title: Two key genomic regions harbour QTLs for salinity tolerance in ICCV 2 × JG 11 derived chickpea (Cicer arietinum L.) recombinant inbred lines.
abstract: BACKGROUND
  Although chickpea (Cicer arietinum L.), an important food legume crop, is sensitive to salinity, considerable variation for salinity tolerance exists in the germplasm. To improve any existing cultivar, it is important to understand the genetic and physiological mechanisms underlying this tolerance.
  
  
  RESULTS
  In the present study, 188 recombinant inbred lines (RILs) derived from the cross ICCV 2 × JG 11 were used to assess yield and related traits in a soil with 0 mM NaCl (control) and 80 mM NaCl (salinity) over two consecutive years. Salinity significantly (P < 0.05) affected almost all traits across years and yield reduction was in large part related to a reduction in seed number but also a reduction in above ground biomass. A genetic map was constructed using 56 polymorphic markers (28 simple sequence repeats; SSRs and 28 single nucleotide polymorphisms; SNPs). The QTL analysis revealed two key genomic regions on CaLG05 (28.6 cM) and on CaLG07 (19.4 cM), that harboured QTLs for six and five different salinity tolerance associated traits, respectively, and imparting either higher plant vigour (on CaLG05) or higher reproductive success (on CaLG07). Two major QTLs for yield in the salinity treatment (explaining 12 and 17% of the phenotypic variation) were identified within the two key genomic regions. Comparison with already published chickpea genetic maps showed that these regions conferred salinity tolerance across two other populations and the markers can be deployed for enhancing salinity tolerance in chickpea. Based on the gene ontology annotation, forty eight putative candidate genes responsive to salinity stress were found on CaLG05 (31 genes) and CaLG07 (17 genes) in a distance of 11.1 Mb and 8.2 Mb on chickpea reference genome. Most of the genes were known to be involved in achieving osmoregulation under stress conditions.
  
  
  CONCLUSIONS
  Identification of putative candidate genes further strengthens the idea of using CaLG05 and CaLG07 genomic regions for marker assisted breeding (MAB). Further fine mapping of these key genomic regions may lead to novel gene identification for salinity stress tolerance in chickpea.
authors.affiliation: International Crops Research Institute for the Semi-Arid Tropics, Patancheru 502 234, Telangana State, India. pushpavalli11@gmail.com.|Department of Plant Science, Bharathidasan University, 620024, Tiruchirappalli, Tamil Nadu, India. pushpavalli11@gmail.com.
authors.forename: Raju
authors.initials: R
authors.lastname: Pushpavalli
authors.affiliation: International Crops Research Institute for the Semi-Arid Tropics, Patancheru 502 234, Telangana State, India. l.krishnamurthy@cgiar.org.
authors.forename: Laxmanan
authors.initials: L
authors.lastname: Krishnamurthy
authors.affiliation: International Crops Research Institute for the Semi-Arid Tropics, Patancheru 502 234, Telangana State, India. t.mahendar@cgiar.org.
authors.forename: Mahendar
authors.initials: M
authors.lastname: Thudi
authors.affiliation: International Crops Research Institute for the Semi-Arid Tropics, Patancheru 502 234, Telangana State, India. r.k.varshney@cgiar.org.
authors.forename: Pooran M
authors.initials: PM
authors.lastname: Gaur
authors.affiliation: Department of Plant Science, Bharathidasan University, 620024, Tiruchirappalli, Tamil Nadu, India. p.gaur@cgiar.org.
authors.forename: Mandali V
authors.initials: MV
authors.lastname: Rao
authors.affiliation: The UWA Institute of Agriculture, The University of Western Australia, 35 Stirling Highway, 6009, Crawley, WA, Australia. neil.turner@uwa.edu.au.
authors.forename: Kadambot H M
authors.initials: KH
authors.lastname: Siddique
authors.affiliation: School of Plant Biology, The University of Western Australia, 35 Stirling Highway, 6009, , Crawley, WA, Australia. mvrao_456@yahoo.co.in.
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Colmer
authors.affiliation: The UWA Institute of Agriculture, The University of Western Australia, 35 Stirling Highway, 6009, Crawley, WA, Australia. timothy.colmer@uwa.edu.au.|Centre for Plant Genetics and Breeding, M080, The University of Western Australia, 35 Stirling Highway, 6009, Crawley, WA, Australia. timothy.colmer@uwa.edu.au.
authors.forename: Neil C
authors.initials: NC
authors.lastname: Turner
authors.affiliation: International Crops Research Institute for the Semi-Arid Tropics, Patancheru 502 234, Telangana State, India. kadambot.siddique@uwa.edu.au.|School of Plant Biology, The University of Western Australia, 35 Stirling Highway, 6009, , Crawley, WA, Australia. kadambot.siddique@uwa.edu.au.
authors.forename: Rajeev K
authors.initials: RK
authors.lastname: Varshney
authors.affiliation: International Crops Research Institute for the Semi-Arid Tropics, Patancheru 502 234, Telangana State, India. v.vadez@cgiar.org.
authors.forename: Vincent
authors.initials: V
authors.lastname: Vadez
mesh_terms: D000704:Analysis of Variance; D018533:Biomass; D002874:Chromosome Mapping; D029863:Cicer / Q000235:genetics*; D003433:Crosses, Genetic; D057225:Data Mining; D056726:Genetic Association Studies; D008040:Genetic Linkage; D005819:Genetic Markers; D018745:Genome, Plant; D007178:Inbreeding; D040582:Inheritance Patterns / Q000235:genetics; D040641:Quantitative Trait Loci / Q000235:genetics*; D019655:Quantitative Trait, Heritable; D011995:Recombination, Genetic / Q000235:genetics*; D054712:Salinity; D055049:Salt Tolerance / Q000235:genetics*; D012639:Seeds / Q000235:genetics / Q000254:growth & development; D013312:Stress, Physiological / Q000235:genetics
chemical_list: D005819:Genetic Markers