Long-distance movement and differential targeting of microRNA399s.
We have previously demonstrated that miR399s control phosphate (Pi) homeostasis by regulating the expression of a ubiquitin-conjugating E2 enzyme (UBC24/PHO2) in Arabidopsis. Changes in miR399-dependent PHO2 gene expression modulate Pi uptake, allocation and remobilization. More recently, we provided evidence that miR399s are able to move in the phloem stream and across grafting junctions from the scions overexpressing miR399 to the wild-type rootstocks. Movement of miR399s serves as a long-distance signal to report and balance the Pi status between shoots and roots. Of note, results from grafting experiments indicate that miR399b is less efficient in cleaving the PHO2 mRNA than is miR399f, despite the similar mobility of the two miR399s. We propose that nucleotide 13 of miR399s, which gives rise to the sequence variation among different miR399 species, could be involved in regulating the abundance of PHO2 mRNA through sequence complementarity to the target sequences of PHO2 mRNA and mimicking target sequence of At4/IPS1 noncoding RNAs.
Lin
Shu-I
SI
Graduate Institute of Life Sciences; National Defense Medical Center; and Agricultural Biotechnology Research Center; Academia Sinica; Taipei, Taiwan, Republic of China.
Chiou
Tzyy-Jen
TJ
Plant Cell. 2004 Aug;16(8):1979-2000
15258266
Plant Physiol. 2006 Jul;141(3):1000-11
16679417
Dev Biol. 2006 Jan 1;289(1):3-16
16325172
Nat Genet. 2007 Aug;39(8):1033-7
17643101
Nat Genet. 2006 Jun;38 Suppl:S31-6
16736022
Trends Plant Sci. 2007 Jul;12(7):301-9
17573231
Planta. 1998 Jun;205(2):251-6
9637070
Plant Physiol. 2008 May;147(1):58-62
18443104
Annu Rev Plant Biol. 2006;57:19-53
16669754
Curr Biol. 2005 Nov 22;15(22):2038-43
16303564
Plant Cell. 2006 Feb;18(2):412-21
16387831
Plant Cell Environ. 2007 Mar;30(3):323-332
17263777
Plant Physiol. 1995 Jan;107(1):207-213
12228355
Plant Physiol. 2008 Jun;147(2):732-46
18390805
Plant J. 2008 Mar;53(5):739-49
18005229
Plant Physiol. 2006 Jul;141(3):988-99
16679424
Plant J. 2008 Mar;53(5):731-8
17988220