Comparative chlorophyll metabolic genes expression and response to dark stress of Ananas comosus var. bracteatus

摘要

Chlorophyll accumulation is essential for leaf colouration and photosynthesis function. This study analysed chlorophyll metabolism mechanism differences between the Slip regenerated White (SLW) and Green (SLG) and Tissue Cultured White (TCW) and Green (TCG) plants' leaf parts and their response to 30 d of dark stress. The TCG and TCW have higher chlorophyll content than the SLG and SLW, respectively. The chlorophyll biosynthesis and cycle genes, except Non-yellow colouring 1 (NYC1), are expressed apparently higher in green than in white leaf parts. The apparent up-regulation of Chlorophyllase (CLH) and down-regulation of 7-Hydroxymethyl Chlorophyll a reductase (HCAR) consequently caused the lower chlorophyll content in SLG compared to TCG. The down-regulation of CHLM and NOL may cause albino SLW. The apparent up-regulation of SGR, PAO, and PPH consequently caused the whitening of TCW. Under 30 days of dark stress, SLG and TCG leaves turned white. The down-regulation of Glutamyl-tRNA reductase 1 (HEMA1), Protochlorophyllide oxidoreductase (POR), and up-regulation of Stay Green (SGR) may result in SLG albino. The whitening of TCG is caused by the down-regulation of CHLM and NOL, also the up-regulation of Pheophorbide an oxygenase (PAO). The loss of green leaf colour affected PGK and PsaA expression, especially in TCG.