The down-regulation of the genes encoding Isoamylase 1 alters the starch composition of the durum wheat grain. (November 2016)

• Record Type: Journal Article
• Authors: Sestili, Francesco; Sparla, Francesca; Botticella, Ermelinda; Janni, Michela; D'Ovidio, Renato; Falini, Giuseppe; Marri, Lucia; Cuesta-Seijo, Jose A.; Moscatello, Stefano; Battistelli, Alberto; Trost, Paolo; Lafiandra, Domenico
• Is Part Of: Plant science. Volume 252(2016:Nov.)
• Page Start: 230
• Page End: 238
• Publication Date: 2016-11
• Subjects: CSLF6 cellulose synthase like F6 -- DP degree polymerization -- HPAEC-PAD High-Performance Anion-Exchange Chromatography Coupled with Pulsed Electrochemical Detection -- ISA1 Isoamylase 1 -- ISA2 Isoamylase 2 -- ISA3 Isoamylase 3 -- PUL pullulanase -- qRT-PCR quantitative real time PCR -- RNAi RNA interference -- SEM scanning electron microscopy -- SUSY sucrose synthase; Starch -- Isoamylases -- RNAi -- Durum wheat; Botany -- Periodicals; Botanique -- Périodiques; 580
• DOI: 10.1016/j.plantsci.2016.08.001
• Languages: English
• ISSNs: 0168-9452

Abstract

Highlights: The silencing of Isa1 affects the gene expression of the other debranching enzymes. RNAi ISA1 plants show a reduction in the content of starch. RNAi ISA1 plants result in an increase of phytoglycogen and β-glucans. The distribution of amylopectin chain length is altered in RNAi ISA1 plants. Abstract: In rice, maize and barley, the lack of Isoamylase 1 activity materially affects the composition of endosperm starch. Here, the effect of this deficiency in durum wheat has been characterized, using transgenic lines in which Isa1 was knocked down via RNAi. Transcriptional profiling confirmed the partial down-regulation of Isa1 and revealed a pleiotropic effect on the level of transcription of genes encoding other isoamylases, pullulanase and sucrose synthase. The polysaccharide content of the transgenic endosperms was different from that of the wild type in a number of ways, including a reduction in the content of starch and a moderate enhancement of both phytoglycogen and β-glucan. Some alterations were also induced in the distribution of amylopectin chain length and amylopectin fine structure. The amylopectin present in the transgenic endosperms was more readily hydrolyzable after a treatment with hydrochloric acid, which disrupted its semi-crystalline structure. The conclusion was that in durum wheat, Isoamylase 1 is important for both the synthesis of amylopectin and for determining its internal structure.