Genetic analysis and molecular mapping of maize (Zea mays L.) stalk rot resistant gene Rfg1

Abstract

One single pathogen Fusarium graminearum Schw. was inoculated to maize inbred lines 1,145 (Resistant) and Y331 (Susceptive), and their progenies of F(1), F(2) and BC(1)F(1) populations. Field statistical data revealed that all of the F(1) individuals were resistant to the disease and that the ratio of resistant plants to susceptive plants was 3:1 in the F(2) population, and 1:1 in the BC(1)F(1 )population. The results revealed that a single dominant gene controls the resistance to F. graminearum Schw. The resistant gene to F. graminearum Schw. was denominated as Rfg1 according to the standard principle of the nomenclature of the plant disease resistant genes. RAPD (randomly amplified polymorphic DNA) combined with BSA (bulked segregant analysis) analysis was carried out in the developed F(2) and BC(1)F(1 )populations, respectively. Three RAPD products screened from the RAPD analysis with 820 Operon 10-mer primers showed the linkage relation with the resistant gene Rfg1. The three RAPD amplification products (OPD-20(1000), OPA-04(1100) and OPY-04(900)) were cloned and their copy numbers were determined. The results indicated that only OPY-04(900) was a single-copy sequence. Then, OPY-04(900) was used as a probe to map the Rfg1 gene with a RIL F(7) mapping population provided by Henry Nguyen, which was developed from the cross "S3xMo17". Rfg1 was primarily mapped on chromosome 6 between the two linked markers OPY-04(900) and umc21 (Bin 6.04-6.05). In order to confirm the primary mapping result, 25 SSR (simple sequence repeat) markers and six RFLP (restriction fragment length polymorphism) markers in the Rfg1 gene-encompassing region were selected, and their linkage relation with Rfg1 was analyzed in our F(2) population. Results indicated that SSR marker mmc0241 and RFLP marker bnl3.03 are flanking the Rfg1 gene with a genetic distance of 3.0 cM and 2.0 cM, respectively. This is the first time to name and to map a single resistant gene of maize stalk rot through a single pathogen inoculation and molecular marker analysis.

Characterization and mapping of Rpi1, a gene that confers dominant resistance to stalk rot in maize

“…Relationship between QTLs and dominant resistance to maize stalk rot It is interesting that the dominant genes for resistance to maize stalk rot cauded by P. inflatum (Rpi1) and C. graminearum (Rfg1) reported by us (Yang et al 2004, and this paper) are located on chromosomes 6 and 4, respectively. Their map positions overlap with QTLs reported by Pe et al (1993).…”

“…Meanwhile, we have analyzed resistance in a segregating population developed following singlepathogen inoculation with Fusarium graminearum Schw., and found that the resistance to this pathogen was controlled by a single dominant gene (Yang et al 2002b). Later, the resistance gene Rfg1 (resistance to F. graminearum Schw) was tagged and mapped to chromosome 6 (Yang et al 2004).…”

Qualitative and Quantitative Trait Polymorphisms in Maize

“…QTLs conferring resistance to F. graminearum have been mapped on chromosomes 1, 3, 4, 5, 6, and 10 (Pe et al 1993;Yang et al 2004Yang et al , 2010a. A major QTL qRfg1, located in bin 10.04, was delimited into an interval of 500 kb ); while, a minor QTL, qRfg2, has been fine-mapped into a 300 kb interval with a putative candidate gene coding for an auxin-regulated protein (Zhang et al 2012).…”

Identificação de marcador RAPD e SCAR relacionados ao caractere florescimento precoce em <i>Eucalyptus grandis</i>.

“…Yang et al (2004) utilizaram 820 marcadores e progênies F1 e F2 para o mapeamento de um gene de resistência em milho; em cevada, foram necessários 186 "primers" e a análise de 140 linhagens para a identificação de genes de resistência por BSA (Kutcher et al, 1996). No entanto, o presente trabalho demonstra que a BSA tem grande utilidade em programas de melhoramento genético de espécies florestais, e em especial do eucalipto, pois, com um grupo inicial de 20 indivíduos (os "bulks") e algumas dezenas de "primers" RAPD, já puderam ser localizados marcadores relacionados ao florescimento precoce.…”