Journal Article

Novel mutant alleles of the starch synthesis gene TaSSIVb-D result in the reduction of starch granule number per chloroplast in wheat

Zhao, Shirong, Liu, Luxiang, Xie, Yongdun, Liu, Yunchuan, Guo, Huijun, Xiong, Hongchun, Li, Xiao, Gu, Jiayu, Yan, Zhihui, Zhao, Linshu

2017

Overview

Background Transient starch provides carbon and energy for plant growth, and its synthesis is regulated by the joint action of a series of enzymes. Starch synthesis IV (SSIV) is one of the important starch synthase isoforms, but its impact on wheat starch synthesis has not yet been reported due to the lack of mutant lines. Results Using the TILLING approach, we identified 54 mutations in the wheat gene TaSSIVb - D , with a mutation density of 1/165 Kb. Among these, three missense mutations and one nonsense mutation were predicted to have severe impacts on protein function. In the mutants, TaSSIVb - D was significantly down-regulated without compensatory increases in the homoeologous genes TaSSIVb - A and TaSSIVb - B . Altered expression of TaSSIVb - D affected granule number per chloroplast; compared with wild type, the number of chloroplasts containing 0–2 granules was significantly increased, while the number containing 3–4 granules was decreased. Photosynthesis was affected accordingly; the maximum quantum yield and yield of PSII were significantly reduced in the nonsense mutant at the heading stage. Conclusions These results indicate that TaSSIVb - D plays an important role in the formation of transient starch granules in wheat, which in turn impact the efficiency of photosynthesis. The mutagenized population created in this study allows the efficient identification of novel alleles of target genes and could be used as a resource for wheat functional genomics.

• Publisher: BioMed Central,Springer Nature B.V,BMC
• Subject: Alleles / Animal Genetics and Genomics / Biomedical and Life Sciences / Biosynthesis / Chloroplasts / Chloroplasts - metabolism / Enzymes / Gene expression / Gene Expression Regulation, Plant - genetics / Genes / Genomes / Genomics / Glucose / Granular materials / Impact prediction / Isoforms / Life Sciences / Microarrays / Microbial Genetics and Genomics / Missense mutation / Mutant / Mutation / Nonsense mutant / Nonsense mutation / Photosynthesis / Photosynthesis - genetics / Photosystem II / Photosystem II Protein Complex - metabolism / Plant Genetics and Genomics / Plant genomics / Plant growth / Plant Proteins - genetics / Plant Proteins - metabolism / Population genetics / Population studies / Proteomics / Research Article / Seeds / Starch / Starch - biosynthesis / Starch granule / Starch synthase / TaSSIVb-D / TILLING / Triticum - cytology / Triticum - genetics / Triticum - growth & development / Triticum - metabolism / Wheat