In flowering plants, the pollen coat protects the released male germ cells from desiccation and damage during pollination. However, we know little about the mechanism by which the chemical composition of the pollen coat prevents dehydration of pollen grains. Here we report that deficiency of a grass conserved triterpene synthase, OsOSC12/OsPTS1, in rice leads to failure of pollen coat formation. The mutant plants are male sterile at low relative humidity (RH < 60%), but fully male fertile at high relative humidity (>80%). The lack of three major fatty acids in the pollen coat results in rapid dehydration of pollen grains. We show that applying mixtures of linolenic acid and palmitic acid or stearic acid are able to prevent over-dehydration of mutant pollen grains. We propose that humidity-sensitive genic male sterility (HGMS) could be a desirable trait for hybrid breeding in rice, wheat, maize, and other crops.
開花植物中，花粉包被在授粉過程中保護(hù)釋放的精細(xì)胞免受脫水和破壞。然而，我們對防止花粉粒脫水的包被化學(xué)成分知之甚少。本文，我們報(bào)道了一種禾本科植物中保守的三萜合酶OsOSC12/OsPTS1，它的缺乏導(dǎo)致水稻花粉包被形成失敗。突變體植株在相對低濕度（RH < 60%）下雄性不育，但在相對高濕度（>80%）下雄性完全可育?；ǚ郯蝗鄙偃N主要脂肪酸，導(dǎo)致花粉粒迅速脫水。我們發(fā)現(xiàn)外施亞麻酸和棕櫚酸或硬脂酸的混合物可以防止花粉突變體的過度脫水。我們認(rèn)為，濕敏雄性核不育（HGMS）可能是水稻、小麥、玉米和其他作物雜交育種的理想性狀。