Complete resistance to powdery mildew and partial resistance to downy mildew in a Cucumis hystrix introgression line of cucumber were controlled by a co-localized locus
Key message A single recessive gene for complete resistance to powdery mildew and a major-effect QTL for partial resistance to downy mildew were co-localized in a Cucumis hystrix introgression line of cucumber.
Downy mildew (DM) and powdery mildew (PM) are two major foliar diseases in cucumber. DM resistance (DMR) and PM resistance (PMR) may share common components; however, the genetic relationship between them remains unclear. IL52, a Cucumis hystrix introgression line of cucumber which has been reported to possess DMR, was recently identified to exhibit PMR as well. In this study, a single recessive gene pm for PMR was mapped to an approximately 468-kb region on chromosome 5 with 155 recombinant inbred lines (RILs) and 193 F2 plants derived from the cross between a susceptible line ‘changchunmici’ and IL52. Interestingly, pm was co-localized with the major-effect DMR QTL dm5.2 confirmed by combining linkage analysis and BSA-seq, which was consistent with the observed linkage of DMR and PMR in IL52. Further, phenotype–genotype correlation analysis of DMR and PMR in the RILs indicated that the co-localized locus pm/dm5.2 confers complete resistance to PM and partial resistance to DM. Seven candidate genes for DMR were identified within dm5.2 by BSA-seq analysis, of which Csa5M622800.1, Csa5M622830.1 and Csa5M623490.1 were also the same candidate genes for PMR. A single nucleotide polymorphism that is present in the 3ˊ untranslated region (3′UTR) of Csa5M622830.1 co-segregated perfectly with PMR. The GATA transcriptional factor gene Csa5M622830.1 may be a likely candidate gene for DMR and PMR. This study has provided a clear evidence for the relationship between DMR and PMR in IL52 and sheds new light on the potential value of IL52 for cucumber DMR and PMR breeding program.
The authors thank Martin Kagiki Njogu (Department of Horticulture, College of Horticulture, Nanjing Agricultural University, Nanjing, China) for critical reading of the manuscript. This research was supported by National Natural Science Foundation of China (Key Program, No. 31430075), Special Fund for Agro-Scientific Research in the Public Interest (No. 201403032), National Key Research and Development Program of China (2016YFD0101705-5), National Key Research and Development Program of China (2016YFD0100204-25), National Natural Science Foundation of China (No. 31672168), Independent Innovation of Agricultural Science and Technology of Jiangsu Province (CX(17)3016), Fundamental Research Funds for the Central Universities (No. KYZ201828).
Compliance with ethical standards
Conflict of interest
The authors declare no conflict of interest.
The experiments were performed in accordance with all relevant Chinese laws.
- Abe A, Kosugi S, Yoshida K et al (2012) Genome sequencing reveals agronomically important loci in rice using MutMap. Nat Biotechnol 119:313–327Google Scholar
- An Y, Han X, Tang X et al (2014) Poplar GATA transcription factor PdGNC is capable of regulating chloroplast ultrastructure, photosynthesis, and vegetative growth in Arabidopsis under varying nitrogen levels. Plant Cell Tissue Organ Cult 30:174–178Google Scholar
- Bai Z, Yuan X, Cai R et al (2008) QTL analysis of downy mildew resistance in cucumber. Prog Nat Sci 18:706–710 (in Chinese) Google Scholar
- Caldwell D, Chan E, de Vries J et al (2011) Methods and compositions for identifying downy mildew resistant cucumber plants. United States patent US 2011/0126309 A1Google Scholar
- Cao Q (2006) Research on cucumber alien translocation line possessing resistance to downy mildew and its application in cucumber breeding. Dissertation, Nanjing Agricultural University (in Chinese)Google Scholar
- de Ruiter W, Hofstede R, de Vries J, van den Heuvel H (2008) Combining QTL for resistance to CYSDV and powdery mildew in a single cucumber line. In: Proceedings of 9th EUCARPIA meeting on genetics and breeding of Cucurbitaceae (Pitrat M, ed), INRA, Avignon (France), 21–24 May, pp 181–188Google Scholar
- Dijkhuizen A, Kennard WC, Havey MJ et al (1996) RFLP variation and genetic relationships in cultivated cucumber. Euphytica 90:79–87Google Scholar
- Ding G, Qin Z, Zhou X et al (2007) RAPD and SCAR markers linked to downy mildew resistance genes in cucumber. Acta Bot Boreali-Occident Sin 27:1747–1751 (in Chinese) Google Scholar
- Epps W, Barnes W (1952) The increased susceptibility of the Palmetto cucumber to downy mildew in South Carolina. Plant Dis Rep 36:14–15Google Scholar
- Jenkins SF, Wehner TC (1983) A system for the measurement of foliar diseases of cucumber. Cucurbit Genet Coop Rep 6:10–12Google Scholar
- Kooistra E (1968) Powdery mildew resistance in cucumber. Euphytica 17:236–244Google Scholar
- Nie J, Wang Y, He H et al (2015b) Loss-of-function mutations in CsMLO1 confer durable powdery mildew resistance in cucumber (Cucumis sativus L.). Front. Plant Sci 6:1155Google Scholar
- Olaya G, Kuhn P, Hert A (2009) Fungicide resistance in cucurbit downy mildew. Phytopathology 9:S171Google Scholar
- Roque A, Adsuar J (1939) New cucumber varieties resistant to the downy mildew. In: Annual report agricultural experiment station of Puerto Rico fiscal year 1937–1938, pp 45–46Google Scholar
- Smith P (1948) Powdery mildew resistance in cucumber. Phytopathology 38:1027–1028Google Scholar
- Van Ooijen JW (2006) Joinmap 4.0. Software for the calculation of genetic linkage maps in experimental populations. Kyazma BV, Wagenigen, p 63Google Scholar
- VandenLangenberg KM (2015) Studies on downy mildew resistance in cucumber (Cucumis sativus L.). Dissertation, North Carolina State UniversityGoogle Scholar
- Wang S, Basten CJ, Zeng ZB (2007) Windows QTL cartographer 2.5. Raleigh, NC: Department of Statistics, North Carolina State University http://statgen.ncsu.edu/qtlcart/WQTLCart.htm
- Weng Y, Johnson S, Staub JE et al (2010) An extended microsatellite genetic map of cucumber, Cucumis sativus L. HortScience 45:880–886Google Scholar
- Zhang H, Wang Z, Mao A et al (2008) SSR markers linked to the resistant gene of cucumber powdery mildew. Acta Agric Boreali-Sin 23:77–80 (in Chinese) Google Scholar
- Zhang S, Liu M, Miao H et al (2011) QTL mapping of resistance genes to powdery mildew in cucumber. Sci Agric Sin 44:3584–3593Google Scholar