为在基因水平上探究薄壳山核桃〔Carya illinoinensis (Wangenh.) K. Koch〕果实迅速膨大期乙烯调控幼果脱落的机制，以薄壳山核桃主栽品种‘波尼’（‘Pawnee’）为研究对象，在差异表达基因分析、关键理化和生长指标比较、序列同源性比对、系统发育树分析、基因表达分析、蛋白亚细胞定位和蛋白互作等方面进行研究。结果表明：与正常发育幼果相比，即将脱落幼果（发育缓慢的幼果）中CiMAPK3、CiACS6、CiACOs及乙烯信号转导相关基因的表达量均显著（P＜0.05）升高，1-氨基环丙烷-1-羧酸（ACC）含量及ACC合成酶（ACS）活性显著升高。总体来看，与对照组（蒸馏水）相比，250 mg·L^-1乙烯利处理组的落果率显著升高，单果质量显著降低，CiMAPK3的相对表达量在0.01水平显著升高，CiACS6和CiETR2的相对表达量在0.000 1水平显著升高。序列同源性比对和系统发育树分析结果均表明克隆得到的序列为CiMAPK3和CiACS6基因序列。亚细胞定位结果显示CiMAPK3和CiACS6定位于细胞核和细胞膜。蛋白互作结果显示CiMAPK3和CiACS6间不存在互作关系。综上所述，乙烯能够促使薄壳山核桃果实迅速膨大期幼果脱落，CiMAPK3可能间接调控CiACS6的表达，促进乙烯生物合成，从而诱导幼果脱落。

To investigate the mechanism of ethylene regulates nutlet abscission of Carya illinoinensis (Wangenh.) K. Koch during the rapid nut sizing stage at the gene level, the main cultivar ‘Pawnee’ of C. illinoinensis was used as the research subject. The study was conducted on   differentially expressed gene analysis,   key physicochemical and growth index comparisons, sequence homology alignment, phylogenic tree analysis, gene expression analysis, protein subcellular localization, protein interaction, etc. The results show that compared with the persisting nutlets, the expression levels of CiMAPK3, CiACS6, CiACOs, and ethylene signal transduction related genes are significantly (P＜0.05) increased in abscising nutlets (slow-growing nutlets), and 1-aminocyclopropane-1-carboxylic acid (ACC) content and ACC synthase (ACS) activity are significantly increased in abscising nutlets. Overall, compared with the control group (distilled water), the nutlet abscission rate in the 250 mg·L^-1 ethephon treatment group is significantly increased, the single nutlet mass is significantly decreased, the relative expression of CiMAPK3 is significantly increased at 0.01 level, and the relative expressions of CiACS6 and CiETR2 are significantly increased at 0.000 1 level. Both sequence homology alignment and phylogenic tree analysis results show that the cloned sequences are the sequences of CiMAPK3 and CiACS6 genes. Subcellular localization results indicate that CiMAPK3 and CiACS6 are localized in the nucleus and cell membrane. Protein interaction results indicate that there is no interaction between CiMAPK3 and CiACS6. In summary, ethylene can promote the nutlet abscission of C. illinoinensis during the rapid nut sizing stage. CiMAPK3 maybe indirectly regulates the expression of CiACS6, enhances ethylene biosynthesis, thereby induces the nutlet abscission.