Development of 25 near-isogenic lines (NILs) with ten BPH resistance genes in rice (Oryza sativa L.): production, resistance spectrum, and molecular analysis

Abstract

A first set of 25 NILs carrying ten BPH resistance genes and their pyramids was developed in the background of indica variety IR24 for insect resistance breeding in rice. Brown planthopper (Nilaparvata lugens Stal.) is one of the most destructive insect pests in rice. Development of near-isogenic lines (NILs) is an important strategy for genetic analysis of brown planthopper (BPH) resistance (R) genes and their deployment against diverse BPH populations. A set of 25 NILs with 9 single R genes and 16 multiple R gene combinations consisting of 11 two-gene pyramids and 5 three-gene pyramids in the genetic background of the susceptible indica rice cultivar IR24 was developed through marker-assisted selection. The linked DNA markers for each of the R genes were used for foreground selection and confirming the introgressed regions of the BPH R genes. Modified seed box screening and feeding rate of BPH were used to evaluate the spectrum of resistance. BPH reaction of each of the NILs carrying different single genes was variable at the antibiosis level with the four BPH populations of the Philippines. The NILs with two- to three-pyramided genes showed a stronger level of antibiosis (49.3-99.0%) against BPH populations compared with NILs with a single R gene NILs (42.0-83.5%) and IR24 (10.0%). Background genotyping by high-density SNPs markers revealed that most of the chromosome regions of the NILs (BCF) had IR24 genome recovery of 82.0-94.2%. Six major agronomic data of the NILs showed a phenotypically comparable agronomic performance with IR24. These newly developed NILs will be useful as new genetic resources for BPH resistance breeding and are valuable sources of genes in monitoring against the emerging BPH biotypes in different rice-growing countries.

Mapping of a major QTL, qBK1Z, for bakanae disease resistance in rice

“…For example, Yasuda et al (2015) reported rice lines with pairs of blast resistance genes to be only comparable to lines with a single gene which may have a stronger suppressive effect. Similarly, pyramiding of brown planthopper (BPH) resistance genes in a susceptible variety IR24 markedly improved BPH resistance against four BPH populations in the Philippines than the single BPH introgressed lines (Jena et al 2017). In our previous study of bakanae disease resistance (Lee et al 2018) revealed that the gene pyramided lines harboring qBK1 WD + qBK1 had a much higher level of resistance than those possessing either qBK1 WD or qBK1.…”

Comparative transcriptome analysis reveals that tricarboxylic acid cycle-related genes are associated with maize CMS-C fertility restoration

“…In fact, NILs always present extensive residual heterozygosity because of the complexity of genomic composition and recombination [ 32 , 33 ]. Moreover, previous studies in which SNP chips were used have generally reported the presence of SNPs between NILs [ 34 – 36 ]. Compared to SNP chips, next-generation sequencing has a broader and more sensitive detection ability, which might also explain why we detected more SNPs than did previous researchers.…”

Loss of Resistance to <i>Nilaparvata lugens</i> May Be Due to the Low-Level Expression of <i>BPH32 </i>in Rice Panicles at the Heading Stage

“…New rice varieties with BPH resistance have been developed and introduced to farmers [1]. The BPH32 gene is still used in rice breeding programs [20], and the functional DNA markers of this gene have been developed for MAS [21].…”

“…Before and after BPH infestation, the average expression level of BPH32 constantly remained high in the leaf sheath tissue indicating that the gene function may not be induced by the BPH infestation. [21]. The NILs will be useful as new genetic resources for BPH resistance breeding.…”