In pea (Pisum sativum L.), moderate heat stress during early flowering/fruit set increased seed/ovule abortion, and concomitantly produced fruits with reduced ovary (pericarp) length, and fewer seeds at maturity. Plant hormonal networks coordinate seed and pericarp growth and development. To determine if these hormonal networks are modulated in response to heat stress, we analyzed the gene expression patterns and associated these patterns with precursors, and bioactive and inactive metabolites of the auxin, gibberellin (GA), abscisic acid (ABA), and ethylene biosynthesis/catabolism pathways in young developing seeds and pericarps of non‐stressed and 4‐day heat‐stressed fruits. Our data suggest that within the developing seeds heat stress decreased bioactive GA levels reducing GA growth‐related processes, and that increased ethylene levels may have promoted this inhibitory response. In contrast, heat stress increased auxin biosynthesis gene expression and auxin levels in the seeds and pericarps, and seed ABA levels, both effects can increase seed sink strength. We hypothesize that seeds with higher auxin‐ and ABA‐induced sink strength and adequate bioactive GA levels will set and continue to grow, while the seeds with lower sink strength (low auxin, ABA, and GA levels) will become more sensitive to heat stress‐induced ethylene leading to ovule/seed abortion.

中文翻译：

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平衡激素生物合成和分解代谢途径，改善热应激对生殖生长负面影响的策略


在豌豆（ Pisum sativum L.）中，开花/坐果早期期间的中等热应激会增加种子/胚珠败育，并同时产生子房（果皮）长度缩短和成熟时种子较少的果实。植物激素网络协调种子和果皮的生长和发育。为了确定这些激素网络是否因热应激而受到调节，我们分析了基因表达模式，并将这些模式与生长素、赤霉素 (GA)、脱落酸 (ABA) 和乙烯生物合成的前体以及生物活性和非活性代谢物相关联/非胁迫和 4 天热胁迫水果的年轻发育种子和果皮中的分解代谢途径。我们的数据表明，在发育中的种子中，热应激降低了生物活性 GA 水平，从而减少了 GA 生长相关过程，而乙烯水平的增加可能促进了这种抑制反应。相反，热胁迫增加了种子和果皮中生长素生物合成基因的表达和生长素水平以及种子ABA水平，这两种效应都可以增加种子库强度。我们假设具有较高生长素和 ABA 诱导的库强度和足够的生物活性 GA 水平的种子将固定并继续生长，而具有较低库强度（低生长素、ABA 和 GA 水平）的种子将对热应激变得更加敏感‐诱导乙烯导致胚珠/种子败育。