Silencing of the FRO1 gene and its effects on iron partition in Nicotiana benthamiana

• Published in: Plant physiology and biochemistry Vol. 114; pp. 111 - 118
• Main Authors: Gama, Florinda, Saavedra, Teresa, Dandlen, Susana, de Varennes, Amarilis, Correia, Pedro J., Pestana, Maribela, Nolasco, Gustavo
• Format: Journal Article
• Language: English
• Published: France Elsevier Masson SAS 01.05.2017
• Subjects: Chlorophyll - metabolism; Ferric reductase oxidase gene; Ferric-chelate reductase; Gene Expression Regulation, Plant; Gene Silencing; Genes, Plant; Hydroponics; Iron - metabolism; Iron deficiency; Nicotiana - genetics; Nicotiana - metabolism; Plant Leaves - physiology; Plant Viruses - genetics; Tobacco rattle virus; Virus-induced gene silencing; BPDS; FRO; Chl; SPAD; Ferric reductase oxidase gene; Iron deficiency; EDTA; Virus-induced gene silencing; FW; EDDHA; DW; Ferric-chelate reductase; FCR; VIGS; TRV; MES; Tobacco rattle virus; EC; Fe
• ISSN: 0981-9428; 1873-2690
• DOI: 10.1016/j.plaphy.2017.03.004

To evaluate the dynamic role of the ferric-chelate reductase enzyme (FCR) and to identify possible pathways of regulation of its activity in different plant organs an investigation was conducted by virus-induced gene silencing (VIGS) using tobacco rattle virus (TRV) to silence the ferric reductase oxidase gene (FRO1) that encodes the FCR enzyme. Half of Nicotiana benthamiana plants received the VIGS vector and the rest remained as control. Four treatments were imposed: two levels of Fe in the nutrient solution (0 or 2.5 μM of Fe), each one with silenced or non-silenced (VIGS-0; VIGS-2.5) plants. Plants grown without iron (0; VIGS-0) developed typical symptoms of iron deficiency in the youngest leaves. To prove that FRO1 silencing had occurred, resupply of Fe (R) was done by adding 2.5 μM of Fe to the nutrient solution in a subset of chlorotic plants (0-R; VIGS-R). Twelve days after resupply, 0-R plants had recovered from Fe deficiency while plants containing the VIGS vector (VIGS-R) remained chlorotic and both FRO1 gene expression and FCR activity were considerably reduced, consequently preventing Fe uptake. With the VIGS technique we were able to silence the FRO1 gene in N. benthamiana and point out its importance in chlorophyll synthesis and Fe partition. •Chlorotic N. benthamiana plants totally recover when Fe is supplied to the nutrient solution.•Chlorotic FRO1 silenced N. benthamiana plants do not recover when Fe is supplied to the nutrient solution.•FRO1 expression and F-CR activity were considerably reduced.•FRO1 gene in N. benthamiana plants is important for regulating Fe partition.