DFR and PAL gene transcription and their correlation with anthocyanin accumulation in Rhodomyrtus tomentosa (Aiton.) Hassk.

Abstract

Abstract Objectives Rhodomyrtus tomentosa (Aiton.) Hassk. (R. tomentosa) is rich in nutrients and has multiple pharmacological applications. Anthocyanins confer color to the flowers and berries of R. tomentosa and provide protection against photodamage. The dihydroflavonol 4-reductase gene (DFR) and phenylalanine ammonialyase gene (PAL) are crucial for anthocyanin synthesis. Methods DFR and PAL transcript levels and anthocyanin content in the pigmented organs of R. tomentosa were investigated through qRT-PCR analysis and spectrophotometry, respectively. The glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene was selected as the reference gene for the normalization of DFR and PAL transcript levels. Results Transcript levels of DFR and PAL were higher in organs with vigorous metabolism than those in senescent organs. DFR and PAL transcript levels were up-regulated during the initial and middle-maturity periods of fruit. These expression patterns are consistent with fruit color development. The highest transcript levels of PAL and DFR were observed during the middle-maturity period or the red-fruit period. Conclusion During the late maturity period of R. tomentosa fruit, the transcript levels of the two genes were down-regulated even though anthocyanins were continuously accumulated, which was different from the accumulation of anthocyanins in some late mature fruits.