Histological, hormonal and transcriptomic reveal the changes upon gibberellin-induced parthenocarpy in pear fruit

Abstract

Phytohormones play crucial roles in fruit set regulation and development. Here, gibberellins (GA₄₊₇), but not GA₃, induced pear parthenocarpy. To systematically investigate the changes upon GA₄₊₇ induced pear parthenocarpy, dynamic changes in histology, hormone and transcript levels were observed and identified in unpollinated, pollinated and GA₄₊₇-treated ovaries. Mesocarp cells continued developing in both GA₄₊₇-treated and pollinated ovaries. In unpollinated ovaries, mesocarp cells stopped developing 14 days after anthesis. During fruit set process, GA₄₊₇, but not GA₁₊₃, increased after pollination. Abscisic acid (ABA) accumulation was significantly repressed by GA₄₊₇ or pollination, but under unpollinated conditions, ABA was produced in large quantities. Moreover, indole-3-acetic acid biosynthesis was not induced by GA₄₊₇ or pollination treatments. Details of this GA–auxin–ABA cross-linked gene network were determined by a comparative transcriptome analysis. The indole-3-acetic acid transport-related genes, mainly auxin efflux carrier component genes, were induced in both GA₄₊₇-treated and pollinated ovaries. ABA biosynthetic genes of the 9-cis-epoxycarotenoid dioxygenase family were repressed by GA₄₊₇ and pollination. Moreover, directly related genes in the downstream parthenocarpy network involved in cell division and expansion (upregulated), and MADS-box family genes (downregulated), were also identified. Thus, a model of GA-induced hormonal balance and its effects on parthenocarpy were established.

References

[1] Ruan, Y. L., Patrick, J. W., Bouzayen, M., Osorio, S. & Fernie, A. R. Molecular regulation of seed and fruit set. Trends Plant Sci. 17, 656-665 (2012).

[2] Ramírez, F. & Davenport, T. L. Apple pollination: a review. Sci. Hortic. 162, 188-203 (2013).

[3] Gillaspy, G., Ben-David, H. & Gruissem, W. Fruits: a developmental perspective. Plant Cell 5, 1439-1451 (1993).

[4] Ding, J. G. et al. Cytokinin-induced parthenocarpic fruit development in tomato is partly dependent on enhanced gibberellin and auxin biosynthesis. PLoS ONE 8, e70080 (2013).

[5] Mesejo, C., Reig, C., Martínez-Fuentes, A. & Agustí, M. Parthenocarpic fruit production in loquat Eriobotrya japonica Lindl by using gibberellic acid. Sci. Hortic. 126, 37-41 (2010).

[6] Niu, Q. F. et al. Effects of exogenous application of GA₄₊₇ and N-2-chloro-4-pyridyl-N′-phenylurea on induced parthenocarpy and fruit quality in Pyrus pyrifolia ‘Cuiguan’ . Plant Growth Regul. 76, 251-258 (2015).

[7] Sugiyama, K., Kami, D. & Muro, T. Induction of parthenocarpic fruit set in watermelon by pollination with bottle gourd Lagenaria siceraria Molina Standl pollen. Sci. Hortic. 171, 1-5 (2014).

[8] Mesejo, C., Yuste, R., Reig, C. & Martínez-Fuente, A. Gibberellin reactivates and maintains ovary-wall cell division causing fruit set in parthenocarpic Citrus species. Plant Sci. 247, 13-24 (2016).

[9] Nitsch, J. P. Plant hormones in the development of fruits. Q. Rev. Biol. 27, 33-57 (1952).

[10] de Jong, M., Wolters-Arts, M., Feron, R., Mariani, C. & Vriezen, W. H. The Solanum lycopersicum auxin response factor 7 SlARF7 regulates auxin signaling during tomato fruit set and development. Plant J. 57, 160-170 (2009).

[11] Du, L. et al. SmARF8, a transcription factor involved in parthenocarpy in eggplant. Mol. Genet. Genom. 291, 93-105 (2016).

[12] Wang, H. et al. The tomato Aux/IAA transcription factor IAA9 is involved in fruit development and leaf morphogenesis. Plant Cell 17, 2676-2692 (2005).

[13] Serrani, J. C., Carrera, E., Ruiz-Rivero, O. & Gallego-Giraldo, L. Inhibition of auxin transport from the ovary or from the apical shoot induces parthenocarpic fruit-set in tomato mediated by gibberellins. Plant Physiol. 153, 851-862 (2010).

[14] Fos, M., Proaño, K., Nuezc, F. & García-Martínez, J. L. Role of gibberellins in parthenocarpic fruit development induced by the genetic system pat-3/pat-4 in tomato. Plant Physiol. 111, 545-550 (2001).

[15] Greco, M., Chiappetta, A., Bruno, L . & Bitonti, M. B. Posidonia oceanica cadmium induces changes in DNA methylation and chromatin patterning. J. Exp. Bot. 63, 695-709 (2012).

[16] Martinez-Bello, L., Moritz, T. & Lopez-Diaz, I. Silencing C19-GA 2-oxidases induces parthenocarpic development and inhibits lateral branching in tomato plants. J. Exp. Bot. 66, 5897-5910 (2015).

[17] Marti, C. et al. Silencing of DELLA induces facultative parthenocarpy in tomato fruits. Plant J. 52, 865-876 (2007).

[18] Harberd, N. P., Belfield, E. & Yasumura, Y. The angiosperm gibberellin-GID1-DELLA growth regulatory mechanism: how an “Inhibitor of an Inhibitor” enables flexible response to fluctuating environments. Plant Cell 21, 1328-1339 (2009).

[19] Hirano, K. et al. Characterization of the molecular mechanism underlying gibberellin perception complex formation in rice. Plant Cell 22, 2680-2696 (2010).

[20] Ampomah-Dwamena, C. Down-Regulation of TM29, a Tomato SEPALLATA homolog, causes parthenocarpic fruit development and floral reversion. Plant Physiol. 130, 605-617 (2002).

[21] Yao, J. L., Dong, Y. H. & Morris, B. A. M. Parthenocarpic apple fruit production conferred by transposon insertion mutations in a MADS-box transcription factor. Proc. Natl Acad. Sci. USA 98, 1306-1311 (2001).

[22] Klap, C. et al. Tomato facultative parthenocarpy results from SlAGAMOUS-LIKE 6 loss of function. Plant Biotechnol. J. 155, 634 (2017).

[23] Yang, J. C., Zhang, J. H., Wang, J. Q., Zhu, Q. S. & Liu, L. J. Water deficit-induced senescence and its relationship to the remobilization of pre-stored carbon in wheat during grain filling. Agro J. 93, 196-206 (2001).

[24] Henwood, A. Formalin pigment from formaldehyde-acetic acid-alcohol fixed tissues?. J. Histotechnol. 33, 109-111 (2010).

[25] in, Z. Q. et al. AtCDC5 regulates the G2 to M transition of the cell cycle and is critical for the function of Arabidopsis shoot apical meristem. Cell Res. 17, 815-828 (2007).

[26] Matilla, M. A. & Salmond, G. P. C. Complete genome sequence of serratia plymuthica bacteriophage Ф MAM1. J. Virol. 86, 13872-13873 (2012).

[27] Haas, B. J. et al. De novo transcript sequence reconstruction from RNA-Seq: reference generation and analysis with Trinity. Nat. Protoc. 8, 1494-1512 (2013).

[28] Li, R. et al. SOAP2: an improved ultrafast tool for short read alignment. Bioinformatics 25, 1966-1967 (2009).

[29] Langmead, B., Trapnell, C., Pop, M. & Salzberg, S. L. Ultrafast and memory-efficient alignment of short DNA sequences to the human genome. Genome Biol. 10, R25 (2009).

[30] Wapinski, O. L. et al. Hierarchical mechanisms for direct reprogramming of fibroblasts to neurons. Cell 155, 621-635 (2013).

[31] Lohse, M. et al. Mercator: a fast and simple web server for genome scale functional annotation of plant sequence data. Plant Cell Environ. 37, 1250-1258 (2014).

[32] Thimm, O. et al. Mapman: a user-driven tool to display genomics data sets onto diagrams of metabolic pathways and other biological processes. Plant J. 37, 914-939 (2004).

[33] Masiero, S., Colombo, L., Grini, P. E., Schnittger, A. & Kater, M. M. The emerging importance of type I MADS box transcription factors for plant reproduction. Plant Cell 23, 865-872 (2011).

[34] Serrani, J. C., Fos, M., Atarés, A. & García-Martínez, J. L. Effect of gibberellin and auxin on parthenocarpic fruit growth induction in the cv micro-tom of tomato. J. Plant Growth Regul. 26, 211-221 (2007).

[35] Jung, C. J. et al. Gibberellin application at pre-bloom in grapevines down-regulates the expressions of VvIAA9 and VvARF7, negative regulators of fruit set initiation, during parthenocarpic fruit development. PLoS ONE 9, e95634 (2014).

[36] Liu, X. et al. The role of gibberellins and auxin on the tomato cell layers in pericarp via the expression of ARFs regulated by miRNAs in fruit set. Acta Physiol. Plant 38, 77 (2016).

[37] Wang, H. et al. ICK1, a cyclin-dependent protein kinase inhibitor from Arabidopsis thaliana interacts with both Cdc2a and CycD3, and its expression is induced by abscisic acid and its expression is induced by abscisic acid. Plant J. 15, 501-510 (1998).

[38] Nitsch, L. M. et al. Abscisic acid levels in tomato ovaries are regulated by LeNCED1 and SlCYP707A. Planta 229, 1335-1346 (2009).

[39] Vivian-Smith, A. & Koltunow, A. M. Genetic analysis of growth regulator-induced parthenocarpy in Arabidopsis. Plant Physiol. 121, 437-451 (1999).

[40] Beemster, G. T. S. et al. Genome-wide analysis of gene expression profiles associated with cell cycle transitions in growing organs of Arabidopsis. Plant. Physiol. 138, 734-743 (2005).

[41] InzéD, V. L. D. Cell cycle regulation in plant development. Annu. Rev. Genet. 40, 77-105 (2006).

[42] Breyne, P. et al. Transcriptome analysis during cell division in plants. PNAS 99, 14825-14830 (2002).

[43] Malladi, A. & Johnson, L. K. Expression profiling of cell cycle genes reveals key facilitators of cell production during carpel development, fruit set, and fruit growth in apple Malusxdomestica Borkh.. J. Exp. Bot. 62, 205-219 (2011).

[44] Bashline, L., Lei, L., Li, S. & Gu, Y . Cell wall, cytoskeleton, and cell expansion in higher plants. Mol. Plant 7, 586-600 (2014).

[45] Kende, H., Bradford, K., Brummell, D., Cho, H. & Cosgrove, D. Nomenclature for members of the expansin superfamily of genes and proteins. Plant Mol. Biol. 55, 311-314 (2004).

[46] Cosgrove, D. J. Relaxation in a high-stress envirsnment: the molecular bases of extensible cell walls and cell enlargement. Plant Cell 9, 1031-1041 (1997).

[47] Atkinson, R. G., Johnston, S. L., Yauk, Y., Sharma, N. N. & Schröder, R. Analysis of xyloglucan endotransglucosylase/hydrolase XTH gene families in kiwifruit and apple. Postharvest Biol. Tec. 51, 149-157 (2009).

[48] Klinghammer, M. & Tenhaken, R. Genome-wide analysis of the UDP-glucose dehydrogenase gene family in Arabidopsis, a key enzyme for matrix polysaccharides in cell walls. J. Exp. Bot. 58, 3609-3621 (2007).

[49] Wang, H. et al. Regulatory features underlying pollination-dependent and -independent tomato fruit set revealed by transcript and primary metabolite profiling. Plant Cell 21, 1428-1452 (2009).

[50] Ruiu, F., Picarella, M. E., Imanishi, S. & Mazzucato, A. A transcriptomic approach to identify regulatory genes involved in fruit set of wild-type and parthenocarpic tomato genotypes. Plant Mol. Biol. 89, 263-278 (2015).

[51] Mazzucato, A., Olimpieri, I., Siligato, F., Picarella, M. E. & Soressi, G. P. Characterization of genes controlling stamen identity and development in a parthenocarpic tomato mutant indicates a role for the DEFICIENS ortholog in the control of fruit set. Physiol. Plant 132, 526-537 (2008).

[52] Theißen, G. Development of floral organ identity: stories from the MADS house. Curr. Opin. Biol. 4, 75-85 (2001).

[53] Li, X. M. et al. Functional conservation and divergence of four ginger AP1/AGL9 MADS-box genes revealed by analysis of their expression and protein-protein interaction, and ectopic expression of AhFUL gene in Arabidopsis. PLoS ONE 9, e114134 (2014).