McLaughlin Heather Marie, Lü Tian-Feng, Natarajan Bhavani, Østergaard Lars, Dong Yang
Department of Crop Genetics, The John Innes Centre, Norwich Research Park, Colney Lane, Norwich NR4 7UH, UK.
Sainsbury Laboratory at Cambridge University, 47 Bateman Street, Cambridge CB2 1LR, UK.
Development. 2025 Feb 1;152(3). doi: 10.1242/dev.204263. Epub 2025 Feb 12.
Gynoecium patterning is dependent on the dynamic distribution of auxin, the signalling of which is transduced through several distinct pathways. ETTIN (ETT)-mediated signalling occurs independently of the canonical auxin pathway, and ETT shares partial redundancy with Auxin Response Factor 4 (ARF4) in the gynoecium. ETT and ARF4 were previously hypothesized to translate auxin gradients into patterns of tissue polarity alongside other ARFs. As ARF repressors, ETT/ARF were assumed to antagonistically regulate targets shared with ARF activators of the canonical pathway. Here, comparative transcriptomics identified the distinct and overlapping targets of ETT/ARF4 in the Arabidopsis gynoecium. However, ETT/ARF4 targets with known roles in gynoecium development did not conform to models of A-B ARF antagonism, leaving the relationship with the canonical pathway unclear. Mutants in tir1 afb2 ett were therefore generated in Arabidopsis and Capsella to assess the relationship between the two pathways, and their conservation in species with distinct fruit shapes. The data presented indicate conserved synergism between the two pathways in gynoecium development and suggest a role for ARF4 in the integration of these pathways in Brassicaceae with distinct fruit shapes.
雌蕊模式形成依赖于生长素的动态分布，其信号通过几种不同的途径进行转导。ETTIN（ETT）介导的信号传导独立于经典生长素途径发生，并且ETT在雌蕊中与生长素响应因子4（ARF4）存在部分冗余。ETT和ARF4先前被假设与其他ARF一起将生长素梯度转化为组织极性模式。作为ARF阻遏物，ETT/ARF被认为与经典途径的ARF激活剂拮抗调节共同的靶标。在这里，比较转录组学确定了拟南芥雌蕊中ETT/ARF4的不同和重叠靶标。然而，在雌蕊发育中具有已知作用的ETT/ARF4靶标不符合A-B ARF拮抗模型，使得与经典途径的关系尚不清楚。因此，在拟南芥和荠中产生了tir1 afb2 ett突变体，以评估这两种途径之间的关系，以及它们在具有不同果实形状的物种中的保守性。所呈现的数据表明这两种途径在雌蕊发育中存在保守的协同作用，并表明ARF4在具有不同果实形状的十字花科植物中整合这些途径中发挥作用。
