To understand the molecular and physiological mechanism underlying the heat stress in maize, transcriptional and physiological response to heat stress in the heat-resistant Huangzaosi (HZS) and heat-sensitive Lv-9-Kuan (L9K) inbred lines at seedling stage were analyzed and compared at seedling stage. Our results indicated that MDA content of the two inbred lines increased significantly under heat stress; the values of MDA in L9K was significantly higher than that in HZS. The level of SOD, CAT, and POD enzyme activities in HZS was higher than those in L9K for both the heat-treated group and controls. The values of Fv/Fm, qP, and ФPSII reduced by heat stress in L9K were higher than the respective values in HZS. RNA-seq data showed that heat stress induced more heat stress-related genes in HZS (257 heat stress-related genes) than in L9K (224 heat stress-related genes). GO and KEGG enrichment analyses indicated that HZS and L9K changed their physiological and biochemical mechanisms in response to heat stress through different molecular mechanisms. Weighted Gene Co-expression Network Analysis showed that HZS might obtain stronger heat resistance than L9K through a unique transcriptional regulatory network. Our findings provide insights into the molecular networks that mediate the tolerance of maize heat stress and also help us to mine key heat stress-related genes.

中文翻译：

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耐热热敏玉米（Zea mays L.）自交系幼苗期对热胁迫的生理和转录反应

为了解玉米热胁迫的分子和生理机制，分析了耐热黄枣斯（HZS）和热敏Lv-9-宽（L9K）自交系苗期对热胁迫的转录和生理反应。苗期比较。我们的结果表明，在热胁迫下，两个自交系的MDA含量显着增加；L9K的MDA值明显高于HZS。热处理组和对照组的 HZS 中 SOD、CAT 和 POD 酶活性水平均高于 L9K。L9K热应激降低的Fv/Fm、qP和ФPSII值均高于HZS。RNA-seq数据显示，与L9K（224个热应激相关基因）相比，热应激在HZS（257个热应激相关基因）中诱导了更多的热应激相关基因。GO和KEGG富集分析表明，HZS和L9K通过不同的分子机制改变了响应热应激的生理生化机制。加权基因共表达网络分析表明，HZS 可能通过独特的转录调控网络获得比 L9K 更强的耐热性。我们的研究结果提供了对介导玉米热应激耐受性的分子网络的见解，也有助于我们挖掘关键的热应激相关基因。GO和KEGG富集分析表明，HZS和L9K通过不同的分子机制改变了响应热应激的生理生化机制。加权基因共表达网络分析表明，HZS 可能通过独特的转录调控网络获得比 L9K 更强的耐热性。我们的研究结果提供了对介导玉米热应激耐受性的分子网络的见解，也有助于我们挖掘关键的热应激相关基因。GO和KEGG富集分析表明，HZS和L9K通过不同的分子机制改变了响应热应激的生理生化机制。加权基因共表达网络分析表明，HZS 可能通过独特的转录调控网络获得比 L9K 更强的耐热性。我们的研究结果提供了对介导玉米热应激耐受性的分子网络的见解，也有助于我们挖掘关键的热应激相关基因。