Identification of novel genes for improvement of downy mildew resistance in <i>Zea mays</i>

Abstract. Ashan MD, Miftahudin, Reflinur, Pabendon MB, Santoso SB, Salim A. 2020. QTL Mapping linked to downy mildew resistance genes in maize (Zea mays). Biodiversitas 21: 3735-3743. Downy Mildew (DM) caused by Peronosclerospora spp. is one of the most destructive diseases and problems in yield losses of maize production worldwide. Identification of molecular marker-linked to the DM resistance genes is considered as an important step in the improvement of the DM resistance nature in maize breeding program. The objective of the study was to identify molecular markers linked to the DM resistance genes in maize. A total of 198 F3 maize lines generated from a cross between R10-4430 and Kandora was used in microsatellite genetic map construction and the corresponding F3: 4 families were used in phenotypic evaluation to identify quantitative trait loci (QTLs) responsible for DM resistance-related trait. The entire genetic linkage map constructed with 28 SSR markers resulted in 460.3 cM with an average distance between markers of 26.85 cM. Seven main-effect QTLs controlling the DM resistance genes were identified in the entire genome map of F3 population with the phenotypic variation explained (PVE) values ranged from 43.35 to 53.71%. Among detected QTLs, three QTLs, qDM-Pp1a, qDM-Pp1b1, and qDM-Pp1b2 were detected on chromosome 1, one QTL, qDM-Pp5 was on chromosome 5, two QTLs, qDM-Pp6b1 and qDM-Pp6b2 were on chromosome 6 and one QTL, qDM-Pp10 was on chromosome 10. The effect of detected QTLs responsible for DM resistance trait ranged from 43.35 to 53.71% and those will be potential to be further used as molecular aided selection in maize breeding for DM resistance.

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Downy mildew resistance in maize (Zea mays L.) across Peronosclerospora species in lowland tropical Asia

Crop Protection ◽

10.1016/j.cropro.2012.08.007 ◽

2013 ◽

Vol 43 ◽

pp. 183-191 ◽

Cited By ~ 5

Author(s):

Zerka Rashid ◽

P.H. Zaidi ◽

M.T. Vinayan ◽

S.S. Sharma ◽

T.A. Srirama Setty

Keyword(s):

Zea Mays ◽

Downy Mildew ◽

Zea Mays L ◽

Downy Mildew Resistance ◽

Mildew Resistance ◽

Tropical Asia

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SCREENING TECHNIQUES FOR DOWNY MILDEW RESISTANCE IN GHERKIN CUCUMBERS

International Journal of Geomate ◽

10.21660/2017.40.2603 ◽

2017 ◽

Vol 13 (40) ◽

Author(s):

Piyavadee Charoenwattana

Keyword(s):

Downy Mildew ◽

Downy Mildew Resistance ◽

Mildew Resistance ◽

Screening Techniques

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High resolution mapping and candidate gene identification of downy mildew race 16 resistance in spinach

BMC Genomics ◽

10.1186/s12864-021-07788-8 ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Gehendra Bhattarai ◽

Wei Yang ◽

Ainong Shi ◽

Chunda Feng ◽

Braham Dhillon ◽

...

Keyword(s):

Candidate Genes ◽

Downy Mildew ◽

Association Analysis ◽

Spinacia Oleracea ◽

Genotyping By Sequencing ◽

Significant Snps ◽

Snp Markers ◽

Resistance Locus ◽

Downy Mildew Resistance ◽

Mildew Resistance

Abstract Background Downy mildew, the most devastating disease of spinach (Spinacia oleracea L.), is caused by the oomycete Peronospora effusa [=P. farinosa f. sp. spinaciae]. The P. effusa shows race specificities to the resistant host and comprises 19 reported races and many novel isolates. Sixteen new P. effusa races were identified during the past three decades, and the new pathogen races are continually overcoming the genetic resistances used in commercial cultivars. A spinach breeding population derived from the cross between cultivars Whale and Lazio was inoculated with P. effusa race 16 in an environment-controlled facility; disease response was recorded and genotyped using genotyping by sequencing (GBS). The main objective of this study was to identify resistance-associated single nucleotide polymorphism (SNP) markers from the cultivar Whale against the P. effusa race 16. Results Association analysis conducted using GBS markers identified six significant SNPs (S3_658,306, S3_692697, S3_1050601, S3_1227787, S3_1227802, S3_1231197). The downy mildew resistance locus from cultivar Whale was mapped to a 0.57 Mb region on chromosome 3, including four disease resistance candidate genes (Spo12736, Spo12784, Spo12908, and Spo12821) within 2.69–11.28 Kb of the peak SNP. Conclusions Genomewide association analysis approach was used to map the P. effusa race 16 resistance loci and identify associated SNP markers and the candidate genes. The results from this study could be valuable in understanding the genetic basis of downy mildew resistance, and the SNP marker will be useful in spinach breeding to select resistant lines.

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Mutants of downy mildew resistance in Lactuca sativa (lettuce).

Genetics ◽

10.1093/genetics/137.3.867 ◽

1994 ◽

Vol 137 (3) ◽

pp. 867-874

Author(s):

P A Okubara ◽

P A Anderson ◽

O E Ochoa ◽

R W Michelmore

Keyword(s):

Molecular Marker ◽

Downy Mildew ◽

Genomic Dna ◽

Spontaneous Mutation ◽

Multigene Families ◽

Downy Mildew Resistance ◽

Bremia Lactucae ◽

Wild Type ◽

Mildew Resistance ◽

Recessive Mutations

Abstract As part of our investigation of disease resistance in lettuce, we generated mutants that have lost resistance to Bremia lactucae, the casual fungus of downy mildew. Using a rapid and reliable screen, we identified 16 distinct mutants of Latuca sativa that have lost activity of one of four different downy mildew resistance genes (Dm). In all mutants, only a single Dm specificity was affected. Genetic analysis indicated that the lesions segregated as single, recessive mutations at the Dm loci. Dm3 was inactivated in nine of the mutants. One of five Dm 1 mutants was selected from a population of untreated seeds and therefore carried a spontaneous mutation. All other Dm1, Dm3, Dm5/8 and Dm7 mutants were derived from gamma- or fast neutron-irradiated seed. In two separate Dm 1 mutants and in each of the eight Dm3 mutants analyzed, at least one closely linked molecular marker was absent. Also, high molecular weight genomic DNA fragments that hybridized to a tightly linked molecular marker in wild type were either missing entirely or were truncated in two of the Dm3 mutants, providing additional evidence that deletions had occurred in these mutants. Absence of mutations at loci epistatic to the Dm genes suggested that such loci were either members of multigene families, were critical for plant survival, or encoded components of duplicated pathways for resistance; alternatively, the genes determining downy mildew resistance might be limited to the Dm loci.

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