Improving the blast resistance of the elite rice variety Kongyu-131 by updating the pi21 locus

Abstract

Background As an elite japonica rice variety, Kongyu-131 has been cultivated for over 20 years in the third accumulated temperature zone of Heilongjiang Province, China. However, the cultivated area of Kongyu-131 has decreased each year due to extensive outbreaks of rice blast. To achieve the goals of improving blast resistance and preserving other desirable traits in Kongyu-131, a genome-updating method similar to repairing a bug in a computer program was adopted in this study. A new allele of the broad-spectrum blast resistance gene pi21 in the upland rice variety GKGH was mined by genetic analysis and introgressed into the genome of Kongyu-131 to upgrade its blast resistance. Result QTL analysis was performed with an F 2 population derived from a cross between Kongyu-131 and GKGH, and a blast resistance QTL was detected near the pi21 locus. Parental Pi21 sequence alignment showed that the pi21 of the donor (GKGH) was a new allele. By 5 InDel or SNP markers designed based on the sequence within and around pi21 , the introgressed chromosome segment was shortened to less than 634 kb to minimize linkage drag by screening recombinants in the target region. The RRPG was 99.92%, calculated according to 201 SNP markers evenly distributed on 12 chromosomes. Artificial inoculation at the seedling stage showed that the blast resistance of the new Kongyu-131 was improved significantly. Field experiments also indicated that the improved Kongyu-131 had enhanced field resistance to rice blast and grain-quality traits similar to those of the original Kongyu-131. Conclusions It is feasible to improve resistance to rice blast and preserve other desirable traits by precisely improving the Pi21 locus of Kongyu-131. Linkage drag can be eliminated effectively via recombinant selection on both sides of the target gene.

Association of Clubroot Resistance Locus PbBa8.1 With a Linkage Drag of High Erucic Acid Content in the Seed of the European Turnip

“…In tomato, the linkage breakdown of nematode resistance and undesirable fruit characteristics took 12 years to separate (Acquaah, 2012). However, in rice blast resistance, linkage drag was effectively removed in two cycles of recombinant selection (Feng et al, 2019). Cao et al (2010) reported that backcross breeding and marker-assisted selection are effective tools to break linkage drag between low oil content and erucic acid in canola cultivars.…”

Efficient marker-assisted breeding for clubroot resistance in elite Pol-CMS rapeseed varieties by updating the PbBa8.1 locus

“…Traditional MAS may result in the introduction of undesirable genes, or loss of desirable traits with unclear genetic backgrounds. In addition to foreground selection, background selection is essential as it is more accurate and e cient (Feng et al 2019). Recently, a Bnapus50K array that provides precise genomic information on Chinese local accessions of B. napus was developed (Xiao et al 2021).…”

Recent Progress in Rice Broad-Spectrum Disease Resistance

“…Unlike most blast R genes, Ptr , which is required for broad-spectrum blast resistance mediated by R genes Pita and Pita2 , encodes a four Armadillo (ARM) repeat protein. Furthermore, more alleles or natural variation of broad-spectrum blast resistance R genes have been investigated, including geographically distinct and domain-specific sequence variations of Pib , novel alleles of Pik locus Pi1 , Pike, and Pikg , Pi54 alleles, novel Pi21 haplotypes, and novel alleles of Pi2/9 locus [ 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ]. In addition, four broad-spectrum resistance R genes, Pi-hk1 , Pi57 ( t ), Pi65 ( t ), and Pi69 ( t ), were finely mapped in the past 10 years [ 23 , 24 , 25 , 26 ].…”