De novo transcriptome sequencing in Ficus hirta Vahl. (Moraceae) to investigate gene regulation involved in the biosynthesis of pollinator attracting volatiles
- 492 Downloads
Flower volatile organic compounds (VOCs) emitted from the receptive figs of Ficus (Moraceae) play important roles in maintaining the specificity of pollinator attraction and reproductive isolation between host species. The dominant components of VOCs are terpenoids, and while the genes involved in terpenoid biosynthesis are known, we know very little about the regulation of these genes and its relationship to pollinator attraction in Ficus. Thus, we selected pre-receptive (pre-VOC attractant-emitting) and receptive (VOC attractant-emitting) phase female flowers of a dioecious fig for transcriptome sequencing to investigate the differential activity of genes, including those related to terpenoid biosynthesis. We annoted 53,445 unigenes, of which 608 were found to be differently expressed in the two stages, with 242 unigenes upregulated and 366 unigenes downregulated in pre-receptive relative to receptive phase flowers. With respect to the production of VOCs, 80 unigenes encoded 34 enzyme-coding genes involved in terpenoid biosynthesis, including nearly all key enzymes of the MVA and MEP pathways forming the backbone of terpenoid biosynthesis. We designed pair primers for 16 of these 34 enzyme genes and validated 5 of them in 30 Ficus species representing 6 subgenera. In addition to the transcript sequences, we identified 35,558 putative microsatellite loci and designed primers for 11,468 of them. Our data and results will contribute to genetic research on terpene biosynthesis in figs and will aid in the understanding of the morphological and chemical changes that occur as the female flowers develop and produce pollinator-specific VOCs.
KeywordsFig Fig wasp RNA-Seq VOC Terpenoid biosynthesis Microsatellite
The authors thank Prof. Zhang Mingyong, Dr. Xia Kuaifei, and Dr. Zeng Jiqing from South China Botanical Garden, the Chinese Academy of Sciences for their support with the transcriptome sequencing. We also thank three anonymous reviewers for extensive comments on this manuscript. This study was supported by the National Basic Research Program of China (973 Program) (2014CB954103), National Natural Science Foundation of China (31370409), Natural Science Foundation of Guangdong Province (S2013020012814), and the Applied Fundmental Research Foundation of Yunnan Province (2014GA003).
Conflict of interest
The authors declared that they have no competing interests.
Data archiving statement
Raw sequence reads are available from NCBI SRA (SRX951263 and SRX951272).
- Carretero-Paulet L, Cairo A, Botella-Pavia P, Besumbes O, Campos N, Boronat A, Rodriguez-Concepcion M (2006) Enhanced flux through the methylerythritol 4-phosphate pathway in Arabidopsis plants overexpressing deoxyxylulose 5-phosphate reductoisomerase. Plant Mol Biol 62:683–695. doi: 10.1007/s11103-006-9051-9 CrossRefPubMedGoogle Scholar
- Enfissi EM, Fraser PD, Lois LM, Boronat A, Schuch W, Bramley PM (2005) Metabolic engineering of the mevalonate and non-mevalonate isopentenyl diphosphate-forming pathways for the production of health-promoting isoprenoids in tomato. Plant Biotechnol J 3:17–27. doi: 10.1111/j.1467-7652.2004.00091.x CrossRefPubMedGoogle Scholar
- Guevara-Garcia A, San Roman C, Arroyo A et al (2005) Characterization of the Arabidopsis clb6 mutant illustrates the importance of posttranscriptional regulation of the methyl-d-erythritol 4-phosphate pathway. Plant Cell 17:628–643. doi: 10.1105/tpc.104.028860 PubMedCentralCrossRefPubMedGoogle Scholar
- Ikegami H, Habu T, Mori K, Nogata H, Hirata C, Hirashima K, Tashiro K, Kuhara S (2013) De novo sequencing and comparative analysis of expressed sequence tags from gynodioecious fig (Ficus carica L.) fruits: caprifig and common fig. Tree Genet Genomes 9:1075–1088. doi: 10.1007/s11295-013-0622-z CrossRefGoogle Scholar
- Morris WL, Ducreux LJM, Hedden P, Millam S, Taylor MA (2006) Overexpression of a bacterial 1-deoxy-d-xylulose 5-phosphate synthase gene in potato tubers perturbs the isoprenoid metabolic network: implications for the control of the tuber life cycle. J Exp Bot 57:3007–3018. doi: 10.1093/jxb/erl061 CrossRefPubMedGoogle Scholar
- Proffit M, Johnson SD (2009) Specificity of the signal emitted by figs to attract their pollinating wasps: comparison of volatile organic compounds emitted by receptive syconia of Ficus sur and F. sycomorus in Southern Africa. S Afr J Bot 75:771–777. doi: 10.1016/j.sajb.2009.08.006 CrossRefGoogle Scholar
- Van Noort S, Ware AB, Compton SG (1989) Pollinator-specific volatile attractants released from figs of Ficus burtt-davyi. S Afr J Sci 85:323–324Google Scholar
- Vignes H, Hossaert-McKey M, Beaune D, Fevre D, Anstett MC, Borges RM, Kjellberg F, Chevallier MH (2006) Development and characterization of microsatellite markers for a monoecious Ficus species, Ficus insipida, and crossspecies amplification among different sections of Ficus. Mol Ecol Notes 6:792–795. doi: 10.1111/j.1471-8286.2006.01347.x CrossRefGoogle Scholar