ABSTRACT The objective of the study was to understand the evolution characteristics of miR156 gene family and its expression patterns in calyx abscission zone (AZ) tissues of Korla fragrant pear (Pyrus sinkiangensis Yu). miR156 family of Korla fragrant pear (psi-miR156) was obtained through small RNA sequencing. We analysed the mature sequences and precursor sequence, constructed phylogenetic tree, predicted the secondary structure of precursors sequence, analysed their targets, as well as expression patterns. The results showed that miR156 family of Korla fragrant pear comprises 11 precursor sequences and 6 mature sequences. These precursor sequences can form a typical and stable stem-loop structure. Their minimum folding free energy ranges from −77.20 to −7.99 kal•mol−1. Multiple sequence alignment showed that miR156 family was highly conserved. Phylogenetic tree analysis indicated that the genetic relationship of psi-miR156 family was closer to those from apple and Arabidopsis thaliana. Psi-miR156 family was predicted to target SPL (Squamosa promoter-binding protein-like), cysteine protease, trihelix transcription factor. qRT-PCR showed that different members of psi-miR156 family had similar expression tendency in calyx AZ tissue. The expression level of miR156 was significantly increased on the fifth day of the late bloom stage, suggesting that the miR156 family may play a role in calyx persistence of Korla fragrant pear. Abbreviations: AZ: abscission zone; SPL: Squamosa promoter-binding protein-like; PP333: Paclobutrazol; C_1: The collected flowers on the first day of the late bloom stage with GA3 treatment; C_5: The collected flowers on the fifth day of the late bloom stage with GA3 treatment; C_9: The collected flowers on the ninth day of the late bloom stage with GA3 treatment; T_1: The collected flowers on the first day of the late bloom stage with PP333 treatment; T_5: The collected flowers on the fifth day of the late bloom stage with PP333 treatment; T_9: The collected flowers on the ninth day of the late bloom stage with PP333 treatment.

中文翻译：

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库尔勒香梨（Pyrus sinkiangensis Yu）miR156基因家族的进化特征及表达模式

摘要 本研究的目的是了解库尔勒香梨（Pyrus sinkiangensis Yu）的miR156基因家族的进化特征及其在花萼脱落区（AZ）组织中的表达模式。通过小RNA测序获得库尔勒香梨miR156家族(psi-miR156)。我们分析了成熟序列和前体序列，构建了系统发育树，预测了前体序列的二级结构，分析了它们的靶点，以及表达模式。结果表明，库尔勒香梨miR156家族包含11个前体序列和6个成熟序列。这些前体序列可以形成典型且稳定的茎环结构。它们的最小折叠自由能范围从-77.20 到-7.99 kal•mol-1。多序列比对表明miR156家族高度保守。系统进化树分析表明，psi-miR156 家族的亲缘关系更接近于苹果和拟南芥的亲缘关系。预测 Psi-miR156 家族的目标是 SPL（Squamosa 启动子结合蛋白样）、半胱氨酸蛋白酶、三螺旋转录因子。qRT-PCR显示psi-miR156家族的不同成员在花萼AZ组织中具有相似的表达趋势。miR156 的表达水平在晚花期第 5 天显着增加，表明 miR156 家族可能在库尔勒香梨花萼持久中起作用。缩写： AZ：脱落区；SPL：鳞状启动子结合蛋白样；PP333：多效唑；C_1：GA3处理的晚花期第一天采集的花朵；C_5：GA3处理的晚花期第5天采集的花朵；C_9：GA3处理的晚花期第9天采集的花朵；T_1：PP333处理的晚花期第一天采集的花朵；T_5：PP333处理的晚花第5天采集的花朵；T_9：PP333处理的晚花期第9天采集的花朵。