Profiling microRNAs in Eucalyptus grandis reveals no mutual relationship between alterations in miR156 and miR172 expression and adventitious root induction during development
1 The Institute of Plant Sciences, Volcani Center, P.O. Box 6, Bet-Dagan 5025000, Israel
2 The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 7610001, Israel
3 Current address: Syngenta Seeds – R&D, Valle de Azapa Km 17, Arica, Chile
BMC Genomics 2014, 15:524 doi:10.1186/1471-2164-15-524Published: 25 June 2014
The change from juvenile to mature phase in woody plants is often accompanied by a gradual loss of rooting ability, as well as by reduced microRNA (miR) 156 and increased miR172 expression.
We characterized the population of miRNAs of Eucalyptus grandis and compared the gradual reduction in miR156 and increase in miR172 expression during development to the loss of rooting ability. Forty known and eight novel miRNAs were discovered and their predicted targets are listed. The expression pattern of nine miRNAs was determined during adventitious root formation in juvenile and mature cuttings. While the expression levels of miR156 and miR172 were inverse in juvenile and mature tissues, no mutual relationship was found between high miR156 expression and rooting ability, or high miR172 expression and loss of rooting ability. This is shown both in E. grandis and in E. brachyphylla, in which explants that underwent rejuvenation in tissue culture conditions were also examined.
It is suggested that in these Eucalyptus species, there is no correlation between the switch of miR156 with miR172 expression in the stems and the loss of rooting ability.