Moran Lauter Adrienne N, Muszynski Michael G, Huffman Ryan D, Scott M Paul
Corn Insects and Crop Genetics Research Unit, USDA-ARS, Ames, IA, United States.
Department of Tropical Plant and Soil Sciences, University of Hawaii at Manoa, Honolulu, HI, United States.
Front Plant Sci. 2017 Nov 7;8:1926. doi: 10.3389/fpls.2017.01926. eCollection 2017.
The locus of maize confers unilateral cross incompatibility, preventing cross pollination between females carrying the incompatible allele and males not carrying a corresponding compatible allele. To characterize this system at the molecular level, we carried out a transcript profiling experiment in which silks from near isogenic lines carrying the and alleles were compared. While several differentially expressed genes were identified, only one mapped to the known location of . This gene is a pectin methylesterase (PME), which we designated as , and is present and expressed only in - genotypes. While a functional ZmPME3 is not present in the genotypes examined, a pectin methylesterase gene cluster is found in genotypes. The gene cluster in W22 contains 58 tandem full-length or partial PME pseudo genes. These data combined with a wealth of previously published data on the involvement of PMEs in pollen tube growth suggest a role for cell wall modification enzymes in the pollen exclusion component of gametophytic incompatibility. Consistent with this role, a third allele which lacks the female function of , has a mutationally inactivated version of .
玉米的该位点赋予单侧杂交不亲和性，阻止携带不亲和等位基因的雌株与不携带相应亲和等位基因的雄株之间的异花授粉。为了在分子水平上表征该系统，我们进行了一项转录谱分析实验，比较了携带和等位基因的近等基因系的花丝。虽然鉴定出了几个差异表达基因，但只有一个映射到已知的位点位置。该基因是一种果胶甲酯酶（PME），我们将其命名为，并且仅在基因型中存在并表达。在所检测的基因型中不存在功能性ZmPME3，但在基因型中发现了一个果胶甲酯酶基因簇。W22中的基因簇包含58个串联的全长或部分PME假基因。这些数据与先前发表的大量关于PME参与花粉管生长的数据相结合，表明细胞壁修饰酶在配子体不亲和性的花粉排斥成分中起作用。与此作用一致，第三个缺乏雌性功能的等位基因具有一个发生突变失活的版本。
