J Integr Plant Biol. ›› 2021, Vol. 63 ›› Issue (5): 889-901.DOI: 10.1111/jipb.13010

Special Issue: Crop yield Seed development Grain quality

• Molecular Physiology • Previous Articles     Next Articles

A rare Waxy allele coordinately improves rice eating and cooking quality and grain transparency

Changquan Zhang1,2, Yong Yang1, Shengjie Chen2†, Xueju Liu2, Jihui Zhu1,2, Lihui Zhou2, Yan Lu2, Qianfeng Li1,2, Xiaolei Fan1,2, Shuzhu Tang1,2, Minghong Gu1,2 and Qiaoquan Liu1,2*   

  1. 1Key Laboratory of Crop Genomics and Molecular Breeding of Jiangsu Province, State Key Laboratory of Hybrid Rice, Yangzhou University, Yangzhou 225009, China
    2Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu Key Laboratory of Crop Genetics and Physiology/Co‐ Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province, Yangzhou University, Yangzhou 225009, China
    Present address: State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China

    *Correspondence: Qiaoquan Liu (qqliu@yzu.edu.cn)
  • Received:2020-07-28 Accepted:2020-09-02 Online:2020-09-04 Published:2021-05-01

Abstract: In rice (Oryza sativa), amylose content (AC) is the major factor that determines eating and cooking quality (ECQ). The diversity in AC is largely attributed to natural allelic variation at the Waxy (Wx) locus. Here we identified a rare Wx allele, Wxmw, which combines a favorable AC, improved ECQ and grain transparency. Based on a phylogenetic analysis of Wx genomic sequences from 370 rice accessions, we speculated that Wxmw may have derived from recombination between two important natural Wx alleles, Wxin and Wxb. We validated the effects of Wxmw on rice grain quality using both transgenic lines and near‐isogenic lines (NILs). When introgressed into the japonica Nipponbare (NIP) background, Wxmw resulted in a moderate AC that was intermediate between that of NILs carrying the Wxb allele and NILs with the Wxmp allele. Notably, mature grains of NILs fixed for Wxmw had an improved transparent endosperm relative to soft rice. Further, we introduced Wxmw into a high‐yielding japonica cultivar via molecular marker‐assisted selection: the introgressed lines exhibited clear improvements in ECQ and endosperm transparency. Our results suggest that Wxmw is a promising allele to improve grain quality, especially ECQ and grain transparency of high‐yielding japonica cultivars, in rice breeding programs.

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