title: The root cortex cell hydraulic conductivity is enhanced with increasing chromosome ploidy in wheat.
abstract: Wheat (Triticum spp.) root water uptake is enhanced with increasing chromosome ploidy, but the underlying mechanism is unclear. The leaf transpiration rate (E), individual root (Lp(r)) and cortical cell (Lp(c)) hydraulic conductivity, cortical cell volume (V(c)) and transcription levels of two putative plasma intrinsic aquaporin genes (PIPs) were investigated in wheat seedlings with different chromosome ploidy (Triticum monococcum (2X, AA); Triticum dicoccum (4X, BB); Triticum aestivum (6X, AABBDD)). The E, Lp(r) and Lp(c) of wheat increased with increasing ploidy, but the Vc was reduced. Osmotic stress significantly reduced the E, Lp(c), Lp(r), and the relative mRNA content of TaPIP1;2 and TaPIP2;5 in wheat. Under both well-watered and osmotic stress conditions, the Lp(r) was significantly and positively correlated with the E and Lp(c), and the relative mRNA content of TaPIP1;2 and TaPIP2;5 was significantly and positively correlated with Lp(c) and Lp(r), respectively. For well-watered or osmotically stressed wheat plants, the Lp(c) was reduced, but the L(p)(c)/Lp(r) increased with increasing V(c), suggesting that Vc affects root radical water transport. Thus, the increased Lp(c) and transcription levels of TaPIP1;2 and TaPIP2;5 in wheat roots provides insight into the mechanisms underlying enhanced root water uptake with increasing chromosome ploidy during wheat evolution.
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi 712100, PR China.
authors.forename: Weifeng
authors.initials: W
authors.lastname: Wang
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Yang
authors.forename: Suiqi
authors.initials: S
authors.lastname: Zhang
authors.forename: Yingying
authors.initials: Y
authors.lastname: Sun
mesh_terms: D020346:Aquaporins / Q000235:genetics*; D018506:Gene Expression Regulation, Plant; D009997:Osmotic Pressure; D018515:Plant Leaves / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics; D018517:Plant Roots / Q000033:anatomy & histology / Q000166:cytology* / Q000502:physiology*; D011003:Ploidies; D014908:Triticum / Q000235:genetics*; D014867:Water / Q000378:metabolism
chemical_list: D020346:Aquaporins; D010940:Plant Proteins; D014867:Water