title: TILLING mutants of durum wheat result in a high amylose phenotype and provide information on alternative splicing mechanisms.
abstract: The amylose/amylopectin ratio has a major influence over the properties of starch and determines its optimal end use. Here, high amylose durum wheat has been bred by combining knock down alleles at the two homoelogous genes encoding starch branching enzyme IIa (SBEIIa-A and SBEIIa-B). The complete silencing of these genes had a number of pleiotropic effects on starch synthesis: it affected the transcriptional activity of SBEIIb, ISA1 (starch debranching enzyme) and all of the genes encoding starch synthases (SSI, SSIIa, SSIII and GBSSI). The starch produced by grain of the double SBEIIa mutants was high in amylose (up to ∼1.95 fold that of the wild type) and contained up to about eight fold more resistant starch. A single nucleotide polymorphism adjacent to the splice site at the end of exon 10 of the G364E mutant copies of both SBEIIa-A and SBEIIa-B resulted in the loss of a conserved exonic splicing silencer element. Its starch was similar to that of the SBEIIa double mutant. G364E SBEIIa pre-mRNA was incorrectly processed, resulting in the formation of alternative, but non-functional splicing products.
authors.affiliation: Department of Agriculture, Forestry, Nature & Energy, University of Tuscia, Via S Camillo de Lellis SNC, 01100 Viterbo, Italy. Electronic address: francescosestili@unitus.it.
authors.forename: Francesco
authors.initials: F
authors.lastname: Sestili
authors.affiliation: Department of Agriculture, Forestry, Nature & Energy, University of Tuscia, Via S Camillo de Lellis SNC, 01100 Viterbo, Italy. Electronic address: samuela.p85@gmail.com.
authors.forename: Samuela
authors.initials: S
authors.lastname: Palombieri
authors.affiliation: Department of Agriculture, Forestry, Nature & Energy, University of Tuscia, Via S Camillo de Lellis SNC, 01100 Viterbo, Italy. Electronic address: e.botticella@unitus.it.
authors.forename: Ermelinda
authors.initials: E
authors.lastname: Botticella
authors.affiliation: Società Produttori Sementi Spa, Via Macero 1, 40050 Argelato, Bologna, Italy. Electronic address: p.mantovani@prosementi.com.
authors.forename: Paola
authors.initials: P
authors.lastname: Mantovani
authors.affiliation: Società Produttori Sementi Spa, Via Macero 1, 40050 Argelato, Bologna, Italy; Department of Agricultural Science (DipSA), University of Bologna, Viale Fanin 44, 40127 Bologna, Italy. Electronic address: riccardo.bovina@studio.unibo.it.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Bovina
authors.affiliation: Department of Agriculture, Forestry, Nature & Energy, University of Tuscia, Via S Camillo de Lellis SNC, 01100 Viterbo, Italy. Electronic address: lafiandr@unitus.it.
authors.forename: Domenico
authors.initials: D
authors.lastname: Lafiandra
mesh_terms: D015061:1,4-alpha-Glucan Branching Enzyme / Q000235:genetics* / Q000378:metabolism; D017398:Alternative Splicing; D000688:Amylose / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D020868:Gene Silencing; D020125:Mutation, Missense; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014908:Triticum / Q000235:genetics* / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D012333:RNA, Messenger; D000688:Amylose; D015061:1,4-alpha-Glucan Branching Enzyme
keywords: Alternative splicing; Durum wheat; High amylose; Resistant starch; TILLING; mRNA processing