Identification of miRNAs with potential roles in regulation of anther development and male-sterility in 7B-1 male-sterile tomato mutant.
BACKGROUND
The 7B-1 tomato line (Solanum lycopersicum cv. Rutgers) is a photoperiod-sensitive male-sterile mutant, with potential application in hybrid seed production. Small RNAs (sRNAs) in tomato have been mainly characterized in fruit development and ripening, but none have been studied with respect to flower development and regulation of male-sterility. Using sRNA sequencing, we identified miRNAs that are potentially involved in anther development and regulation of male-sterility in 7B-1 mutant.


RESULTS
Two sRNA libraries from 7B-1 and wild type (WT) anthers were sequenced and thirty two families of known miRNAs and 23 new miRNAs were identified in both libraries. MiR390, miR166, miR159 were up-regulated and miR530, miR167, miR164, miR396, miR168, miR393, miR8006 and two new miRNAs, miR#W and miR#M were down-regulated in 7B-1 anthers. Ta-siRNAs were not differentially expressed and likely not associated with 7B-1 male-sterility. miRNA targets with potential roles in anther development were validated using 5'-RACE. QPCR analysis showed differential expression of miRNA/target pairs of interest in anthers and stem of 7B-1, suggesting that they may regulate different biological processes in these tissues. Expression level of most miRNA/target pairs showed negative correlation, except for few. In situ hybridization showed predominant expression of miR159, GAMYBL1, PMEI and cystatin in tapetum, tetrads and microspores.


CONCLUSIONS
Overall, we identified miRNAs with potential roles in anther development and regulation of male-sterility in 7B-1. A number of new miRNAs were also identified from tomato for the first time. Our data could be used as a benchmark for future studies of the molecular mechanisms of male-sterility in other crops.
Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University and Institute of Experimental Botany AS CR, Šlechtitelů 11, CZ-78371, Olomouc, Czech Republic. vahid.omidvar@upol.cz.
Vahid
V
Omidvar
School of Computing Sciences, University of East Anglia, Norwich, NR4 7TJ, UK. i.mohorianu@uea.ac.uk.|School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, UK. i.mohorianu@uea.ac.uk.
Irina
I
Mohorianu
School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, UK. t.dalmay@uea.ac.uk.
Tamas
T
Dalmay
Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University and Institute of Experimental Botany AS CR, Šlechtitelů 11, CZ-78371, Olomouc, Czech Republic. martin.fellner@upol.cz.
Martin
M
Fellner
D035264:Flowers / Q000235:genetics / Q000502:physiology; D020869:Gene Expression Profiling; D018551:Solanum lycopersicum / Q000235:genetics* / Q000502:physiology; D035683:MicroRNAs / Q000235:genetics*; D051479:Plant Infertility / Q000235:genetics / Q000502:physiology
D035683:MicroRNAs