Qian Jingjing, Wang Ning, Ren Wenxu, Zhang Rufan, Hong Xiyao, Chen Lingyue, Zhang Kaijing, Shu Yingjie, Hu Nengbing, Yang Yuchen
College of Agriculture, Anhui Science and Technology University, Fengyang, China.
State Key Laboratory of Biocontrol, School of Ecology, Sun Yat-sen University, Guangzhou, China.
Front Plant Sci. 2022 Mar 10;13:866193. doi: 10.3389/fpls.2022.866193. eCollection 2022.
Dwarfed stature is a desired trait for modern orchard production systems. One effective strategy for dwarfing cultivation is exogenously applying plant growth retardants (PGRs) to plants. However, for many economic fruit trees, the current knowledge on the regulatory mechanisms underlying the dwarfing effect of PGRs is limited, which largely restricts the agricultural application of PGRs. In this study, we exogenously applied three kinds of PGRs [paclobutrazol, daminozide (B9), and mannitol] to the seedlings of pomegranate ( L.) and performed comparative transcriptome analysis to elucidate the molecular features of PGR-induced dwarfing in pomegranates. Our results showed that all the three PGRs could significantly suppress plant growth of pomegranate. The inhibition of auxin biosynthetic processes, as well as auxin-mediated shoot development, may be considered as the main reason for the dwarfing. Besides that, different PGRs were also found to induce dwarfing specific mechanisms, for example, cellular response to strigolactone was particularly suppressed by the application of paclobutrazol, while the level of carbohydrate homeostasis and metabolism were downregulated in conditions of either B9 or mannitol treatments. Furthermore, exogenous PGR application was supposed to cause adverse impacts on the normal physiological process of pomegranate seedlings, which may bring extra burden to pomegranate plants. These novel findings unveiled the genetic basis underlying the dwarfing in pomegranates, which provides deeper insights into PGR-mediated dwarfing cultivation of pomegranates.
矮小的树高是现代果园生产系统所期望的性状。矮化栽培的一种有效策略是向植物外源施用植物生长延缓剂（PGR）。然而，对于许多经济果树来说，目前关于PGR矮化效应潜在调控机制的知识有限，这在很大程度上限制了PGR在农业上的应用。在本研究中，我们向石榴（L.）幼苗外源施用了三种PGR[多效唑、二甲基氨基琥珀酰胺酸（B9）和甘露醇]，并进行了比较转录组分析，以阐明PGR诱导石榴矮化的分子特征。我们的结果表明，所有这三种PGR都能显著抑制石榴的植株生长。生长素生物合成过程以及生长素介导的枝条发育受到抑制，可能被认为是矮化的主要原因。除此之外，还发现不同的PGR诱导矮化的特定机制，例如，多效唑的施用特别抑制了对独脚金内酯的细胞反应，而在B9或甘露醇处理条件下，碳水化合物稳态和代谢水平下调。此外，外源施用PGR可能会对石榴幼苗的正常生理过程产生不利影响，这可能会给石榴植株带来额外负担。这些新发现揭示了石榴矮化的遗传基础，为PGR介导的石榴矮化栽培提供了更深入的见解。
