Propagation mode shapes contrasting growth strategies through aquaporin networks in onion

Abstract

Propagation mode strongly influences crop establishment, yet its impact on whole-plant transport strategies remains poorly understood. Here, we examined whether seed- and set-derived plants deploy contrasting aquaporin networks associated with different physiological behaviours in onion (Allium cepa L.). We combined genome-wide gene-family characterisation with transcriptomic, biochemical, and physiological analyses. Forty-eight aquaporin genes were identified and classified into four subfamilies (15 PIPs, 19 TIPs, 8 NIPs, and 6 SIPs), with evidence of lineage-specific expansion in the PIP1 and TIP2. Expression analyses revealed clear propagation-dependent patterns. Set-derived plants displayed higher expression of AcPIP1.1, several PIP2 isoforms and most TIP2 members in both roots and leaves, consistent with enhanced water and CO2 transport, higher stomatal conductance, transpiration, and photosynthetic rates. In contrast, seed-derived plants showed increased expression of specific PIPs, and several NIPs (AcNIP1.1, AcNIP3.1, AcNIP5.1, AcNIP5.2, and AcNIP2.1) associated with solute and H2O2 transport, coinciding with higher boron and hydrogen peroxide levels. These findings indicate that propagation origin is associated with alternative aquaporin-mediated transport strategies: set-derived plants favour a high-flux strategy that supports rapid growth, whereas seed-derived plants prioritize tighter internal regulation through solute redistribution and redox homeostasis. Our results provide a molecular-physiological framework linking propagation origin with resource-use strategies in onion. HighlightPropagation origin reprograms aquaporin expression in onion, generating contrasting hydraulic, metabolic and growth strategies. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=80 SRC="FIGDIR/small/728701v1_ufig1.gif" ALT="Figure 1"> View larger version (41K): org.highwire.dtl.DTLVardef@b07bc1org.highwire.dtl.DTLVardef@8cda01org.highwire.dtl.DTLVardef@13c843eorg.highwire.dtl.DTLVardef@e26fb_HPS_FORMAT_FIGEXP M_FIG C_FIG