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摘要: Brassica napus (Parra et al., 1990). Furthermore, a correlation between low-temperature-induced anthocyanin synthesis and the accumulation of PAL and CHS mRNA has recently been demonstrated in maize (Christie et al., 1994). In Arabidopsis thaliana, a chilling-tolerant plant able to acclimate to the cold (Gilmour et al., 1988), cold stress also causes the accumulation of anthocyanins in leaves and stems. To understand how this accumulation is regulated and to further elucidate the role of anthocyanins during CA in Arabidopsis, we analyzed the expression of PAL and CHS genes during low-temperature exposure. The results indicate that low-temperature exposure increases the steady-state levels of PAL and CHS mRNAs only in the light. Furthermore, using transgenic Arabidopsis plants containing the uidA gene encoding the GUS of Escherickia coli under the control of the PALZ promoter, we demonstrate that the accumulation of PALZ mRNA is transcriptionally regulated. Histochemical staining of GUS activity in cross-sections of low-temperature-exposed stems revealed that the PALl promoter is preferentially activated in cortical cells, which are photosynthetically active and accumulate anthocyanins during CA. Moreover, we show that the accumulation of CHS mRNA by other stimuli, such as bacterial infiltration, also requires the presence of light, suggesting that light may be indispensable for CHS mRNA accumulation in Arabidopsis. Finally, we demonstrate thatAbbreviations: CA, cold acclimation; CHS, chalcone synthase; PAL, phenylalanine ammonia-lyase. www. plant. org on February 8, 2016-Published by www. plantphysiol. org …