miR160a与其靶基因在西瓜嫁接苗中参与抵御低温胁迫

miR160在许多研究中被报道靶向生长素响应因子(ARF)并参与植物的生长发育，但其在葫芦科作物以及嫁接西瓜耐冷性中的调控机制尚不清晰。本研究利用生物信息学技术对miR160a进行了保守性分析、候选靶基因ARF的预测及验证、结合位点分析以及ARF基因家族的进化分析。本文以西瓜(Citrullus lanatus)为接穗材料，分别以印度南瓜(Cucurbita maxima)、中国南瓜(Cucurbita moschata)和美洲南瓜(Cucurbita pepo)作为嫁接的砧木材料，以C6实生苗为对照，通过8^oC低温处理7 d后统计冷害指数，检测不同组织中miR160a和靶基因ARF的表达情况来探究嫁接西瓜miR160a与其靶基因在抵御低温胁迫中的调控作用。结果表明：嫁接显著提高了西瓜植株的抗冷性，影响了miR160a和其ARF靶基因的表达，并且miR160a与其靶基因整体上呈现负向调控的模式来参与嫁接西瓜抵御低温胁迫的过程。本文为今后深入研究嫁接耐冷体系提供了新的参考依据和研究基础。

The Roles of MiR160a and Its Target Genes in Grafted Watermelon Seedlings under Chilling Stress

MiR160 has been reported in many studies to target auxin response factor (ARF) and participate in plant growth and development, while its regulatory mechanism in the chilling resistance of cucurbit plants and grafted watermelon is not clear. In this study, we analyzed the conservation of miR160a, predicted its candidate target gene ARF and analyzed their binding sites, and finally constructed an evolutionary tree of the ARF gene family by bioinformatics techniques. Then watermelon (Citrullus lanatus) was used as the scion material, Indian Pumpkin (Cucurbita maxima), Chinese Pumpkin (Cucurbita moschata), and American Pumpkin (Cucurbita pepo) were grafted as rootstocks. Using C6 seedlings as control, after 7 days of low temperature treatment at 8^oC, the chilling injury indexes were calculated. The expression levels of miR160a and its target gene ARF in different tissues were detected to understand the regulatory role of miR160a and its target genes in resisting low temperature stress in grafted watermelon. The results showed that grafting significantly improved the chilling resistance of watermelon plants and affected the expression of miR160a and its target genes. In addition, miR160a and its target genes showed a negative regulation mode to participate in the process of grafting watermelon to resist low temperature stress. This paper provided a new reference and research basis for the in-depth understanding on the effect of grafting on watermelon chilling tolerance in the future.