Elevated temperatures impair pollen performance and reproductive success, resulting in lower crop yields. The tomato (Solanum lycopersicum) anthocyanin reduced (are) mutant harbors a mutation in FLAVANONE 3-HYDROXYLASE (F3H), resulting in impaired flavonol antioxidant biosynthesis. The are mutant has reduced pollen performance and seed set relative to the VF36 parental line, phenotypes that are accentuated at elevated temperatures. Transformation of are with the wild-type F3H gene, or chemical complementation with flavonols, prevented temperature-dependent reactive oxygen species (ROS) accumulation in pollen and restored the reduced viability, germination, and tube elongation of are to VF36 levels. Overexpression of F3H in VF36 prevented temperature-driven ROS increases and impaired pollen performance, revealing that flavonol biosynthesis promotes thermotolerance. Although stigmas of are had reduced flavonol and elevated ROS levels, the growth of are pollen tubes was similarly impaired in both are and VF36 pistils. RNA-seq was performed at optimal and stress temperatures in are, VF36, and the F3H overexpression line at multiple timepoints across pollen tube elongation. The number of differentially expressed genes increased over time under elevated temperatures in all genotypes, with the greatest number in are. These findings suggest potential agricultural interventions to combat the negative effects of heat-induced ROS in pollen that lead to reproductive failure.

中文翻译：

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黄酮醇通过维持活性氧稳态来提高番茄花粉发芽和管伸长过程中的耐热性


高温会损害花粉性能和繁殖成功，导致作物产量降低。番茄 （Solanum lycopersicum） 花青素还原 （are） 突变体在黄酮 3-羟化酶 （F3H） 中携带突变，导致黄酮醇抗氧化生物合成受损。相对于 VF36 亲本系，突变体的花粉性能和种子凝固率降低，表型在高温下更加突出。与野生型 F3H 基因的转化，或与黄酮醇的化学互补，阻止了花粉中温度依赖性活性氧 （ROS） 的积累，并将 ARE 的活力降低、发芽和管伸长恢复到 VF36 水平。在 VF36 中过表达 F3H 阻止了温度驱动的 ROS 增加并损害了花粉性能，揭示了黄酮醇生物合成促进耐热性。尽管 are 的柱头具有降低的黄酮醇和 ROS 水平升高，但 are 和 VF36 雌蕊的花粉管生长同样受到损害。在 ARE 、 VF36 和 F3H 过表达系的最佳和应激温度下，在花粉管伸长的多个时间点进行 RNA-seq。在所有基因型中，在高温下，差异表达基因的数量随着时间的推移而增加，其中 are 的数量最多。这些发现表明了潜在的农业干预措施，以对抗花粉中热诱导的 ROS 导致生殖失败的负面影响。