Identification of a gene controlling variation in the salt tolerance of rapeseed (Brassica napus L.).
By genome-wide association study, QTLs for salt tolerance in rapeseed were detected, and a TSN1 ortholog was identified as a candidate gene responsible for genetic variation in cultivars. Dissecting the genomic regions governing abiotic stress tolerance is necessary for marker-assisted breeding to produce elite breeding lines. In this study, a world-wide collection of rapeseed was evaluated for salt tolerance. These rapeseed accessions showed a large variation for salt tolerance index ranging from 0.311 to 0.999. Although no significant correlation between salt tolerance and Na(+) content was observed, there was a significant negative correlation between shoot biomass production under a control condition and salt tolerance. These rapeseed accessions were genotyped by DArTseq for a total of 51,109 genetic markers, which were aligned with 'pseudomolecules' representative of the genome of rapeseed to locate their hypothetical order for association mapping. A total of 62 QTLs for salt tolerance, shoot biomass, and ion-homeostasis-related traits were identified by association mapping using both the P and Q+K models. Candidate genes located within the QTL regions were also shortlisted. Sequence analysis showed many polymorphisms for BnaaTSN1. Three of them in the coding region resulting in a premature stop codon or frameshift were found in most of the sensitive lines. Loss-of-function mutations showed a significant association with salt tolerance in B. napus.
Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori Amamiyamachi, Aoba-ku, Sendai, Miyagi, 981-8555, Japan, huiyee1@yahoo.com.
Hui-Yee
HY
Yong
Chunlei
C
Wang
Ian
I
Bancroft
Feng
F
Li
Xiaoming
X
Wu
Hiroyasu
H
Kitashiba
Takeshi
T
Nishio
D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D018533:Biomass; D029688:Brassica napus / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development / Q000502:physiology*; D002874:Chromosome Mapping; D060146:Ecotype; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D056726:Genetic Association Studies; D005819:Genetic Markers; D014644:Genetic Variation; D005828:Genetics, Population; D015810:Linkage Disequilibrium / Q000235:genetics; D008969:Molecular Sequence Data; D010641:Phenotype; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism; D018520:Plant Shoots / Q000187:drug effects / Q000378:metabolism; D040641:Quantitative Trait Loci / Q000235:genetics; D019655:Quantitative Trait, Heritable; D055049:Salt Tolerance / Q000187:drug effects / Q000235:genetics*; D012964:Sodium / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics
D005819:Genetic Markers; D012965:Sodium Chloride; D012964:Sodium