A., Preiss, J. O-4-Linked coniferyl and sinapyl aldehydes in lignifying cell walls are the main targets of the Wiesner (phloroglucinol-HCl) reaction. Images were analyzed using the WinRHIZO software version 5b (Regent Instruments Inc., Quebec, Canada), and by ImageJ software [ImageJ 1.51a, NIH, USA, (Schneider et al., 2012)]. The expression of all tested positive regulators (Figure 9A) was induced by GA3 treatment as evident in ARs sampled at 5W after planting, while expression of IbNAC075 was upregulated earlier, already at 2W (Figure 9A). Expression of class I knotted1-like homeobox genes in the storage roots of sweetpotato (Ipomoea batatas). doi: 310.1046/j.1365-1313X.1998.00217.x, Tanaka, M. (2016). http://www.fao.org/3/b-i6407e.pdf. Morphological characteristics, anatomical structure and gene expression: novel insights into gibberellin biosynthesis and perception during carot growth and development. It has previously been bought for a multiple re-use license which is still valid. For transportation or brief storage, place the leaves between sheets of wet toweling paper and keep in a closed container such as a tin can or a Mason jar. Commu. ( Hoboken, New Jersey: John Wiley & Sons, Inc., Wiley-Blackwell), 157–207. 79, 1–24. Two NAC domain transcription factors, SND1 and NST1, function redundantly in regulation of secondary wall synthesis in fibers of Arabidopsis. Another NAC domain repressor, XYLEM NAC DOMAIN 1 (XND1) was also shown to reduce xylem vessel differentiation and lignin accumulation (Zhao et al., 2008). A., Lomin, S. N., Alekseeva, V. V., et al. Interestingly, GA3 treatment showed a significant reducing effect on starch accumulation also in roots that developed into SRs. 9, 671–675. Métiers : Gestionnaire de données techniques ; Coordinateur de projets en conception ; Responsable R&D ; Responsable de service CFAO ; Développeur de gammes ; Optimisation des process ; Responsable d'îlots ; Qualiticien ; Conseiller consultant en CFAO ou MTAO (métrologie tridimensionnelle assistée par ordinateur). doi: 510.1034/j.1399-3054.2002.1140413.x. (2017). 53, 425–436. Auxin synthesis gene tms1 driven by tuber-specific promoter alters hormonal status of transgenic potato plants and their responses to exogenous phytohormones. The list of all sweetpotato contigs together with the respective Arabidopsis genes is presented in Table 1. Rep. 6, 18645. doi: 18610.11038/srep18645, Wang, S. Y., Sun, T., Faust, M. (1986). Recently, VND and NST genes were suggested as potential regulators of xylem specification in cassava roots (Siebers et al., 2017). In this context, it is of interest to highlight class I knotted 1-like (KNOX) genes, pointed out previously in different plant systems (Arabidopsis, poplar, and sweetpotato) as regulators of plant meristems, including cambial cells (Schrader et al., 2004; Scofield and Murray, 2006; Tanaka et al., 2008). Thus, a relationship between RSA and the developmental fate of sweetpotato ARs was suggested. doi: 1210.1104/pp.1218.00502, Gou, J., Strauss, S. H., Tsai, C. J., Fang, K., Chen, Y., Jiang, X., et al. Genes Dev. 17.2) . Among these, the positive regulators VND5, 6, and 7 are master switches of xylem cell differentiation, regulating protoxylem, and metaxylem differentiation, and secondary wall biosynthesis (Kubo et al., 2005; Yamaguchi et al., 2008; Zhou et al., 2014). Bars (B, C) represent mean of six to eight independent biological replicates (plants) ± SE. Plant Cell. Botany -- Anatomy; Botany -- Morphology; Microscopy -- Technique; Microscopes -- Technique; Botany; Plants -- anatomy & histology; Microscopy. FAOSTAT. Your Lightboxes will appear here when you have created some. Figure 3 Effect of GA3 application on sweetpotato “Georgia Jet” storage-root characteristics. (2017). Effect of exogenous GA3 and its inhibitor paclobutrazol on floral formation, endogenous hormones, and flowering-associated genes in ‘Fuji’ apple (Malus domestica Borkh.). Protoplasma 254, 839–848. (2014). It was further suggested that in ARs with a prevalence of arrested/non-emerged LR primordia, the adjacent stellar tissue becomes lignified, rendering it incapable of undergoing swelling due to the lack of vascular and anomalous cambia development (Villordon and Clark, 2014). Storage-root initiation involves proliferation of vascular cambial cells and starch accumulation (Firon et al., 2013; Ravi et al., 2014). Phloroglucinol-HCl staining (being more specific and indicative of 4-O-linked hydroxycinnamyl aldehyde structures in lignins) stained lignified cells wall, where lignin deposition appears as pink-red color in proto-, meta-, and secondary xylem, and xylem fibers (B). 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. Root system architecture parameters, including root system FW, DW, volume, and surface area, were further recorded at 5W after planting, when SR formation was already detected. The mechanisms underlying this developmental switch are still unclear. Exogenous gibberellin enhances secondary xylem development and lignification in carrot taproot. The expression of yet another GA2-oxidase (IbGA2ox8) was however upregulated by GA3 (1.7-fold in 2W and 5W ARs). Such an interaction between GA and KNOX may affect the balance between lignification, on one hand, and meristem development, on the other hand, and may be highly relevant to the issue of SR formation. Planta 96, 101–108. The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. Highest lignification/lignified area was evident in 2W and 5W samples following GA3 treatment. 96, 4698–4703. Contribution of gibberellins to the formation of Arabidopsis seed coat through starch degradation. Knotted 1-like transcription factors are known regulators involved in the establishment and maintenance of plant meristems, found to be highly expressed in poplar cambial samples (Schrader et al., 2004) and to exhibit upregulated transcript levels in initiating SRs compared to lignified non-SRs (Firon et al., 2013). Sweetpotato is a rich source of carbohydrates, vitamins, dietary fiber, and micronutrients, and is of high importance for food security and for improving the nutrition status in Asia and especially in sub-Saharan Africa. doi: 25510.24161/psb.25504, Hay, A., Kaur, H., Phillips, A., Hedden, P., Hake, S., Tsiantis, M. (2002). (2015). As for root surface area, a significant decrease (more than 3-fold) was recorded for both GA3 and PB treatments at 2W after planting (Figure 2F). The results suggest that regulation of these processes in the root system is achieved at transcript level, and point to the respective genes as a valuable database for further studies, looking into/identifying the regulatory gene network. Significance analysis was performed by using student’s t-test (P ≤ 0.05), where unlike letters represent significant differences between treatments within a sampling group. According to this model, GA has a central and active role in upregulating the upstream master switches of xylem development and lignin biosynthesis, IbNAC075 and IbVND7 transcription factors, which in turn cause upregulation of yet another NAC domain containing regulator, IbSND2. Translocation of paclobutrazol, a gibberellin biosynthesis inhibitor in apple seedlings. (C) Percent (%) root area occupied by xylem vessels (protoxylem, metaxylem and secondary xylem) and xylem fibers. At 5W, the lignified area in GA3-treated roots was represented mainly by fibers, while in PB-treated roots it was represented by proto- and meta-xylem cells. Agric. The effect of different levels of KNOX activity should be further studied in a variety of systems in order to better understand their function. It should be noted that Liebsch et al. doi: 10.1023/B:PRES.0000011916.0000067519.0000011958, PubMed Abstract | CrossRef Full Text | Google Scholar, Belehu, T., Hammes, P. S., Robbertse, P. J. Plant 114, 594–600. BMC Genomics 14, 460. doi: 410.1186/1471-2164-1114-1460, Geigenberger, P. (2011). HortiSci. We made use of the plant hormone GA, shown previously to affect RSA (Gou et al., 2010) and lignification (Wang et al., 2017; Duan et al., 2019), in order to study its effect on sweetpotato root development, SR formation, lignin accumulation, and the expression levels of lignin-biosynthesis, and carbohydrate metabolism/starch-biosynthesis genes as well as potential upstream regulators. During autumn semester 2018, ENAC organized a series of lab visits for interested researchers and students of EPFL. The NAC domain repressor, VND-INTERACTING 2 (VNI2) negatively regulates xylem vessel formation/differentiation and represses VND7-induced expression of vessel-specific genes (Yamaguchi et al., 2010). doi: 410.1111/j.1365-1313X.2005.02547.x, Kaneda, M., Rensing, K. H., Wong, J. C., Banno, B., Mansfield, S. D., Samuels, A. L. (2008). 56, 242–254. doi: 210.1104/pp.1103.036988, Boerjan, W., Ralph, J., Baucher, M. (2003). Similarly, IbGA20ox expression increased significantly by GA3 in ARs harvested at 1W, 2W, and 5W, while IbGA3ox4 expression increased mainly in 5W ARs (Figure 8A). Levels of bioactive (GA1, GA4, and GA7) and inactive (GA20) forms of GA, measured at two weeks (2W) after planting, are presented. We show that application of the plant hormone gibberellin increased stem elongation and root gibberellin levels, while having inhibitory effects on root system parameters, decreasing lateral root number and length, and significantly reducing storage-root number and diameter. Il choisit et optimise les procédés et processus mis en Suvre, analyse, synthétise et corrige. JARQ 50, 293–299. doi: 410.1007/s00299-00016-02091-y, Kubo, M., Udagawa, M., Nishikubo, N., Horiguchi, G., Yamaguchi, M., Ito, J., et al. Plant Cell. Figure 1 Effect of GA3 application on sweetpotato “Georgia Jet” stem growth. Interestingly, gibberellin downregulated root expression levels of orthologues of the Arabidopsis BREVIPEDICELLUS transcription factor (IbKN2 and IbKN3), regulator of meristem maintenance. cultivars. The work was based upon previous findings from our laboratory (in collaboration with the laboratories of A. Villordon and D. LaBonte) demonstrating that (i) the initial ARs that develop from stem-cutting possess the necessary requirements for forming SRs (Villordon et al., 2009); (ii) SR initiation phase spans the first two weeks after planting (Villordon et al., 2009). Hussey, S. G., Mizrachi, E., Spokevicius, A. V., Bossinger, G., Berger, D. K., Myburg, A. In accordance with this hypothesis, GA3 application caused a significant reduction in transcript levels of both IbKN2 and IbKN3 genes. doi: 22910.23390/ijms160922960, Gupta, R., Chakrabarty, S. K. (2013). Behav. Exogenous gibberellin altered morphology, anatomic and transcriptional regulatory networks of hormones in carrot root and shoot. Agric. The results show significant reduction by both GA3 and PB treatments in all tested parameters (Supplementary Figure S4). (2005). Sweetpotato can grow under marginal conditions, thus providing a good solution for nutrition in developing countries (CIP, 2017). Endogenous GAs levels were determined in sweetpotato ARs, derived from 12 plants which were sampled at 2W after planting, according to the established protocol (Kolachevskaya et al., 2017). doi: 10.1101/gad.11.23.3194, Pomar, F., Merino, F., Barcelo, A. R. (2002). Wang, G. L., Xiong, F., Que, F., Xu, Z., Wang, F., Xiong, A. S. (2015a). Lateral root density increased more than 3-fold at 2W as compared to 1W, under all tested conditions, and no significant differences were apparent following GA3 or PB applications (Figure 2E). By performing transcriptional profiling of sweetpotato roots during SR initiation phase, we have previously suggested that down-regulation of lignin biosynthesis and up-regulation of starch biosynthesis are key events at the early stage of SR formation (Firon et al., 2013). Significance analysis was performed by using student’s t-test (P ≤ 0.05), where unlike letters represent significant differences between treatments within a sampling group. The unsatisfactory slides obtained from such material are likely to be interpreted by uncritical observers as the result of poor technicjue. Plant Sci., 15 November 2019 The object is focused through the microscope ocular and the camera is carefully placed upon the ocular. Gibberellin signaling: biosynthesis, catabolism, and response pathways. Gibberellins regulate lateral root formation in Populus through interactions with auxin and other hormones.
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