Beijing Key Laboratory of Ornamental Plants Germplasm Innovation & Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education and College of Landscape Architecture, Beijing Forestry University, Beijing 100083, China.
Development Center of Science and Technology, Ministry of Agriculture and Rural Affairs, Beijing 100083, China.
Int J Mol Sci. 2018 Jun 22;19(7):1840. doi: 10.3390/ijms19071840.
Heteromorphic self-incompatibility (SI) is an important system for preventing inbreeding in the genus . However, investigations into the molecular mechanisms of SI are lacking. To explore the mechanisms of SI in , the pollen germination and fruiting rates of self- and cross-pollinations between pin and thrum morphs were investigated, and transcriptomics analyses of the pistils after pollination were performed to assess gene expression patterns in pin and thrum SI. The results indicated that exhibits strong SI and that the mechanisms of pollen tube inhibition differ between pin and thrum morphs. While self-pollen tubes of the pin morph were able to occasionally, though rarely, enter the style, those of the thrum morph were never observed to enter the style. The transcriptomics analysis of the pistils revealed 1311 and 1048 differentially expressed genes (DEGs) that were identified by comparing pin self-pollination (PS) vs. pin cross-pollination (PT) and thrum self-pollination (TS) vs. thrum cross-pollination (TP). Notably, about 90% of these DEGs exhibited different expression patterns in the two comparisons. Moreover, pin and thrum DEGs were associated with different Gene Ontology (GO) categories and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways following enrichment analyses. Based on our results, the molecular mechanisms underlying the pin and thrum SI in appear to be distinct. Furthermore, the genes involved in the SI processes are commonly associated with carbohydrate metabolism and environmental adaptation. These results provide new insight into the molecular mechanisms of SI.
异型自交不亲和（SI）是防止属内近交的重要系统。然而，异型 SI 的分子机制研究还很缺乏。为了探索异型 SI 的机制，我们研究了长柱头和短柱头型之间自交和杂交的花粉萌发率和结实率，并对授粉后雌蕊进行转录组分析，以评估长柱头和短柱头 SI 中的基因表达模式。结果表明，表现出强烈的 SI，并且花粉管抑制的机制在长柱头和短柱头型之间不同。虽然长柱头型的自花粉管偶尔能够但很少进入花柱，但短柱头型的花粉管从未观察到进入花柱。雌蕊的转录组分析显示，通过比较长柱头自交（PS）与长柱头杂交（PT）以及短柱头自交（TS）与短柱头杂交（TP），分别鉴定出 1311 和 1048 个差异表达基因（DEGs）。值得注意的是，这些 DEGs 中约 90%在这两个比较中表现出不同的表达模式。此外，长柱头和短柱头 DEGs 经富集分析后与不同的基因本体论（GO）类别和京都基因与基因组百科全书（KEGG）途径相关。基于我们的结果，长柱头和短柱头在异型 SI 中的分子机制似乎不同。此外，参与 SI 过程的基因通常与碳水化合物代谢和环境适应有关。这些结果为异型 SI 的分子机制提供了新的见解。
