title: Salt-stress induced changes in the leaf proteome of diploid and tetraploid mandarins with contrasting Na+ and Cl- accumulation behaviour.
abstract: To understand the genotypic variation of citrus to mild salt stress, a proteomic approach has been carried out in parallel on two citrus genotypes ('Cleopatra' and 'Willow leaf' mandarins), which differ for Na(+) and Cl(-) accumulation, and their cognate autotetraploids (4×). Using two-dimensional electrophoresis approximately 910 protein spots were reproducibly detected in control and salt-stressed leaves of all genotypes. Among them, 44 protein spots showing significant variations at least in one genotype were subjected to mass spectrometry analysis for identification. Salt-responsive proteins were involved in several functions, including photosynthetic processes, ROS scavenging, stress defence, and signalling. Genotype factors affect the salt-responsive pattern, especially that of carbon metabolism. The no ion accumulator 'Cleopatra' mandarin genotype showed the highest number of salt-responsive proteins, and up-regulation of Calvin cycle-related proteins. Conversely the ion accumulator 'Willow leaf' mandarin showed high levels of several photorespiration-related enzymes. A common set of proteins (twelve spots) displayed higher levels in salt-stressed leaves of 2× and 4× 'Cleopatra' and 4× 'Willow leaf' mandarin. Interestingly, antioxidant enzymes and heat shock proteins showed higher constitutive levels in 4× 'Cleopatra' mandarin and 4× 'Willow leaf' mandarin compared with the cognate 2× genotype. This work provides for the first time information on the effect of 8 weeks of salt stress on citrus genotypes contrasting for ion accumulation and their cognate autotetraploids. Results underline that genetic factors have a predominant effect on the salt response, although a common stress response independent from genotype was also found.
authors.affiliation: CNR-IBF, Istituto di BioFisica, Area della Ricerca, Via Moruzzi 1, I-56124 Pisa, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Podda
authors.forename: Giovanni
authors.initials: G
authors.lastname: Checcucci
authors.forename: Wafa
authors.initials: W
authors.lastname: Mouhaya
authors.forename: Delphine
authors.initials: D
authors.lastname: Centeno
authors.forename: Valerie
authors.initials: V
authors.lastname: Rofidal
authors.forename: Renata
authors.initials: R
authors.lastname: Del Carratore
authors.forename: François
authors.initials: F
authors.lastname: Luro
authors.forename: Raphael
authors.initials: R
authors.lastname: Morillon
authors.forename: Patrick
authors.initials: P
authors.lastname: Ollitrault
authors.forename: Bianca Elena
authors.initials: BE
authors.lastname: Maserti
mesh_terms: D002712:Chlorides / Q000378:metabolism; D002957:Citrus / Q000187:drug effects / Q000378:metabolism*; D004171:Diploidy; D018515:Plant Leaves / Q000187:drug effects* / Q000378:metabolism*; D020543:Proteome / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology*; D057891:Tetraploidy
chemical_list: D002712:Chlorides; D020543:Proteome; D012965:Sodium Chloride; D012964:Sodium