Yu Haiyan, Cui Hailan, Chen Jingchao, Chen Pingping, Ji Meijing, Huang Songtao, Li Xiangju
Key Laboratory of Weed Biology and Management, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
Front Plant Sci. 2021 Apr 28;12:642701. doi: 10.3389/fpls.2021.642701. eCollection 2021.
Tillering is an important agronomic trait essential for the yield of and the propagation of . However, the effect of phytohormones on and tillering and the underlying regulatory mechanisms remain poorly understood. In the study, we found that and exhibited different tillering sensitivities to the auxin herbicide 2,4-D isooctyl ester. At 3 days post-application, tiller bud growth was inhibited by 77.50% in , corresponding to 2.0-fold greater inhibition than that in (38.71%). Transcriptome analysis showed that differentially expressed genes (DEGs) in the 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 . Among that, the auxin biosynthesis and signaling induced by 2,4-D isooctyl ester was quite different between the two species. 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 , whereas ABA levels were relatively stable in . The herbicide induced more cytokinin (CTK) accumulation in than in . External ABA clearly restricted tiller bud growth in both and , while 6-benzyl aminopurine had no significant effect. These results indicate that ABA and CTK may be related with 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.
分蘖是影响[作物名称1]产量和[作物名称2]繁殖的重要农艺性状。然而，植物激素对[作物名称1]和[作物名称2]分蘖的影响及其潜在调控机制仍不清楚。在本研究中，我们发现[作物名称1]和[作物名称2]对生长素类除草剂2,4-二异辛酯表现出不同的分蘖敏感性。施药后3天，[作物名称1]的分蘖芽生长受到77.50%的抑制，比[作物名称2]（38.71%）的抑制程度高2.0倍。转录组分析表明，[作物名称1]对2,4-二异辛酯响应的差异表达基因（DEGs）主要富集在植物激素代谢和信号转导途径中，但在[作物名称2]中未观察到类似变化。其中，2,4-二异辛酯诱导的生长素生物合成和信号传导在两个物种间差异很大。从DEGs中筛选出9个参与不同分蘖反应的候选基因，并通过实时定量PCR进行验证。测定内源激素水平以进一步验证RNA测序结果。2,4-二异辛酯处理后，[作物名称1]中脱落酸（ABA）水平显著升高，而[作物名称2]中ABA水平相对稳定。该除草剂在[作物名称1]中诱导的细胞分裂素（CTK）积累比在[作物名称2]中更多。外源ABA明显抑制了[作物名称1]和[作物名称2]的分蘖芽生长，而6-苄基腺嘌呤没有显著影响。这些结果表明，ABA和CTK可能与2,4-二异辛酯调控的两个物种间分蘖差异有关，这将有助于进一步了解生长素介导的分蘖调控机制。
