Photoperiod- and thermosensitive genic male sterility (P/TGMS) lines are widely used in crop breeding. The fertility conversion of Arabidopsis (Arabidopsis thaliana) TGMS lines including cals5-2, which is defective in callose wall formation, relies on slow development under low temperatures. In this study, we discovered that cals5-2 also exhibits PGMS. Fertility of cals5-2 was restored when pollen development was slowed under short-day photoperiods or low light intensity, suggesting that slow development restores the fertility of cals5-2 under these conditions. We found that several other TGMS lines with defects in pollen wall formation also exhibited PGMS characteristics. This similarity indicates that slow development is a general mechanism of PGMS fertility restoration. Notably, slow development also underlies the fertility recovery of TGMS lines. Further analysis revealed the pollen wall features during the formation of functional pollens of these P/TGMS lines under permissive conditions. We conclude that slow development is a general mechanism for fertility restoration of P/TGMS lines and allows these plants to take different strategies to overcome pollen formation defects.

光周期和热敏基因雄性不育（P/TGMS）品系广泛应用于作物育种。包括胼胝质壁形成缺陷的cals5-2在内的拟南芥TGMS品系的育性转化依赖于低温下的缓慢发育。在这项研究中，我们发现cals5-2也表现出 PGMS。当花粉发育在短日照周期或低光强度下减慢时，cals5-2的育性得以恢复，这表明在这些条件下缓慢的发育恢复了cals5-2的育性。我们发现其他几个花粉壁形成缺陷的 TGMS 品系也表现出 PGMS 特征。这种相似性表明发育缓慢是 PGMS 生育能力恢复的一般机制。值得注意的是，缓慢的发育也是 TGMS 系生育力恢复的基础。进一步的分析揭示了这些 P/TGMS 品系在允许条件下形成功能性花粉过程中的花粉壁特征。我们得出结论，缓慢发育是 P/TGMS 品系育性恢复的一般机制，并允许这些植物采取不同的策略来克服花粉形成缺陷。