STAYGREEN (CsSGR) is a candidate for the anthracnose (Colletotrichum orbiculare) resistance locus cla in Gy14 cucumber
Key message Map-based cloning identified a candidate gene for resistance to the anthracnose fungal pathogen Colletotrichum orbiculare in cucumber, which reveals a novel function for the highly conserved STAYGREEN family genes for host disease resistance in plants. Colletotrichum orbiculare is a hemi...
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Published in | Theoretical and applied genetics Vol. 131; no. 7; pp. 1577 - 1587 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Berlin/Heidelberg
Springer Berlin Heidelberg
01.07.2018
Springer Nature B.V |
Subjects | |
Online Access | Get full text |
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Summary: | Key message
Map-based cloning identified a candidate gene for resistance to the anthracnose fungal pathogen
Colletotrichum orbiculare
in cucumber, which reveals a novel function for the highly conserved
STAYGREEN
family genes for host disease resistance in plants.
Colletotrichum orbiculare
is a hemibiotrophic fungal pathogen that causes anthracnose disease in cucumber and other cucurbit crops. No host resistance genes against the anthracnose pathogens have been cloned in crop plants. Here, we reported fine mapping and cloning of a resistance gene to the race 1 anthracnose pathogen in cucumber inbred lines Gy14 and WI 2757. Phenotypic and QTL analysis in multiple populations revealed that a single recessive gene,
cla
, was underlying anthracnose resistance in both lines, but WI2757 carried an additional minor-effect QTL. Fine mapping using 150 Gy14 × 9930 recombinant inbred lines and 1043
F
2
individuals delimited the
cla
locus into a 32 kb region in cucumber Chromosome 5 with three predicted genes. Multiple lines of evidence suggested that the cucumber
STAYGREEN
(
CsSGR
) gene is a candidate for the anthracnose resistance locus. A single nucleotide mutation in the third exon of
CsSGR
resulted in the substitution of Glutamine in 9930 to Arginine in Gy14 in CsSGR protein which seems responsible for the differential anthracnose inoculation responses between Gy14 and 9930. Quantitative real-time PCR analysis indicated that
CsSGR
was significantly upregulated upon anthracnose pathogen inoculation in the susceptible 9930, while its expression was much lower in the resistant Gy14. Investigation of allelic diversities in natural cucumber populations revealed that the resistance allele in almost all improved cultivars or breeding lines of the U.S. origin was derived from PI 197087. This work reveals an unknown function for the highly conserved
STAYGREEN
(
SGR
) family genes for host disease resistance in plants. |
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ISSN: | 0040-5752 1432-2242 |
DOI: | 10.1007/s00122-018-3099-1 |