Reddy Vaishnavi Amarr, Saju Jolly Madathiparambil, Nadimuthu Kumar, Sarojam Rajani
Temasek Life Sciences Laboratory, National University of Singapore, Singapore, Singapore.
Front Plant Sci. 2024 Feb 5;15:1284125. doi: 10.3389/fpls.2024.1284125. eCollection 2024.
Phytohormone auxin controls various aspects of plant growth and development. The typical auxin signalling involves the degradation of canonical Aux/IAA proteins upon auxin perception releasing the auxin response factors (ARF) to activate auxin-regulated gene expression. Extensive research has been pursued in deciphering the role of canonical Aux/IAAs, however, the function of non-canonical genes remains elusive. Here we identified a non-canonical gene, from spearmint (), which lacks the TIR1-binding domain and shows its involvement in the development of peltate glandular trichomes (PGT), which are the sites for production and storage of commercially important essential oils. Using yeast two-hybrid studies, two canonical Aux/IAAs, MsIAA3, MsIAA4 and an ARF, MsARF3 were identified as the preferred binding partners of MsIAA32. Expression of a R2R3-MYB gene and a cyclin gene was altered in suppressed plants indicating that these genes are possible downstream targets of MsIAA32 mediated signalling. Ectopic expression of in affected non-glandular trichome formation along with other auxin related developmental traits. Our findings establish the role of non-canonical Aux/IAA mediated auxin signalling in PGT development and reveal species-specific functionalization of Aux/IAAs.
植物激素生长素控制植物生长和发育的各个方面。典型的生长素信号传导涉及在生长素感知后经典Aux/IAA蛋白的降解，从而释放生长素反应因子（ARF）以激活生长素调节的基因表达。人们对解析经典Aux/IAA的作用进行了广泛研究，然而，非经典基因的功能仍然难以捉摸。在这里，我们从留兰香中鉴定出一个非经典基因，它缺乏TIR1结合结构域，并显示其参与盾状腺毛（PGT）的发育，盾状腺毛是商业上重要的精油生产和储存部位。通过酵母双杂交研究，两个经典Aux/IAA，MsIAA3、MsIAA4和一个ARF，MsARF3被鉴定为MsIAA32的首选结合伙伴。在MsIAA32抑制的植物中，一个R2R3-MYB基因和一个细胞周期蛋白基因的表达发生了改变，表明这些基因可能是MsIAA32介导的信号传导的下游靶标。MsIAA32在拟南芥中的异位表达影响了非腺毛的形成以及其他与生长素相关的发育性状。我们的研究结果确立了非经典Aux/IAA介导的生长素信号传导在盾状腺毛发育中的作用，并揭示了Aux/IAA的物种特异性功能化。
