Potato (Solanum tuberosum L.) is one of the most important food crops globally and is especially vulnerable to heat stress. However, substantial knowledge gaps remain in our understanding of the developmental mechanisms associated with tuber responses to heat stress. This study used whole-plant physiology, transcriptomics, and phytohormone profiling to elucidate how heat stress affects potato tuber development. When plants were grown in projected future elevated temperature conditions, abscisic acid (ABA) levels decreased in leaf and tuber tissues, whereas rates of leaf carbon assimilation and stomatal conductance were not significantly affected compared to those plants grown in historical temperature conditions. While plants grown in projected future elevated temperature conditions initiated more tubers per plant on average, there was a 66% decrease in mature tubers at final harvest compared to those plants grown in historical temperature conditions. We hypothesize that reduced tuber yields at elevated temperatures are not due to reduced tuber initiation, but due to impaired tuber filling. Transcriptomic analysis detected significant changes in the expression of genes related to ABA response, heat stress and starch biosynthesis. The tuberization repressor genes SELF PRUNING 5G (StSP5G) and CONSTANS-LIKE1 (StCOL1) were differentially expressed in tubers grown in elevated temperatures. Two additional known tuberization genes, IDENTITY OF TUBER 1 (StIT1) and TIMING OF CAB EXPRESSION 1 (StTOC1), displayed distinct expression patterns under elevated temperatures compared to historical temperature conditions but were not differentially expressed. This work highlights potential gene targets and key developmental stages associated with tuberization to develop potatoes with greater heat tolerance.

中文翻译：

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马铃薯块茎化对预计未来高温的生理和分子响应


马铃薯 （Solanum tuberosum L.） 是全球最重要的粮食作物之一，特别容易受到热应激的影响。然而，我们对与块茎对热应激反应相关的发育机制的理解仍然存在很大的知识差距。本研究使用全植物生理学、转录组学和植物激素分析来阐明热应激如何影响马铃薯块茎发育。当植物在预计的未来高温条件下生长时，叶片和块茎组织中的脱落酸 （ABA） 水平降低，而与在历史温度条件下生长的植物相比，叶片碳同化速率和气孔导度没有受到显著影响。虽然在预计的未来高温条件下生长的植物平均每株产生更多的块茎，但与在历史温度条件下生长的植物相比，最终收获时成熟块茎减少了 66%。我们假设高温下块茎产量降低不是由于块茎启动减少，而是由于块茎填充受损。转录组学分析检测到与 ABA 反应、热应激和淀粉生物合成相关的基因表达的显着变化。结节化抑制基因 SELF PRUNING 5G （StSP5G） 和 CONSTANS-LIKE1 （StCOL1） 在高温生长的块茎中差异表达。另外两个已知的结核基因，IDENTITY OF TUBER 1 （StIT1） 和 TIMING OF CAB EXPRESSION 1 （StTOC1），与历史温度条件相比，在高温下表现出不同的表达模式，但没有差异表达。 这项工作强调了与块茎化相关的潜在基因靶点和关键发育阶段，以开发出具有更高耐热性的马铃薯。