SMART – Sunflower Mutant population And Reverse genetic Tool for crop improvement

Abstract

BackgroundSunflower (Helianthus annuus L.) is an important oilseed crop grown widely in various areas of the world. Classical genetic studies have been extensively undertaken for the improvement of this particular oilseed crop. Pertaining to this endeavor, we developed a “chemically induced mutated genetic resource for detecting SNP by TILLING” in sunflower to create new traits.ResultsTo optimize the EMS mutagenesis, we first conducted a “kill curve” analysis with a range of EMS dose from 0.5% to 3%. Based on the observed germination rate, a 50% survival rate i.e. LD50, treatment with 0.6% EMS for 8 hours was chosen to generate 5,000 M2 populations, out of which, 4,763 M3 plants with fertile seed set. Phenotypic characterization of the 5,000 M2 mutagenised lines were undertaken to assess the mutagenesis quality and to identify traits of interest. In the M2 population, about 1.1% of the plants showed phenotypic variations. The sunflower TILLING platform was setup using Endo-1-nuclease as mismatch detection system coupled with an eight fold DNA pooling strategy. As proof-of-concept, we screened the M2 population for induced mutations in two genes related to fatty acid biosynthesis, FatA an acyl-ACP thioesterase and SAD the stearoyl-ACP desaturase and identified a total of 26 mutations.ConclusionBased on the TILLING of FatA and SAD genes, we calculated the overall mutation rate to one mutation every 480 kb, similar to other report for this crop so far. As sunflower is a plant model for seed oil biosynthesis, we anticipate that the developed genetic resource will be a useful tool to identify novel traits for sunflower crop improvement.

Kill curve analysis and response of first generation Capsicum annuum L. B12 cultivar to ethyl methane sulfonate

“…Further, germination may be inhibited due to the toxic nature of the mutagen (Kumar et al, 2013), damage to cell constituents at the molecular level, or altered enzyme activity (Khan and Goyal, 2009). As expected, the highest germination ratio was observed with the control treatment, irrespective of all presoaking treatments.…”

Perspectives of Breeding for Altering Sunflower Oil Quality to Obtain Novel Oils

“…salad oil) will require a reduction of saturated fatty acids and enhancement of the vitamin E (alphatocopherol) content of the oil. Research is mainly focused on (i) the production of more stable sunflower oils for biolubrication and (ii) the increase of healthy substitutes for food industry (Kumar et al, 2013).…”

“…The modification by genetic transformation of fatty acids composition of sunflower seed oil can also be prospected in a near future. To address the needs of the confectionery industry for saturated fatty acids, high stearic acid content oils have been developed mainly by genetic modification of the FatA stearoyl-ACP thioesterase and the SAD stearoyl-ACP desaturase (Kumar et al, 2013). Additive type of gene action controls the traits oleic acid content and linoleic acid content.…”

pENCODE: A Plant Encyclopedia of DNA Elements

“…In many cases, having epigenomic maps would facilitate a more rapid identification of these causal variants by providing an additional layer of information, especially in species that have large genomes. To enable hypothesis testing of predicted causal variants, mutant strains provide a vital resource, and fortunately there are already numerous projects aimed at creating large mutant populations of diverse plant species using T-DNA, transposon tagging, or TILLING mutagenesis (6, 14, 19, 26, 27, 30, 69, 93, 100, 104, 107, 123, 131). These mutant populations, in combination with results from pENCODE, will be invaluable for identifying trait-associated sequence variants.…”