Abstract Heat stress (HS) is a major problem of tomato production worldwide, as it reduces fruit setting due to the adverse effects on pollen development and fertility. In this study, we isolated heat-tolerant (HT) mutants providing improved fruit-setting under long-term ambient high temperature by testing over 4000 lines from the Micro-Tom tomato mutant collection. The HT mutants were categorized into two types, namely those that produced parthenocarpic fruit, and those that produced fruit with seeds. Among the HT mutants, HT7 plants produced fruit with seeds, had a higher fruit number and seeded-fruit yield, and the total pollen number and viability were much higher under HS conditions than those of the WT under both control and HS conditions. HT7 also succeeded at fertilization even under HS conditions due to higher pollen viability than the WT. In addition, HS-related genes, such as SIHsfA1b3 and Hsp101, were more highly expressed in HT7 than in WT. These results suggest that HT7 could be a valuable genetic resource for elucidating heat tolerance mechanisms and a breeding material for improving heat-tolerant fruit-setting in tomato.

中文翻译：

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番茄耐热突变体在长期环境高温下表现出改善的花粉育性和坐果

摘要 热应激 (HS) 是全球番茄生产的一个主要问题，因为它会因对花粉发育和生育力的不利影响而减少坐果。在这项研究中，我们通过测试来自 Micro-Tom 番茄突变体集合的 4000 多个品系，分离出耐热 (HT) 突变体，这些突变体在长期环境高温下提供了改进的坐果。HT突变体分为两种类型，即产生单性果实的突变体和产生有种子果实的突变体。在HT突变体中，HT7植株结实结实，果实数和实果产量更高，HS条件下的总花粉数和活力远高于对照和HS条件下的WT。由于花粉活力高于 WT，HT7 即使在 HS 条件下也能成功受精。此外，HS 相关基因，如 SIHsfA1b3 和 Hsp101，在 HT7 中的表达比在 WT 中更高。这些结果表明 HT7 可能是阐明耐热机制的宝贵遗传资源和改善番茄耐热坐果的育种材料。