Mengjing Sun, Qiaoling Luo, Qi Zheng, Jingyang Tong, Yue Wang, Jie Song, Yelun Zhang, Zongjun Pu, Jianmin Zheng, Lianzheng Liu, Anding Zhou, Awais Rasheed, Ming Li, Shuanghe Cao, Xianchun Xia, Zhonghu He & Yuanfeng Hao

Theoretical and Applied Genetics October 2023; vol. 136, Article number: 217

Key message

Major QTL for grain zinc and iron concentrations were identified on the long arm of chromosomes 2D and 6D. Gene-based KASP markers were developed for putative candidate genes TaIPK1-2D and TaNAS10-6D.

Abstract

Micronutrient malnutrition is one of the most common public health problems in the world. Biofortification, the most attractive and sustainable solution to surmount malnutrition requires the development of micronutrient enriched new crop cultivars. In this study, two recombinant inbred line (RIL) populations, ZM175/XY60 and ZM175/LX987, were used to identify QTL for grain zinc concentration (GZnC), grain iron concentration (GFeC) and thousand grain weight (TGW). Eight QTL for GZnC, six QTL for GFeC and five QTL for TGW were detected. Three QTL on chromosomes 2DL and 4BS and chromosome 6A showed pleiotropic effects on all three traits. The 4BS and 6A QTL also increased plant height and might be Rht-B1a and Rht25a, respectively. The 2DL locus within a suppressed recombination region was identified in both RIL populations and the favorable allele simultaneously increasing GZnC, GFeC and TGW was contributed by XY60 and LX987. A QTL on chromosome 6DL associated only with GZnC was detected in ZM175/XY60 and was validated in JD8/AK58 RILs using kompetitive allele-specific PCR (KASP) marker K_AX-110119937. Both the 2DL and 6DL QTL were new loci for GZnC. Based on gene annotations, sequence variations and expression profiles, the phytic acid biosynthesis gene TaIPK1-2D and nicotianamine synthase gene TaNAS10-6D were predicted as candidate genes. Their gene-based KASP markers were developed and validated in a cultivar panel of 343 wheat accessions. This study investigated the genetic basis of GZnC and GFeC and provided valuable candidate genes and markers for breeding Zn- and Fe-enriched wheat.

See: https://link.springer.com/article/10.1007/s00122-023-04467-y

Figure: The locations of iron and zinc in wheat grain. (a) Transverse sections through wheat grains, showing the position of the embryo (Em), starchy endosperm (ES), aleurone (Al), groove (gr) and bran and the locations of iron (light blue from staining with Prussian blue in upper image) and zinc (red from staining with dithizone in lower image). (b) Heat map representation of the distribution of iron (Fe) and zinc (Zn) in longitudinal and transverse sections of wheat grain, revealed by X-ray fluorescence. Taken from Neal et al. (2013) with permission. Labelling as in Panel (a). (c) NanoSIMS images of an aleurone cell of an immature wheat grain showing localisation of 56 Fe 16 O À to the phytin globoids (as indicated by the 31 P 16 O À image). White indicates high signal intensity. Taken from Moore et al. (2012) with permission.

(https://www.researchgate.net/figure/The-locations-of-iron-and-zinc-in-wheat-grain-a-Transverse-sections-through-wheat_fig1_330668146)