Mapping Cloning Of Rice White Stripe Leaf Mutant Wdl1 Preliminary Analysis Of Functions

In this study,white-leaf leaf mutant wdl1(white dragon leaf one)and wild-type Longgeng11 were used as test materials.Leaf photosynthetic characteristics,chloroplast ultrastructure and important agronomic traits were tested.And mutation trait genes were located and cloned.The results of the study are as follows:1.Compared with Longgeng11,the stems and leaves of the mutant wdl1 showed white stripes throughout the growth period,white stripes on 1-3 leaves were weaker,and 4-5 leaves became heavier until mature.The chlorophyll content(SPAD value)of the mutant wdl1 was lower than Longgeng11 in the 3-8 leaf stage,and the contents of chlorophyll b,carotenoids and total chlorophyll were significantly reduced by 84.66%,91.78% and 93.63% respectively was not changed.While the content of chlorophyll a remained basically unchanged.The net photosynthetic rate,stomatal conductance,and transpiration rate of mutant wdl1 were reduced by 17.53%,2.19% and 17.99% respectively than Longgeng11,and the intercellular CO2 concentration was increased by 4.49%.The initial fluorescence of the mutant wdl1 was reduced by 24.79% than Longgeng11,and the maximum photochemical efficiency and electron transfer rate were increased by 1.21% and 33.36% than Longgeng11,respectively.The non-photochemical quenching coefficient was not changed.Through the analysis of the ultrastructure of chloroplasts,the number of chloroplasts in the mesophyll cells of the mutant wdl1 was decreased and the number of starch granules was significantly increased compared with the Longgeng11.2.The plant height of mutant wdl1 was significantly increased,and effective tillering was significantly reduced compared with Longgeng11.There was no significant difference in flag leaf length and flag leaf width.The ear traits of mutant wdl1 were not significantly different from Longjing11.The processing quality of mutant wdl1 was not significantly different from Longjing11.In the appearance quality,the chalkiness of the mutant wdl1 was significantly increased,and the difference with Longgeng11 reached significant level.In the RVA spectral characteristic values,the peak viscosity,hot slurry viscosity,disintegration value,cold paste viscosity,and recovery value of the mutant wdl1 were all significantly reduced than Longgeng11,and the peak time and duration were slightly increased.The taste quality of the mutant wdl1 was not significantly different from the wild type.3.The mutant wdl1 was used to hybridize with indica rice IRAT10 and indica rice 618 B respectively.F1 was self-introduced and F2 population was derived.The ratio of leaf color separation in F2 generation was investigated.Chi-square test showed that normal leaf color and white striped leaf color in F2 population.The segregation ratio of the strains satisfies the 3:1 separation,indicating that the wdl1 gene controlled the white striped color is a pair of recessive nuclear genes.By map-based cloning,the gene wdl1 is located on the short arm of chromosome 1 with a physical distance about 440.9 kb.There are 72 candidate OFRs in the interval.4.Through the analysis and prediction of the candidate OFRs,it was found that the HD domain encoded by the gene LOC_Os01g01920 may participate in photoreceptor regulation and play a role in signal transduction.Sequencing of the LOC_Os01g01920 gene revealed a one-base substitution(C?T)in the exon region.This base mutation caused amino acid changes,which in changed leaf color.