Inhibition of red chlorophyll catabolite reductase improved chlorophyll and carotenoid synthesis in tobacco
2022
Dong, Chen | Zhang, Mei | Wei, Fang | Guo, Yushuang | Qin, Lili | Wei, Pan | Wang, Yubo | Jin, Lifeng | Song, Weina | Sun, Tao | Li, Feng | Wang, Ran
Red chlorophyll catabolite reductase (RCCR) is essential in catalyzing chlorophyll degradation in plants. Our study illustrated that the amino acid sequence, secondary structure, trans-membrane sequence and motif of tobacco RCCR were highly conserved. Although virus-induced gene silencing of RCCR had only a slight effect on the phenotype of leaves in Nicotiana benthamiana, it resulted in a significant increase in chlorophyll and carotenoid content. Moreover, both NbCLH and NbPAO encoding enzymes in chlorophyll degradation pathway were decreased when NbRCCR1 was silenced. However, the expression of key genes NbPSY1, NbLCYB and NbCRTISO in carotenoids biosynthesis was increased. Beside this, the genes encoding the proteins of LHC II (NbLHCB2, NbLHCB3 and NbLHCB6) were down-regulated. Results of BN-PAGE showed that the accumulation of Phytosystem II (PS II) supercomplex and LHC II complex in leaves of RCCR silenced tobacco was significantly less than wild type. Additionally, both NPQ and reactive oxygen species were increased in RCCR silenced tobacco under high light stress. Our results illustrated that RCCR might participate in regulating the biosynthesis of chlorophyll and carotenoids in higher plants.
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