Mining of loss-of-function alleles on starch synthesis gene TaSSIVb-D by TILLING and characterization of their effects in wheat

15^th Asia-Pacific Biotechnology Congress

July 20-22, 2017 Melbourne, Australia

Huijun Guo, Yongdun Xie, Hongchun Xiong, Linshu Zhao, Jiayu Gu, Shirong Zhao and Luxiang Liu

Chinese Academy of Agricultural Sciences, China

Posters & Accepted Abstracts: J Bioprocess Biotech

Abstract :

TILLING (Targeting-Induced Local Lesions in Genomes) is a powerful approach for novel allele identification and has been used to screen mutagenized plant populations for novel alleles of target genes. Starch synthesis IV (SSIV) is one of the important starch synthase isoforms for transient starch synthesis but its impact on wheat starch synthesis has not yet been reported due to the lack of mutant lines. Using the TILLING approach and an EMS mutagenized population containing 3058 M2 individuals, we identified 54 mutations in the wheat gene TaSSIVb-D, with a mutation density of 1/165 Kb. Among these mutations, 26 are in the coding region, including 1 nonsense mutation (E054-13), 15 missense mutations and 10 silent mutations. Using SIFT program, 3 missense mutations and 1 nonsense mutation were predicted to have severe impacts on protein function. Results of RT-qPCR, transmission electron microscope and chlorophyll fluorescence analysis showed that, TaSSIVb-D was significantly down-regulated without compensatory increases in the homologous genes TaSSIVb-A and TaSSIVb-B. Altered expression of TaSSIVb-D reduced granule number per chloroplast compared with wild type; photosynthesis was affected accordingly. These results indicate that TILLING approach and our mutagenized population allows efficient identification of novel loss-of-functional alleles of target genes.

Biography :

Huijun Guo has her expertise in wheat mutation breeding for new germplasm and novel alleles’ development. She has mined a series of novel alleles on starch synthesis key genes, built a high-capacity mutant library with gradient phenotypic variation that contains over 4,000 lines and mutant phenotypes include plant height, tillering capacity, panicle length, 1000-grain weight and many other important agronomic traits and cooperated with other breeders to breed four new varieties. She was awarded three national invention patents, one new plant variety right and has applied for one patent and five variety rights. She has published more than 40 research papers and was awarded one outstanding contribution award for wheat mutation breeding by FAO/IAEA.

Email: guohuijun@caas.cn