The frequent occurrence of extreme weather events has brought forth significant challenges to the future development of agriculture, and it is imperative to enhance crop resilience to extreme events. In this study, the 16S rRNA sequences and internal transcribed spacers were examined, and non-targeted metabolomics was conducted to characterize variations in summer maize crop rhizosphere microbial diversity and metabolites under drought (DS), heat (HS), and combined drought and heat stress (DHS). After 15 days of beginning stress, plants treated with DHS exhibited a 51.7% reduction in aboveground biomass and 34.5% reduction in root biomass compared to the control. Further, under DHS, Gemmatimonadota had a greater relative abundance in contrast to when exposed to either DS or HS, under DS, Actinobacteriota (16.1%) had the highest relative abundances. When exposed to HS in contrast to the other two stress treatments, the Basidiomycota (31.2%) relative abundance became significantly elevated. Metabolites, consisting of phenol ethers, fatty acyls, organooxygen compounds, allyl-type 1,3-dipolar organic molecules and organic nitro compounds, were differentially abundant across different treatments. Pathway analysis highlighted the up-regulation of ABC transporters, penicillin/cephalosporin biosynthesis, and valine/leucine/isoleucine biosynthesis pathways when exposed to either DHS compared to DS or HS. Overall, these findings suggest that DHS would stimulate the secretion of L-valine by the roots, thereby facilitating the recruitment of Gemmatimonadota and improving nitrate and ammonium absorption by roots under DHS. In brief, the results offer significant insights into the interactions between microbes and plants, as well as the potential to harness beneficial microbial communities to improve maize resilience and productivity under different types of abiotic stress.

中文翻译：

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土壤养分、根际代谢物和微生物之间的动态相互作用影响夏玉米的干旱和热应激反应

极端天气事件频发，给农业未来发展带来重大挑战，增强农作物抵御极端事件的能力势在必行。在这项研究中，检查了16S rRNA序列和内转录间隔区，并进行非靶向代谢组学来表征干旱（DS）、高温（HS）​​以及干旱和高温联合作用下夏玉米作物根际微生物多样性和代谢物的变化压力（国土安全部）。开始胁迫 15 天后，与对照相比，用 DHS 处理的植物地上生物量减少了 51.7%，根生物量减少了 34.5%。此外，与暴露于 DS 或 HS 时相比，在 DHS 下，Gemmatimonadota 具有更大的相对丰度，在 DS 下，放线菌门 (Actinobacteriota) (16.1%) 具有最高的相对丰度。与其他两种胁迫处理相比，当暴露于 HS 时，担子菌门 (31.2%) 的相对丰度显着升高。代谢物由酚醚、脂肪酰基、有机氧化合物、烯丙基型1,3-偶极有机分子和有机硝基化合物组成，在不同处理中丰度存在差异。通路分析强调了与 DS 或 HS 相比，接触 DHS 时 ABC 转运蛋白、青霉素/头孢菌素生物合成和缬氨酸/亮氨酸/异亮氨酸生物合成途径的上调。总体而言，这些研究结果表明，DHS 会刺激根部分泌 L-缬氨酸，从而促进 Gemmatimonadota 的募集并改善 DHS 下根部对硝酸盐和铵的吸收。简而言之，这些结果提供了对微生物与植物之间相互作用的重要见解，以及利用有益微生物群落提高玉米在不同类型非生物胁迫下的恢复力和生产力的潜力。