Plant Biotechnology Journal, n/a(n/a). doi:10.1111/pbi.13391

Lichun Huang^#, Qianfeng Li^#, Changquan Zhang^#, Rui Chu, Zhengwen Gu, Hongyan Tan, Dongsheng Zhao, Xiaolei Fan and Qiaoquan Liu*

Abstract

In rice, the Waxy (Wx) gene encoding GBSSI (granule-bound starch synthase I) controls amylose synthesis in the endosperm and is the primary factor influencing grain eating and cooking quality (ECQ). The natural allelic variations within the Wx locus cause the broad diversity of amylose content (AC) and ECQ in modern rice. In this study, we report to create novel Wx alleles with the aim to fine-turn its expression and grain AC, thus catering for the unique preferences of populations from different cultures. Here, the core region of Wx promoter was selected for genome editing and six novel transgene-free Wx alleles were generated. The Wx expression was down-regulated and AC was fine-tuned in the rice. Among the novel Wx alleles, Wx^b-d8, with a moderate and stable decrease in rice AC under various temperature conditions, has a potential application in rice breeding. While other alleles, whose performances depended on temperature conditions, could also be applied in the improvement of rice quality based on local temperatures and consumer preferences. Therefore, this study provides new germplasm resources for rice breeding and efficient method for creating more novel Wx alleles with a wider range of Wx expression and grain AC. Moreover, it also demonstrated that targeted modification of gene core promoter is a universal and reliable approach for the fine-tuning of the expression of target genes.

全文链接：

https://onlinelibrary.wiley.com/doi/abs/10.1111/pbi.13391