Functional analyses of various strigolactone‐deficient mutants have demonstrated that strigolactones enhance drought resistance; however, the mechanistic involvement of the strigolactone receptor DWARF14 (D14) in this trait remains elusive. In this study, loss‐of‐function analysis of the D14 gene in Arabidopsis thaliana revealed that d14 mutant plants were more drought‐susceptible than wild‐type plants, which was associated with their larger stomatal aperture, slower abscisic acid (ABA)‐mediated stomatal closure, lower anthocyanin content and delayed senescence under drought stress. Transcriptome analysis revealed a consistent alteration in the expression levels of many genes related to the observed physiological and biochemical changes in d14 plants when compared with the wild type under normal and dehydration conditions. A comparative drought resistance assay confirmed that D14 plays a less critical role in Arabidopsis drought resistance than its paralog karrikin receptor KARRIKIN INSENSITIVE 2 (KAI2). In‐depth comparative analyses of the single mutants d14 and kai2 and the double mutant d14 kai2 , in relation to various drought resistance‐associated mechanisms, revealed that D14 and KAI2 exhibited a similar effect on stomatal closure. On the other hand, D14 had a lesser role in the maintenance of cell membrane integrity, leaf cuticle structure and ABA‐induced leaf senescence, but a greater role in drought‐induced anthocyanin biosynthesis, than KAI2. Interestingly, a possible additive relationship between D14 and KAI2 could be observed in regulating cell membrane integrity and leaf cuticle development. In addition, our findings also suggest the existence of a complex interaction between the D14 and ABA signaling pathways in the adaptation of Arabidopsis to drought.

中文翻译：

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DWARF14和KARRIKIN INSENSITIVE 2在拟南芥干旱适应中的比较功能分析。

各种对内酯不足的突变体的功能分析表明，内酯增强了抗旱性。然而，Strigolactone受体DWARF14（D14）在该性状中的机制参与仍然难以捉摸。在这项研究中，对拟南芥中D14基因的功能丧失分析表明，d14突变植物比野生型植物更易受干旱影响，这与它们的较大气孔孔径，较慢的脱落酸（ABA）介导有关干旱胁迫下气孔关闭，花青素含量降低和衰老延迟。转录组分析揭示了与观察到的生理和生化变化有关的许多基因表达水平的一致变化。与正常和脱水条件下的野生型相比，d14植物。一项比较抗旱性试验证实，D14在拟南芥抗旱性中的作用不如其旁系同源karrikin受体KARRIKIN INSENSITIVE 2（KAI2）。对单突变体d14和kai2和双突变体d14 kai2的深入比较分析，与各种抗旱相关机制有关，揭示了D14和KAI2对气孔关闭表现出相似的作用。另一方面，与KAI2相比，D14在维持细胞膜完整性，叶片表皮结构和ABA诱导的叶片衰老中的作用较小，但在干旱诱导的花色苷生物合成中的作用较大。有趣的是，在调节细胞膜完整性和叶表皮发育中可以观察到D14和KAI2之间可能存在加性关系。此外，我们的发现还表明在拟南芥对干旱的适应中，D14和ABA信号通路之间存在复杂的相互作用。