A link between root system architecture (RSA) parameters and SR initiation and yield potential was suggested (Villordon et al., 2012; Villordon and Clark, 2014; Villordon et al., 2014). Initially, these ARs develop into white lignified roots that support development of the sweetpotato plant. The mechanisms underlying this developmental switch are still unclear. Sectioning was done by a microtome (Leica RM2245, Leica Biosystems, Nussloch, Germany) and 15 µm thick sections were prepared. Over-expression of a tobacco homeobox gene, NTH15, decreases the expression of a gibberellin biosynthetic gene encoding GA 20-oxidase. Plant Cell. Possibilité de suivre ce cursus en contrat de professionnalisation. Lignification is considered part of the plant’s developmental program, being coordinated with the production of cellulose, hemicellulose, and other polysaccharides during secondary wall formation (Bonawitz and Chapple, 2010 and references therein). (2010). 44, 494–504. J. Exp. Similar findings were reported recently in carrot taproot, demonstrating increased lignification following GA3 treatment (Wang et al., 2017). Int. Conditions générales d'utilisation - Mentions légales, Avertissement : cette fiche est en état archivé, Ministère de l'enseignement supérieur et de la recherche, (UNIVERSITE DE PERPIGNAN) Furthermore, it is hypothesized that environmental stress conditions will reduce SR yield by activating similar mechanisms. (2002). Finally, samples containing fresh 6 ml of 80% ethanol were incubated at 70°C for 20 min. doi: 210.1104/pp.1103.036988, Boerjan, W., Ralph, J., Baucher, M. (2003). Biol. You cannot download or purchase for any new licenses. It has previously been bought for a multiple re-use license which is still valid. Sciences et techniques des activités physiques et sportives - STAPS. Hay et al. Alamy charges you a fee for access to the high resolution copy of the image. This image is no longer for sale. doi: 10.1016/j.tplants.2014.02.002. Gibberellin was previously demonstrated to promote xylogenesis, induction of fiber production and fiber length, as well as lignification, in numerous plant systems including tobacco, carrot, and hybrid aspen (Eriksson et al., 2000; Biemelt et al., 2004; Dayan et al., 2010; Wang et al., 2017). doi: 3410.1105/tpc.3110.075036, Olszewski, N., Sun, T., Gubler, F. (2002). These results point to root architecture attributes during the first two weeks of plant development as being important and as playing a role in the developmental transition of the AR into a SR. Figure 12 The effect of GA3 application on expression profiles of sweetpotato “Georgia Jet” carbohydrate metabolism and starch biosynthesis orthologs/genes in adventitious roots (AR) and storage-roots (SR). Expression/transcript levels were measured at 1W, 2W, and 5W after planting for AR and at 5W for SR, using qRT-PCR analyses, and values were normalized relative to the expression levels of phospholipase D1a. Botany -- Anatomy; Botany -- Morphology; Microscopy -- Technique; Microscopes -- Technique; Botany; Plants -- anatomy & histology; Microscopy. For the study of normal structure, select healthy, representative plants. Such genes include phosphoglucomutase (PGM), ADP glucose pyrophosphorylase (AGPase), granule-bound starch synthase (GBSS), and starch phosphorylase (SP) (Geigenberger, 2011). SS provided technical assistance in part of the experiments and starch analyses. The lateral stem length measured at 3W, 4W, and 5W after planting was found to change significantly by GA3 and PB treatments as compared to control (Figure 1). doi: 110.1007/BF00386360. Plant J. (2012). Histochemical staining was done by either, safranin-fast green or Phloroglucinol-HCl (Ph-HCl or Weisner) staining to observe the root vascular system and lignin deposition (phloroglucinol is a good indicator of general cinnamaldehydes), respectively. Figure 13 Schematic presentation showing a central role for gibberellin (GA) in formation of either lignified non-storage roots or storage roots. Some of the vessels are lignified and stained red. The genetics of lignin biosynthesis: connecting genotype to phenotype. Wang, G. L., Xiong, F., Que, F., Xu, Z., Wang, F., Xiong, A. S. (2015a). We have previously suggested that major events involved in SR initiation are the reduction of carbon flow towards phenylpropanoid synthesis and its delivery into carbohydrate metabolism and starch biosynthesis (Firon et al., 2013). Plant microtechnique and microscopy. For safranin-fast green staining, deparaffinized samples were stained for 2 h in safranin-O (1%) with counter staining for 10 s in fast green (0.5%). 15, 290. doi: 10.1186/s12870-015-0679-y, Wang, G. L., Que, F., Xu, Z. S., Wang, F., Xiong, A. S. (2017). VS performed all the experiments. Exogenous GA3 application enhances xylem development and induces the expression of secondary wall biosynthesis related genes in Betula platyphylla. It is worth mentioning that BP orthologues were previously indicated as markers of cambial cells and were shown to regulate development and maintenance of the shoot apical meristem in various plants (Vollbrecht et al., 2000; Schrader et al., 2004). In carrot root, for example, it was demonstrated that transcript levels of genes related to auxin, cytokinin, abscisic acid (ABA), and brassinolides were altered in response to increased or reduced gibberellins (Wang et al., 2015b). For following the effect of GA3 and PB treatments on plant development, lateral stem length (originated from node 10) was measured at 3 weeks (3W), 4W, and 5W after planting, using 16 plants (biological replicates) (Supplementary Figure S1). doi: 10.1073/pnas.96.8.4698. 102, 1040–1049. FAOSTAT. Sitemap. It is prepared by dissolving the common plastic, polystyrene, in a suitable hydrocarbon solvent (usually xylene). By clicking OK, you are confirming that this image is only to be used for the rights in the existing license. – Technicien en optique de précision. No use, distribution or reproduction is permitted which does not comply with these terms. Before loading samples, the column was activated with 100% MeOH, washed with mQ water, and equilibrated with 5% of NH4OH. (2009). The expression pattern of the following GA-related genes was followed during root development at 1W, 2W, and 5W: GA biosynthesis genes, ent-kaurene oxidase (IbKO), GA20-oxidase (IbGA20ox), and GA3-oxidase4 (IbGA3ox4) (Figure 8A); GA catabolizing genes, GA2-oxidase (IbGA2ox1, IbGA2ox3, and IbGA2ox8) (Figure 8B), and genes involved in GA signaling and regulation, GIBBERELLIN INSENSITIVE DWARF1 (IbGID1) and GIBBERELLIC ACID INSENSITIVE (IbGAI) (Figure 8C). Results were analyzed by Rotor gene software, and relative expression levels of targeted genes were calculated by the 2-ΔCt method. doi: 310.1146/annurev-genet-102209-163508, Chaffey, N., Cholewa, E., Regan, S., Sundberg, B. 19, 1855–1860. Total RNA was extracted from sweetpotato ARs at 1W, 2W, and 5W after planting (5W sampled roots included both, ARs and SRs), using RNeasy Plant Mini Kit (Qiagen, Germany). In another model, the camera is held on a bracket attached to the ocular tube, and the camera is swung into position over the ocular (Fig. doi: 1710.1104/pp.1108.121533, Kao, Y., Harding, S. A., Tsai, C. J. BAC PRO MICROTECHNIQUES 1 Simon, Terminale bac pro : Ce que j'aime bien dans la microtechnique, c'est le contrôle, la maîtrise des machines. Botanical microtechnique. This change involves accumulation of starch and is dependent on regulatory mechanisms that are not yet well characterized (Firon et al., 2013; Ravi et al., 2014). The average temperature and relative humidity at this site during the study (13–24 September 2008) were 17.6 ± 4.3 °C and 86.1 ± 16.0 %, as measured hourly in the subcanopy (mean of 2 HOBO Pro … This image could have imperfections as it’s either historical or reportage. Ann. Select from the license options below to get a price. In Arabidopsis, significant metabolic commitment to secondary wall deposition occurs during maturation of xylem vessels, xylary fiber cells, and interfascicular fiber cells in the developing inflorescence stem (Chaffey et al., 2002; Zhong et al., 2006). Autofluorescence imaging of unstained, deparaffinized sections was done by Confocal microscopy (Donaldson and Knox, 2012). Transcript levels of sweetpotato orthologues of the Arabidopsis GA biosynthesis genes IbKO, IbGA20ox, and IbGA3ox and the receptor IbGID1 were highly upregulated by GA3, while transcript levels of genes encoding enzymes of GA deactivation (IbGA2ox1 and IbGA2ox3) were found to be downregulated, matching the induced endogenous GAs levels observed in our study and pointing to the potential existence of a feedforward mechanism. doi: 10.21273/HORTSCI.44.3.651, Villordon, A., LaBonte, D., Solis, J., Firon, N. (2012). Exogenous application of GA3 to sweetpotato plants during the first two weeks of development caused elevated levels of bioactive and non-bioactive GAs in the roots together with an increase in the plant’s stem length. Furthermore, gibberellin enhanced root xylem development, caused increased lignin deposition, and, at the same time, decreased root starch accumulation. Curr. The experimental setup and conditions used are detailed in Supplementary Figure S1. Il choisit et optimise les procédés et processus mis en oeuvre, analyse, synthétise et corrige. Figure 3 Effect of GA3 application on sweetpotato “Georgia Jet” storage-root characteristics. Il élabore un cahier des charges fonctionnel. These results point to IbNAC075 and IbVND7 as potential master switches of root xylem proliferation and lignin biosynthesis, marking them as important candidates for future studies. Figure 8 The effect of GA3 application on expression profiles of sweetpotato “Georgia Jet” orthologs/genes involved in gibberellin biosynthesis (A), catabolism (B), and signaling/regulation (C) in adventitious roots (AR) and storage-roots (SR). Gibberellin affects sweetpotato yield, causing upregulation of root xylem development and lignin biosynthesis, together with downregulation of starch accumulation and inhibition of storage-root formation. Plant Physiol. Significance analysis was performed by using student’s t-test (P ≤ 0.05), where unlike letters represent significant differences between treatments within a group. KNOX gene function in plant stem cell niches. Bars represent mean of four independent biological replicates (plants) ± SE. Il contrôle la conformité et la qualité des produits en cours de production et finis. AGPase, ADP glucose pyrophosphorylase; AR, adventitious root; BP, BREVIPEDICELLUS; CAD, cinnamyl alcohol dehydrogenase; CCoAOMT, caffeoyl-CoA O-methyltransferase; C4H, cinnamate 4-hydroxylase; 4CL, 4-coumarate:CoA ligase; GA, gibberellin; GAI, gibberellic acid insensitive; GBSS, granule-bound starch synthase; GID1, GA insensitive dwarf 1; GA2ox, GA 2-oxidase; GA20ox, GA 20-oxidase; GA3ox, GA 3-oxidase; HCT, p-Hydroxycinnamoyl-CoA: quinate shikimate p-hydroxycinnamoyltransferase; KNOX, Class I knotted 1-like; KO, ent-kaurene oxidase; LR, lateral root; NST/SND, NAC secondary-wall thickening promoting factor/secondary-wall-associated NAC domain protein; PAL, phenylalanine ammonia-lyase; PB, paclobutrazol; PGM, phosphoglucomutase; Ph-HCl, phloroglucinol-HCl; RSA, root system architecture; SP, starch phosphorylase; SR, storage-root; SuSy, sucrose synthase; VND, vascular-related NAC domain; VNI2, VND-INTERACTING2; XND1, XYLEM NAC DOMAIN 1. Enter your log in email address and we'll send you a link to reset your password. Genet. Cross-sections of ARs at 1W and 2W after planting show that root anatomy was influenced by both GA3 and PB treatments, exhibiting higher number of xylem vessels (Figure 5A). If the material is to be kill. Combined supernatants were dried in a Speed-Vac concentrator (Savant SC210A, Thermo, US), reconstituted by 5% of NH4OH (v/v) and loaded on Oasis® MAX column (6 cc/150 mg, Waters Co., Milford, MA, USA).
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