Characterization of the Heavy-Metal-Associated Isoprenylated Plant Protein (HIPP) Gene Family fromTriticeaeSpecies

Heavy-metal-associated (HMA) isoprenylated plant proteins (HIPPs) only exist in vascular plants. They play important roles in responses to biotic/abiotic stresses, heavy-metal homeostasis, and detoxification. However, research on the distribution, diversification, and function ofHIPPsinTriticeaespecies is limited. In this study, a total of 278HIPPswere identified from a database from fiveTriticeaespecies, and 13 were cloned fromHaynaldia villosa. These genes were classified into five groups by phylogenetic analysis. Most HIPPs had one HMA domain, while 51 from Clade I had two, and allHIPPshad good collinear relationships between species or subgenomes. In silico expression profiling revealed that 44 of the 114 wheatHIPPswere dominantly expressed in roots, 43 were upregulated under biotic stresses, and 29 were upregulated upon drought or heat treatment. Subcellular localization analysis of the clonedHIPPsfromH. villosashowed that they were expressed on the plasma membrane.HIPP1-Vwas upregulated inH. villosaafter Cd treatment, and transgenic wheat plants overexpressingHIPP1-Vshowed enhanced Cd tolerance, as shown by the recovery of seed-germination and root-growth inhibition by supplementary Cd. This research provides a genome-wide overview of theTriticeae HIPPgenes and proved thatHIPP1-Vpositively regulates Cd tolerance in common wheat.