CsERF53 is essential for ABA-mediated carotenoid biosynthesis in citrus.
(A)CsERF110 expression in citrus fruit and calli under ABA treatment.
(B)In vivo LUC complementation imaging of N. benthamiana leaves treated with water or ABA. A suspension of Agrobacterium GV3101 carrying ProCsERF53-LUC was injected into N. benthamiana leaves. Two days after injection, N. benthamiana leaves were treated with water or 100 μM ABA, and 24 h later, bioluminescence imaging was used to measure the luciferase activity of ProCsERF53.
(C–F) Stable transformation of CsERF53 in citrus calli. (C) Phenotypes. PH7-CsERF53 and RNAi-ERF53 indicate CsERF53 overexpression and RNA interference, respectively. PH7-Ev and RNAi are controls. Expression levels of CsERF53(D) and CsGGPPS, CsPSY, CsZEP, CsHYD, and CsNCED2(F) are shown. (E) Total carotenoid content (μg/g DW).
(G, H, and J) Transient expression of CsERF53 in citrus fruit. (G) Phenotypes. PK7-Ev and RNAi serve as controls. PK7-CsERF53 and RNAi-CsERF53 indicate CsERF53 overexpression and RNA interference, respectively. Scale bars, 2 cm. Transcript levels of CsERF53(H) and CsGGPPS, CsPSY, CsZEP, CsHYD, and CsNCED2(J) are shown.
(I) Total carotenoid content (μg/g DW). Data are presented as means ± SDs of three biological replicates. Asterisks indicate statistically significant differences determined by Student’s t test (∗p < 0.05; ∗∗p < 0.01; n.s., no significant difference).