Abstract
Soil salinity is a common abiotic stress affecting crop productivity. To identify favorable alleles from wild rice (Oryza rufipogon Griff.) that enhance salinity tolerance of rice (O. sativa L.), a set of introgression lines (ILs) were developed. The ILs were derived from an O. rufipogon accession collected from Chaling (Hunan Province, China) as the donor, and a widely grown O. sativa indica cultivar 93-11 as the recipient. Through evaluating the salt tolerance of 285 ILs at the seedling stage, a total of 10 quantitative trait loci (QTLs) related to salt tolerance were identified on chromosomes 1, 5, 7 and 9–12, with individual QTLs explaining 2–8% of phenotypic variance. The O. rufipogon-derived alleles at four QTLs improved salt tolerance in the 93-11 background. At the same time, a salt-tolerant IL, 9L136, was identified and characterized. Compared with the recipient parent 93-11, a total of 1,391 differentially expressed genes (DEGs) were detected specifically in 9L136 between salt stress and normal condition through genome-wide expression analysis. Of these, four DEGs located in the QTL regions carried by 9L136, suggesting that the four genes might be candidates associated with salt tolerance. Both the highly salt-tolerant ILs and the favorable O. rufipogon-derived QTLs identified in the present study will provide new genetic resources for improving the resistance of cultivated rice against salinity stress using molecular breeding strategies in the future.
Highlights
Soil salinity is one of the most common abiotic stresses affecting crop growth and productivity worldwide (Hoang et al, 2016)
To identify O. rufipogon-derived favorable alleles associated with salt tolerance, we investigated both salt tolerance score (STS) and survival rate of 285 introgression lines (ILs) and the recurrent parent 93-11 under 125 mM NaCl treatment
Phenotypic measurement showed that the frequency distributions of the two traits in the IL population accorded with the normal distribution, and both STS and the survival rate of the recurrent parent 93-11 (1.07 and 43%) were lower than the means for ILs (1.81 and 54%) at the seedling stage (Figure 1 and Table 1)
Summary
Soil salinity is one of the most common abiotic stresses affecting crop growth and productivity worldwide (Hoang et al, 2016). It is estimated that 20% of the total cultivated and 33% of irrigated agricultural land are affected by salinity (Epstein et al, 1980). Many adaptation and mitigation strategies are required for crops to cope with the impacts of salinity. These strategies are cost intensive and time-consuming. Compared with improving saline soil, enhancing resistance of crop plants against salinity stress by breeding and genetic manipulation is an effective and low-cost approach. Rice (Oryza sativa L.), one of the most important food crops
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