninoculated treatment. The HS treatment had almost no effect on or down-regulated the expression of CsHsp70s and CsPIPs genes in uninoculated plants, while most CsHsp70s and CsPIPs gene expressions were up-regulated in inoculated plants under HS versus ST conditions, suggesting the active heat resistance of mycorrhizal plants. Additionally, under ST conditions, D. versiformis up-regulated CsHsp70–11, CsPIP1;2, and CsPIP2;6 expressions. Under HS conditions, D. versiformis increased the expression of 11 of 12 CsHsp70s by 1.17‒6.14 folds as well as 12 of 14 CsPIPs by 1.82‒144.43 folds, with CsPIP1.5 and CsPIP2;7 up-regulated up to 144.43- and 82.46-fold, respectively. It is concluded that D. versiformis-inoculated cucumbers exhibited higher heat tolerance than uninoculated plants, associated with up-regulated expression of most CsHsp70s and CsPIPs genes.

黄瓜在夏季经常受到热胁迫 (HS)，这严重限制了它们的生长以及果实产量和品质。土壤丛枝菌根真菌（AMF）可以增强寄主植物的非生物胁迫耐受性，但土壤丛枝菌根真菌（AMF）是否以及如何增强黄瓜的HS耐受性尚不清楚。这项工作旨在评估丛枝菌根真菌Diversispora versiformis对植物生长、叶片气体交换以及质膜内在蛋白 ( PIPs ) 和热休克蛋白 70 ( Hsp70)表达的影响) HS（38 °C/30 °C，昼夜温度，16 h/8 h）和适宜温度（ST）（25 °C/18 °C，昼夜温度，16 h）下黄瓜根中的基因/8 h) 条件。与 ST 处理相比，HS 处理显着降低了根菌根定植和土壤菌丝体长度，分别减少了 0.26 倍和 0.55 倍。HS 与 ST 对黄瓜的生物量抑制在未接种植物中比接种植物更明显。然而，与未接种处理相比，在 ST 和 HS 条件下接种D. versiformis显着增加了黄瓜生物量和叶片气体交换。HS处理对CsHsp70s和CsPIPs的表达几乎没有影响或下调未接种植物中的基因，而大多数CsHsp70s和CsPIPs基因表达在 HS 与 ST 条件下在接种植物中上调，表明菌根植物具有活跃的耐热性。此外，在 ST 条件下，D. versiformis上调了CsHsp70–11、CsPIP1;2和CsPIP2;6 的表达。在 HS 条件下，D. versiformis将 12 个CsHsp70中的 11 个的表达增加1.17-6.14 倍，将 14 个CsPIP中的 12 个的表达增加 1.82-144.43 倍，CsPIP1.5和CsPIP2;7上调至 144.43- 和 82.46 -分别折叠。结论是D. versiformis接种的黄瓜比未接种的植物表现出更高的耐热性，这与大多数CsHsp70s和CsPIPs基因的上调表达有关。