1Sl(1B) Chromosome substitution in Chinese Spring wheat promotes starch granule development and starch biosynthesis

Abstract

The common wheat variety Chinese Spring (CS) chromosome substitution line CS-1Sl(1B) was used in this study, in which the 1B chromosome in CS (Triticum aestivum L., 2n = 6x = 42, AABBDD) was substituted by the 1Sl from Aegilops longissima (2n = 2x = 14, SlSl). The results showed that the substitution of 1B in CS by 1Sl chromosome could significantly increase amylopectin and total starch contents. The dynamic changes in starch granules during grain development in CS and CS-1Sl(1B) demonstrated that the substitution line possessed higher amount of A-type starch granules and greater diameter of both A- and B-granules. qRT-PCR revealed that some key genes involved in starch biosynthesis, such as starch synthases (SSI, SSII and SSIII), starch branching enzymes (SBE IIa and SBE IIb) and granule-bound starch synthase (GBSS I), displayed higher transcript levels of mRNA expressions during grain development in CS-1Sl(1B). Our results indicate that the substituted 1Sl chromosome carries important genes that influence starch granule development and starch biosynthesis, which may be used as potential gene resources for improvement of wheat starch quality.