Pingli Chen, Guanjun Gao, Guangming Lou, Jie Hu, Yufu Wang, Rongjia Liu, Da Zhao, Qing Liu, Bingrui Sun, Xingxue Mao, Liqun Jiang, Jing Zhang, Shuwei Lv, Hang Yu, Wenfeng Chen, Zhilan Fan, Chen Li, Yuqing He

Int J Mol Sci.; 2023 Sep 22; 24(19):14446. doi: 10.3390/ijms241914446.

Abstract

Rice blast caused by Magnaporthe oryzae is one of the most serious rice diseases worldwide. The early indica rice thermosensitive genic male sterile (TGMS) line HD9802S has the characteristics of stable fertility, reproducibility, a high outcrossing rate, excellent rice quality, and strong combining ability. However, this line exhibits poor blast resistance and is highly susceptible to leaf and neck blasts. In this study, backcross introduction, molecular marker-assisted selection, gene chipping, anther culture, and resistance identification in the field were used to introduce the broad-spectrum blast-resistance gene R6 into HD9802S to improve its rice blast resistance. Six induction media were prepared by varying the content of each component in the culture medium. Murashige and Skoog's medium with 3 mg/L 2,4-dichlorophenoxyacetic acid, 2 mg/L 1-naphthaleneacetic acid, and 1 mg/L kinetin and N6 medium with 800 mg/L casein hydrolysate, 600 mg/L proline, and 500 mg/L glutamine could improve the callus induction rate and have a higher green seedling rate and a lower white seedling rate. Compared to HD9802S, two doubled haploid lines containing R6 with stable fertility showed significantly enhanced resistance to rice blast and no significant difference in spikelet number per panicle, 1000-grain weight, or grain shape. Our findings highlight a rapid and effective method for improving rice blast resistance in TGMS lines.

See https://pubmed.ncbi.nlm.nih.gov/37833893/

Figure 1. Strategy to develop improved populations and resistance identification. (A) Scheme of marker-assisted backcross breeding for improved TGMS line stacking R6 coupled with anther culture used in the current study MAS: marker assistance selection. (B) Haplotype map of genetic background profiling using the RICE6K array The arrow indicates the position of R6 on chromosome 6. The blue lines indicate the SNP loci with heterozygote genotypes where genomic fragments of the donor parent 194-3 were introgressed.