Abstract
The somatic embryogenic regeneration system is an ideal model system to study the regulation of early developmental processes and morphogenesis in gymnosperms. We have previously generated five larch (Larix leptolepis) LaMIR166a overexpression cell lines. The germination rates of mature somatic embryos in transgenic and wild-type (WT) lines were calculated and the results showed that overexpression of the miR166a precursor (LaMIR166a) markedly enhanced germination, especially in the a-3, a-4, and a-5 lines. The relative expression of LaMIR166a and miR166a in the LaMIR166a overexpression lines was higher than in the WT control line during the germination process, whereas the expression levels of LaHDZ31–34 increased markedly throughout germination, potentially as a result of feedback regulation of miR166. The effect of miR166a on auxin biosynthesis and signaling genes was also studied. During germination, mRNA levels of Nitrilase (LaNIT), Auxin response factor1 (LaARF1), and LaARF2 were markedly higher in LaMIR166a overexpressing lines. These results indicated that indole-3-acetic acid (IAA) synthesis is required for germination in L. leptolepis. Further exogenous application of IAA at different concentrations showed that 2 mg L−1 IAA clearly promoted germination, resulting in a 56% germination rate for L. leptolepis somatic embryos. This shows that IAA plays a vital role in controlling the germination ability of someatic embryos in L. leptolepis. Our results suggest that miR166a and LaHDZ31–34 have important roles in auxin biosynthesis and signaling during the germination of somatic embryos in L. leptolepis.
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Arnold SV, Bozhkov P, Clapham D, Dyachok J, Filonova L, Högberg KA, Ingouff M, Wiweger M (2004) Propagation of Norway spruce via somatic embryogenesis. Plant Cell Tissue Organ Culture 81:283–293
Ehrenreich IM, Purugganan MD (2008) Sequence variation of MicroRNAs and their binding sites in Arabidopsis. Plant Physiol 146:1974–1982
Ewald D, Kretzschmar U, Chen Y (1997) Continuous micropropagation of juvenile larch from different species via adventitious bud formation. Biol Plant 39:321–329
Huang D, Koh C, Feurtado JA, Tsang EW, Cutler AJ (2012) MicroRNAs and their putative targets in Brassica napus seed maturation. BMC Genom 14:1–25
Ji L, Liu X, YanJ, WangW, Yumul RE (2011) ARGONAUTE10 and ARGONAUTE1 regulate the termination of floral stem cells through two microRNAs in Arabidopsis. PLoS Genet 7:118–124
Jia X, Ding N, Fan W, Yan J, Gu Y, Tang X, Li R, Tang G (2015) Functional plasticity of miR165/166 in plant development revealed by small tandem target mimic. Plant Sci 233:11–21
Kidner CA, Martienssen RA (2005) The developmental role of microRNA in plants. Curr Opin Plant Biol 8:38–44
Krajňáková JK, Gömöry D, Häggman H (2008) Somatic embryogenesis in Greek fir. Can J For Res 38:760–769
Li S, Li W, Han SY, Yang WH, Qi L (2013a) Stage-specific regulation of four HD-ZIP III transcription factors during polar pattern formation in Larix leptolepis somatic embryos. Gene 522:177–183
Li W, Zhang S, Han S, Wu T, Zhang J, Qi L (2013b) Regulation of LaMYB33 by miR159 during maintenance of embryogenic potential and somatic embryo maturation in Larix kaempferi (Lamb.) Carr. Plant Cell Tiss Organ Cult 113:131–136
Li Z, Li S, Zhang L, Han S, Li W, Xu H, Yang W, Liu Y, Fan Y, Qi L (2016) Overexpression of miR166a inhibits cotyledon formation in somatic embryos and promotes lateral root development in seedlings of Larix leptolepis. Plant Cell Tiss Organ Cult doi:10.1007/s11240-016-1071-9
Martin RC, Liu PP, Goloviznina NA, Nonogaki H (2010) MicroRNA, seeds, and Darwin?: diverse function of miRNA in seed biology and plant responses to stress. J Exp Bot 61:2229–2234
Masciarelli O, Urbani L, Reinoso LH, Luna V (2013) Alternative mechanism for the evaluation of indole-3-acetic acid (IAA) production by Azospirillum brasilense strains and its effects on the germination and growth of maize seedlings. J Microbiol 51:590–597
Miyashima S, Koi S, Hashimoto T, Nakajima K (2011) Non-cell-autonomous microRNA165 acts in a dose-dependent manner to regulate multiple differentiation status in the Arabidopsis root. Development 138:2303–2313
Mockaitis K, Estelle M (2008) Auxin receptors and plant development: a new signaling paradigm. Annu Rev Cell Dev Biol 24:55–80
Ochando I, Jover-Gil S, Ripoll JJ, Candela H, Vera A, Ponce MR, Martinez-Laborda A, Micol JL (2006) Mutations in the microRNA complementarity site of the INCURVATA4 gene perturb meristem function and adaxialize lateral organs in Arabidopsis. Plant Physiol 141:607–619
Oh E, Yamaguchi S, Kamiya Y, Bae GW, Choi G (2006) Light activates the degradation of PIL5 protein to promote seed germination through gibberellin in Arabidopsis. Plant J 47:124–139
Özcan S, Barghchi M, Firek S, Draper J (1993) Efficient adventitious shoot regeneration and somatic embryogenesis in pea. Plant Cell Tissue Organ Culture 34:271–277
Pulido A, Laufs P (2010) Co-ordination of developmental processes by small RNAs during leaf development. J Exp Bot 61:1277–1291
Pullman GS, Bucalo K (2014) Pine somatic embryogenesis: analyses of seed tissue and medium to improve protocol development. New For 45:353–377
Singh A, Singh S, Panigrahi KC, Reski R, Sarkar AK (2014) Balanced activity of microRNA166/165 and its target transcripts from the class III homeodomain-leucine zipper family regulates root growth in Arabidopsis thaliana. Plant Cell Rep 33:945–953
Tsavkelova EA, Cherdyntseva TA, Klimova SY, Shestakov AI, Botinaand SG, Netrusov AI (2007) Orchid-associated bacteria produce indole-3-acetic acid, promote seed germination, and increase their microbial yield in response to exogenous auxin. Arch Microbiol 188:655–664
Vaucheret H, Mallory AC, Bartel DP (2006) AGO1 homeostasis entails coexpression of MIR168 and AGO1 and preferential stabilization of miR168 by AGO1. Mol Cell 22:129–136
Xie Z, Kasschau KD, Carrington JC (2003) Negative feedback regulation of Dicer-Like1 in Arabidopsis by microRNA-guided mRNA degradation.Curr Biol 13:784–789
Yamamoto KT, Mori H, Imaseki H (1992) cDNA cloning of indole-3-acetic acid-regulated genes: Aux22 and SAUR from mung bean (vignaradiata) hypocotyl tissue. Plant Cell Physiol 33:93–97
Zhang S, Zhou J, Han S, Yang W, Li W, Wei H, Li X, Qi L (2010) Four abiotic stress-induced miRNA families differentially regulated in the embryogenic and non-embryogenic callus tissues of Larix leptolepis. Biochem Biophys Res Commun 398:355–360
Zhang J, Zhang S, Han S, Wu T, Li X, Li W, Qi L (2012) Genome-wide identification of microRNAs in larch and stage-specific modulation of 11 conserved microRNAs and their targets during somatic embryogenesis. Planta 236:647–657
Zhang L, Li W, HY Xu, Qi LW, Han SY (2014) Cloning and characterization of four differentially expressed cDNAs encoding NFYA homologs involved in responses to ABA during somatic embryogenesis in Japanese larch (Larix leptolepis). Plant Cell Tissue Organ Culture 117:293–304
Zhong R, Ye ZH (2001) Alteration of auxin polar transport in the Arabidopsis ifl1 mutants. Plant Physiol 126:549–563
Zhou GK, Kubo M, Demura T, Ye ZH (2007) Overexpression of miR165 affects apical meristem formation, organ polarity establishment and vascular development in Arabidopsis. Plant Cell Physiol 48:391–404
Zhou J, Cheng Y, Yin M, Yang E, Gong W, Liu C, Zheng X, Deng K, Ren Z, Zhang Y (2015a) Identification of novel miRNAs and miRNA expression profiling in wheat hybrid necrosis. PLoS ONE doi:10.1371/journal.pone.0117507
Zhou Y, Honda M, Zhu H, Zhang Z, Guo X, Li T, Li Z, Peng X, Nakajima K, Duan L, Zhang X (2015b) Spatiotemporal sequestration of miR165/166 by Arabidopsis Argonaute10 promotes shoot apical meristem maintenance. Cell Rep 10:1819–1827
Zhu H, Hu F, Wang R, Zhou X, Sze SH, Liou LW, Barefoot A, Dickman M, Zhang X (2011) Arabidopsis Argonaute10 specifically sequesters miR166/165 to regulate shoot apical meristem development. Cell 145:242–256
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This work was supported by The National High Technology Research and Development Program of China (2013AA102704) and National Natural Science Foundation of China (31330017).
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Li, ZX., Zhang, LF., Li, WF. et al. MIR166a Affects the Germination of Somatic Embryos in Larixleptolepis by Modulating IAA Biosynthesis and Signaling Genes. J Plant Growth Regul 36, 889–896 (2017). https://doi.org/10.1007/s00344-017-9693-7
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DOI: https://doi.org/10.1007/s00344-017-9693-7