Metabolomics combined with physiology and transcriptomics reveals how Citrus grandis leaves cope with copper-toxicity

Adaptive Responses of Citrus grandis Leaves to Copper Toxicity Revealed by RNA-Seq and Physiology

“…Here, we identified one upregulated and seven downregulated GSTs in LCGSEC ( Table S12 ). This agrees with our report that LCGSEC had increased accumulation of GSH [ 50 ]. However, Leng et al [ 34 ] identified 27 upregulated and three downregulated GSTs in grape leaves exposed to Cu-toxicity.…”

“…Cu chelators play a role in internal accumulation mechanisms, in which the complexation of Cu can increase Cu immobilization in organelles such as vacuole or cell wall. The present findings and our recent work demonstrated that Cu-toxicity increased the accumulation of PCs, MTs ( Figure 2 ), TRP ( Figure 5 ), GSH, total phenolics and lignin [ 50 ] in C. grandis leaves, implying that internal accumulation mechanisms played a role in Cu-tolerance of C. grandis leaves.…”

“…Additionally, we obtained three downregulated and five upregulated genes related to cell redox homeostasis (GO:0045454) in LCGSEC. In conclusion, some genes correlated to thermal dissipation, photorespiration, ROS scavenging and cell redox homeostasis ( Table S12 ) and the levels of some antioxidants such as PCs, MTs, TRP ( Figure 2 and Figure 5 ), GSH and total phenolics [ 50 ] were upregulated in LCGSEC, but they could not sufficiently protect these leaves from oxidative damage, because MDA level [ 50 ] and electrolyte leakage [ 2 ] were increased in LCGSEC.…”

“…ABA has been suggested to have a positive and synergistic relationship with the biosynthesis of GSH and PCs [ 81 ]. Cu-toxicity-induced increase of ABA concentration might improve the biosynthesis of GSH and PCs, as indicated by increased accumulation of GSH [ 50 ] and PCs ( Figure 5 ) in LCGSEC. Zehra et al [ 26 ] reported that ABA alleviated Cu-toxicity-induced oxidative damage in A. annua leaves by reducing ROS production.…”

“…Plant culture and Cu treatments were carried out as described by Li et al [ 2 ] and Huang et al [ 50 ]. Briefly, ~13-week-old ‘Shatian’ pummelo ( Citrus grandis (L.) Osbeck) seedlings grown in 6 L pots (two plants pot −1 ) containing sand in a greenhouse with natural photoperiod at Fujian Agriculture and Forestry University, Fuzhou (26°5′ N, 119°14′ E) with annual average sunshine hours, temperature and relative humidity of ~1600 h, 20 °C and 76%, respectively [ 84 ], were irrigated 6 times weekly for 6 months with freshly prepared nutrition solution at a Cu level of 0.5 or 400 μM from CuCl 2 until there was nutrient solution leaking out of the small hole at the bottom of the pot (~500 mL).…”