Tillering is an important agronomic trait essential for the yield of Triticum aestivum and the propagation of Aegilops tauschii. However, the effect of phytohormones on T. aestivum and Ae. tauschii tillering and the underlying regulatory mechanisms remain poorly understood. In the study, we found that T. aestivum and Ae. tauschii exhibited different tillering sensitivities to the auxin herbicide 2,4-D isooctyl ester. At 3 days post-application, tiller bud growth was inhibited by 79.13% in T. aestivum, corresponding to 2.10-fold greater inhibition than that in Ae. tauschii (37.71%). Transcriptome analysis showed that differentially expressed genes (DEGs) in the T. aestivum response to 2,4-D isooctyl ester were mainly enriched in plant hormone metabolism and signal transduction pathways, but similar changes were not observed in Ae. tauschii. A total of nine candidate genes involved in varied tillering responses were selected from the DEGs and validated by quantitative real-time PCR. Endogenous hormone levels were assayed to further verify the RNA-seq results. After 2,4-D isooctyl ester treatment, a significant increase in abscisic acid (ABA) levels was observed in T. aestivum, whereas ABA levels were relatively stable in Ae. tauschii. The herbicide induced more cytokinin (CTK) accumulation in Ae. tauschii than in T. aestivum. External ABA clearly restricted tiller bud growth in both T. aestivum and Ae. tauschii, while 6-benzyl aminopurine had no significant effect. These results indicate that ABA and CTK participate in 2,4-D isooctyl ester-regulated tillering differences between the two species, which will help to further understand the mechanism of the auxin-mediated regulation of tillering.

中文翻译：

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2,4-D异辛基酯对小麦和小麦节节草分er和内源性植物激素反应的调节

分iller是重要的农艺性状，对于小麦的产量和节节麦草的繁殖必不可少。但是，植物激素对普通小麦（T. aestivum）和大叶黄杨（Ae）的影响。tauschii分er和潜在的调控机制仍然知之甚少。在研究中，我们发现了普通小麦和ae。tauschii对生长素除草剂2,4-D异辛酯的分till敏感性不同。施用后3天，小麦中的分till芽生长被抑制了79.13％，比Ae中的抑制作用大2.10倍。陶西（37.71％）。转录组分析表明，在小麦中对2，4-D异辛酯的反应中的差异表达基因（DEGs）主要富含植物激素代谢和信号转导途径，但在Ae中未观察到类似的变化。陶希 从DEGs中总共选择了9个参与不同分till反应的候选基因，并通过实时定量PCR进行了验证。分析内源激素水平以进一步验证RNA-seq结果。在2,4-D异辛酯处理后，在小麦中观察到脱落酸（ABA）的水平显着增加，而在Ae中ABA的水平则相对稳定。陶希 除草剂在Ae中诱导更多的细胞分裂素（CTK）积累。tauschii比普通小麦。外部ABA明显限制了普通小麦和Ae的分growth芽的生长。tauschii，而6-苄基氨基嘌呤则无明显作用。这些结果表明，ABA和CTK参与了两个物种之间2,4-D异辛酯调节的分till差异，