In order to enlarge the potential resources of drought-tolerant peanuts, we conducted invitro mutagenesis with Pingyangmycin (PYM) as the mutagen as well as directed screeningon a medium supplemented with Hydroxyproline (HYP). After being extracted from matureseeds (cv. Huayu 20), the embryonic leaflets were cultured on somatic embryogenesis-inductionmedium with 4 mg/L PYM and the generated embryos were successively transferredto a germination medium with 4 and then 8 mmol/L HYP to screen HYP-tolerantplantlets. After that, these plantlets were grafted and transplanted to the experimental field.In the next generation, all seeds were sown in the field, and phenotype variation and traitsegregation can be observed in most of the offspring (M2 generation). The M3 generation individualswere subjected to drought stress at the seedling stages. The activities of SOD andPOD were substantially increased in eight offspring of 11 HYP-tolerant, regenerated plantsthan in their mutagenic parents. To determine the correlation between mutant phenotypesand genomic modification, we carried out a comparison of the DNA polymorphisms betweenthe mutagenic parents and 13 M3 generation individuals from different HYP-tolerant,regenerated plants with SSR primers. Results showed that most mutants and parent plantshad signs of polymorphisms. Under drought stress, some M3 generation individuals of 10original HYP-tolerant, regenerated plants produced more pods than the mutagenic parent;twenty individuals among them produced >60 g pods/plant. M4-generation seeds were tested
for quality characteristics by Near Infrared Spectroscopy (NIS) and nine individuals with
higher protein content (>30%) and 21 individuals with higher oil content (>58%) were
screened. We concluded that the use of PYM-based in vitro mutagenesis in combination
with directed screening with HYP is effective for the creation of potential drought-tolerant
mutants of peanut.
PLOS ONE | DOI:10.1371/journal.pone.0119240 March 31, 2015 1 /
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