Table1_Comparative stigmatic transcriptomics reveals self and cross pollination responses to heteromorphic incompatibility in Plumbago auriculata Lam..XLS

“Heteromorphic self-incompatibility” (HetSI) in plants is a mechanism of defense to avoid self-pollination and promote outcrossing. However, the molecular mechanism underlying HetSI remains largely unknown. In this study, RNA-seq was conducted to explore the molecular mechanisms underlying self-compatible (SC, “T × P” and “P × T”) and self-incompatible (SI, “T × T” and “P × P”) pollination in the two types of flowers of Plumbago auriculata Lam. which is a representative HetSI plant. By comparing “T × P” vs. “T × T”, 3773 (1407 upregulated and 2366 downregulated) differentially expressed genes (DEGs) were identified, 1261 DEGs between “P × T” and “P × P” (502 upregulated and 759 downregulated). The processes in which these DEGs were significantly enriched were “MAPK (Mitogen-Activated Protein Kinases-plant) signaling pathway”, “plant-pathogen interaction”,“plant hormone signal transduction”, and “pentose and glucuronate interconversion” pathways. Surprisingly, we discovered that under various pollination conditions, multiple notable genes that may be involved in HetSI exhibited distinct regulation. We can infer that the HetSI strategy might be unique in P. auriculata. It was similar to “sporophytic self-incompatibility” (SSI) but the HetSI mechanisms in pin and thrum flowers are diverse. In this study, new hypotheses and inferences were proposed, which can provide a reference for crop production and breeding.

植物中的异型自交不亲和（Heteromorphic self-incompatibility，HetSI）是一种规避自花授粉、促进异交的防御机制。然而，目前学界对异型自交不亲和背后的分子机制仍知之甚少。本研究针对典型异型自交不亲和植物蓝雪花（Plumbago auriculata Lam.）的两种花型，通过RNA测序（RNA-seq）探究其自交亲和（self-compatible，SC，"T × P"与"P × T"组合）与自交不亲和（self-incompatible，SI，"T × T"与"P × P"组合）授粉的分子机制。通过对比"T × P" vs. "T × T"组合，共鉴定得到3773个差异表达基因（differentially expressed genes，DEGs），其中1407个上调表达、2366个下调表达；对比"P × T"与"P × P"组合则鉴定得到1261个差异表达基因，其中502个上调表达、759个下调表达。上述差异表达基因显著富集于丝裂原活化蛋白激酶（Mitogen-Activated Protein Kinases-plant，MAPK）信号通路、植物-病原体互作、植物激素信号转导以及戊糖与葡萄糖醛酸互变通路。值得注意的是，本研究发现，在不同授粉条件下，多个可能参与异型自交不亲和过程的关键基因呈现出差异化表达调控模式。据此我们推测，蓝雪花的异型自交不亲和策略可能具有独特性：其机制虽与孢子体自交不亲和（sporophytic self-incompatibility，SSI）相似，但长花柱型（pin）与短花柱型（thrum）花的异型自交不亲和调控机制存在多样性。本研究提出了全新的假说与推论，可为作物生产与育种工作提供参考依据。