State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 100101, Beijing, China.
University of Chinese Academy of Sciences, 100039, Beijing, China.
Nat Commun. 2018 Sep 10;9(1):3678. doi: 10.1038/s41467-018-06139-8.
Unilateral cross-incompatibility (UCI) is a unidirectional inter/intra-population reproductive barrier when both parents are self-compatible. Maize Gametophyte factor1 (Ga1) is an intraspecific UCI system and has been utilized in breeding. However, the mechanism underlying maize UCI specificity has remained mysterious for decades. Here, we report the cloning of ZmGa1P, a pollen-expressed PECTIN METHYLESTERASE (PME) gene at the Ga1 locus that can confer the male function in the maize UCI system. Homozygous transgenic plants expressing ZmGa1P in a ga1 background can fertilize Ga1-S plants and can be fertilized by pollen of ga1 plants. ZmGa1P protein is predominantly localized to the apex of growing pollen tubes and may interact with another pollen-specific PME protein, ZmPME10-1, to maintain the state of pectin methylesterification required for pollen tube growth in Ga1-S silks. Our study discloses a PME-mediated UCI mechanism and provides a tool to manipulate hybrid breeding.
单侧不亲和性（UCI）是指当双亲均为自交亲和时，发生的单向种间/种内生殖障碍。玉米配子体因子 1（Ga1）是一种种内 UCI 系统，已被用于杂交育种。然而，几十年来，玉米 UCI 特异性的机制一直是个谜。在这里，我们报道了 ZmGa1P 的克隆，这是一个在 Ga1 基因座上表达的花粉质膜酯酶（PME）基因，它可以在玉米 UCI 系统中赋予雄性功能。在 ga1 背景下表达 ZmGa1P 的纯合转基因植物可以使 Ga1-S 植物受精，并且可以被 ga1 植物的花粉受精。ZmGa1P 蛋白主要定位于生长花粉管的顶端，可能与另一个花粉特异性的 PME 蛋白 ZmPME10-1 相互作用，以维持 Ga1-S 花丝中生长所需的果胶甲酯化状态花粉管。我们的研究揭示了一种 PME 介导的 UCI 机制，并提供了一种操纵杂交育种的工具。
