Differential responses to UV-B irradiation of three near isogenic lines carrying different purple leaf genes for anthocyanin accumulation in rice (Oryza sativa L.)

We produced near isogenic lines (NILs) for three purple leaf genes, Pl, Pl( w) and Pl(i) of rice with a genetic background of T-65 to characterize each allele, Three NILs each had characteristic tissue-specific anthocyanin pig mentation. T-65 Pl(w) was newly found to make the root purple when the root was exposed to light. To explore the inducible characteristics of the thre e genes, we examined the responses of the three NILs to UV-B irradiation, A lthough the accumulation of anthocyanin increased in all NILs with the incr ease in the intensity of UV-B irradiation, we observed differential respons es for the accumulation of anthocyanin in the NILs: T-65 Pl(i) accumulated the largest amounts of anthocyanin under meal; and intermediate: intensity of UV-B, though this NIL, reduced anthocyanin accumulation under a high int ensity of UV-B. T-65 Pl or Pl(w) increased anthocyanin accumulation with in creasing intensity of UV-B, Anthocyanin accumulation of the Pl NIL was high er than that of the Pl(w) NIL under each intensity of UV-B. In addition, th e total biomass of ail the irradiated NILs decreased with the increasing do se of UV-B irradiation and the decrease was negatively correlated with the increase in anthocyanin accumulation in the dose range of UV-B irradiation.