title: Genome-wide expression profiling of aquaporin genes confer responses to abiotic and biotic stresses in Brassica rapa.
abstract: Plants contain a range of aquaporin (AQP) proteins, which act as transporter of water and nutrient molecules through living membranes. AQPs also participate in water uptake through the roots and contribute to water homeostasis in leaves.
  
  
  
  In this study, we identified 59 AQP genes in the B. rapa database and Br135K microarray dataset. Phylogenetic analysis revealed four distinct subfamilies of AQP genes: plasma membrane intrinsic proteins (PIPs), tonoplast intrinsic proteins (TIPs), NOD26-like intrinsic proteins (NIPs) and small basic intrinsic proteins (SIPs). Microarray analysis showed that the majority of PIP subfamily genes had differential transcript abundance between two B. rapa inbred lines Chiifu and Kenshin that differ in their susceptibility to cold. In addition, all BrPIP genes showed organ-specific expression. Out of 22 genes, 12, 7 and 17 were up-regulated in response to cold, drought and salt stresses, respectively. In addition, 18 BrPIP genes were up-regulated under ABA treatment and 4 BrPIP genes were up-regulated upon F. oxysporum f. sp. conglutinans infection. Moreover, all BrPIP genes showed down-regulation under waterlogging stress, reflecting likely the inactivation of AQPs controlling symplastic water movement.
  
  
  
  This study provides a comprehensive analysis of AQPs in B. rapa and details the expression of 22 members of the BrPIP subfamily. These results provide insight into stress-related biological functions of each PIP gene of the AQP family, which will promote B. rapa breeding programs.
authors.affiliation: Department of Horticulture, Sunchon National University, 255 Jungang-ro, Suncheon, Jeonnam, 57922, South Korea.
authors.forename: Md Abdul
authors.initials: MA
authors.lastname: Kayum
authors.affiliation: Department of Horticulture, Sunchon National University, 255 Jungang-ro, Suncheon, Jeonnam, 57922, South Korea.
authors.forename: Jong-In
authors.initials: JI
authors.lastname: Park
authors.affiliation: Department of Horticulture, Sunchon National University, 255 Jungang-ro, Suncheon, Jeonnam, 57922, South Korea.
authors.forename: Ujjal Kumar
authors.initials: UK
authors.lastname: Nath
authors.affiliation: Department of Horticulture, Sunchon National University, 255 Jungang-ro, Suncheon, Jeonnam, 57922, South Korea.
authors.forename: Manosh Kumar
authors.initials: MK
authors.lastname: Biswas
authors.affiliation: University-Industry Cooperation Foundation, Sunchon National University, 255 Jungang-ro, Suncheon, Jeonnam, 57922, South Korea.
authors.forename: Hoy-Taek
authors.initials: HT
authors.lastname: Kim
authors.affiliation: Department of Horticulture, Sunchon National University, 255 Jungang-ro, Suncheon, Jeonnam, 57922, South Korea. nis@sunchon.ac.kr.
authors.forename: Ill-Sup
authors.initials: IS
authors.lastname: Nou
mesh_terms: D020346:Aquaporins / Q000235:genetics*; D029741:Brassica rapa / Q000235:genetics*; D002874:Chromosome Mapping; D032461:Chromosomes, Plant; D018744:DNA, Plant; D005091:Exons; D020869:Gene Expression Profiling; D017343:Genes, Plant; D007438:Introns; D010100:Oxygen / Q000378:metabolism; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics*; D040081:Protein Array Analysis; D017422:Sequence Analysis, DNA; D013312:Stress, Physiological
chemical_list: D020346:Aquaporins; D018744:DNA, Plant; D010940:Plant Proteins; D010100:Oxygen
keywords: Abiotic stress; Aquaporin; Biotic stress; Brassica rapa; Gene expression