scholarly journals Characterization of Adventitious Root Development in Sweetpotato

HortScience ◽  
2009 ◽  
Vol 44 (3) ◽  
pp. 651-655 ◽  
Author(s):  
Arthur Q. Villordon ◽  
Don R. La Bonte ◽  
Nurit Firon ◽  
Yanir Kfir ◽  
Etan Pressman ◽  
...  

Adventitious roots of ‘Beauregard’ and ‘Georgia Jet’ sweetpotato were observed and anatomically characterized over a period of 60 days of storage root development. The majority of ‘Beauregard’ and ‘Georgia Jet’ adventitious roots sampled at 5 to 7 days after transplanting (DAT) possessed anatomical features (five or more protoxylem elements) associated with storage root development. The majority of ‘Beauregard’ (86%) and ‘Georgia Jet’ (89%) storage roots sampled at 60 to 65 DAT were traced directly to adventitious roots extant at 5 to 7 DAT. The two varieties, however, differed in the timing in which regular and anomalous cambia were formed. Regular vascular cambium development, i.e., initiation and completion, was observed in both varieties at 19 to 21 DAT. Formation of complete regular vascular cambium was negligible for ‘Beauregard’ (4%) in comparison with ‘Georgia Jet’ (32%) at 26 to 28 DAT. However, anomalous cambia development adjacent to xylem elements was greater in ‘Beauregard’ (30%) in comparison with ‘Georgia Jet’ (13%). Nearly 40% to 50% of samples in both varieties showed extensive lignification in the stele region. At 32 to 35 DAT, 62% to 70% of the adventitious roots for both varieties had either been initiated (developed anomalous cambium) or were lignified. The remaining adventitious roots showed intermediate stages of vascular cambium development. The adventitious root count increased up to 19 to 21 DAT and then remained constant up to 32 to 35 DAT. These accumulated results suggest that the initial stages of adventitious root development are critical in determining storage root set in sweetpotato.

2011 ◽  
Author(s):  
Don LaBonte ◽  
Etan Pressman ◽  
Nurit Firon ◽  
Arthur Villordon

Original objectives: Anatomical study of storage root initiation and formation. Induction of storage root formation. Isolation and characterization of genes involved in storage root formation. During the normal course of storage root development. Following stress-induced storage root formation.   Background:Sweetpotato is a high value vegetable crop in Israel and the U.S. and acreage is expanding in both countries and the research herein represents an important backstop to improving quality, consistency, and yield. This research has two broad objectives, both relating to sweetpotato storage root formation. The first objective is to understand storage root inductive conditions and describe the anatomical and physiological stages of storage root development. Sweetpotato is propagated through vine cuttings. These vine cuttings form adventitious roots, from pre-formed primordiae, at each node underground and it is these small adventitious roots which serve as initials for storage and fibrous (non-storage) “feeder” roots. What perplexes producers is the tremendous variability in storage roots produced from plant to plant. The marketable root number may vary from none to five per plant. What has intrigued us is the dearth of research on sweetpotato during the early growth period which we hypothesize has a tremendous impact on ultimate consistency and yield. The second objective is to identify genes that change the root physiology towards either a fleshy storage root or a fibrous “feeder” root. Understanding which genes affect the ultimate outcome is central to our research. Major conclusions: For objective one, we have determined that the majority of adventitious roots that are initiated within 5-7 days after transplanting possess the anatomical features associated with storage root initiation and account for 86 % of storage root count at 65 days after transplanting. These data underscore the importance of optimizing the growing environment during the critical storage root initiation period. Water deprivation during this phenological stage led to substantial reduction in storage root number and yield as determined through growth chamber, greenhouse, and field experiments. Morphological characterization of adventitious roots showed adjustments in root system architecture, expressed as lateral root count and density, in response to water deprivation. For objective two, we generated a transcriptome of storage and lignified (non-storage) adventitious roots. This transcriptome database consists of 55,296 contigs and contains data as regards to differential expression between initiating and lignified adventitious roots. The molecular data provide evidence that a key regulatory mechanism in storage root initiation involves the switch between lignin biosynthesis and cell division and starch accumulation. We extended this research to identify genes upregulated in adventitious roots under drought stress. A subset of these genes was expressed in salt stressed plants.


Plant Methods ◽  
2019 ◽  
Vol 15 (1) ◽  
Author(s):  
Michael Gomez Selvaraj ◽  
Maria Elker Montoya-P ◽  
John Atanbori ◽  
Andrew P. French ◽  
Tony Pridmore

Abstract Background Root and tuber crops are becoming more important for their high source of carbohydrates, next to cereals. Despite their commercial impact, there are significant knowledge gaps about the environmental and inherent regulation of storage root (SR) differentiation, due in part to the innate problems of studying storage roots and the lack of a suitable model system for monitoring storage root growth. The research presented here aimed to develop a reliable, low-cost effective system that enables the study of the factors influencing cassava storage root initiation and development. Results We explored simple, low-cost systems for the study of storage root biology. An aeroponics system described here is ideal for real-time monitoring of storage root development (SRD), and this was further validated using hormone studies. Our aeroponics-based auxin studies revealed that storage root initiation and development are adaptive responses, which are significantly enhanced by the exogenous auxin supply. Field and histological experiments were also conducted to confirm the auxin effect found in the aeroponics system. We also developed a simple digital imaging platform to quantify storage root growth and development traits. Correlation analysis confirmed that image-based estimation can be a surrogate for manual root phenotyping for several key traits. Conclusions The aeroponic system developed from this study is an effective tool for examining the root architecture of cassava during early SRD. The aeroponic system also provided novel insights into storage root formation by activating the auxin-dependent proliferation of secondary xylem parenchyma cells to induce the initial root thickening and bulking. The developed system can be of direct benefit to molecular biologists, breeders, and physiologists, allowing them to screen germplasm for root traits that correlate with improved economic traits.


2021 ◽  
Author(s):  
Camilo Humberto Parada Rojas ◽  
Kenneth Pecota ◽  
Christie Almeyda ◽  
G. Craig Yencho ◽  
Lina Quesada-Ocampo

Black rot of sweetpotato caused by Ceratocystis fimbriata, is an important reemerging disease threatening sweetpotato production in the United States. This study assessed disease susceptibility of the storage root surface, storage root cambium, and slips (vine cuttings) of 48 sweetpotato cultivars, advanced breeding lines, and wild relative accessions. We also characterized the effect of storage root development on susceptibility to C. fimbriata. None of the cultivars examined at the storage root level were resistant, with most cultivars exhibiting similar levels of susceptibility. In storage roots, Jewel and Covington were the least susceptible and significantly different from White Bonita, the most susceptible cultivar. In the slip, significant differences in disease incidence were observed for above and below ground plant structures among cultivars, advanced breeding lines, and wild relative accessions. Burgundy and Ipomoea littoralis displayed less below ground disease incidence as compared to NASPOT 8, Sunnyside and LSU-417, the most susceptible cultivars. Correlation of black rot susceptibility between storage roots and slips was not significant, suggesting that slip assays are not useful to predict resistance in storage roots. Immature, early developing storage roots were comparatively more susceptible than older, fully developed storage roots. The high significant correlation between storage root cross-section area and cross-sectional lesion ratio suggests the presence of an unfavorable environment for C. fimbriata as the storage root develops. Incorporating applications of effective fungicides at transplanting and during early storage root development when sweetpotato tissues are most susceptible to black rot infection may improve disease management efforts.


HortScience ◽  
2020 ◽  
Vol 55 (9) ◽  
pp. 1463-1467 ◽  
Author(s):  
Benjamin E. Deloso ◽  
Anders J. Lindström ◽  
Frank A. Camacho ◽  
Thomas E. Marler

The influences of indole-3-butyric acid (IBA) concentrations of 0–30 mg·g−1 on the success and speed of adventitious root development of Zamia furfuracea L.f. and Zamia integrifolia L.f. stem cuttings were determined. Root formation success for both species was greater than 95%. The IBA concentrations did not influence the speed of root development for Z. furfuracea, but the Z. integrifolia cuttings that received IBA concentration of 3 mg·g−1 generated adventitious roots more slowly than the cuttings in the control group. The ending dry weights of the stems, leaves, and roots were not influenced by IBA concentration for either species. Our results indicated that adventitious root formation on stem cuttings of these two Zamia species is successful without horticultural application of IBA. Additional IBA studies are needed on the other 300+ cycad species, especially those that are in a threatened category.


2021 ◽  
Author(s):  
Fuyun Hou ◽  
Zhen Qin ◽  
Taifeng Du ◽  
Yuanyuan Zhou ◽  
Aixian Li ◽  
...  

Abstract BackgroundSweetpotato(Ipomoea batatas (L.) Lam.) is one of the most important crops with high storage roots yield. Lignin affects the storage root formation. However, the molecular mechanisms of lignin biosynthesis in storage roots development have been lacking.ResultsTo reveal the molecular mechanism of lignin biosynthesis and identify new homologous genes in lignin biosynthesis during storage root development, the storage root (SR) at three different stages (D1, D2 and D3) in the two cultivars (Jishu25 and Jishu29) was investigated with full-length and second-generation transcriptome. A total of 52,137 transcripts and 21,148 unigenes were obtained after corrected with Hiseq2500 sequencing. Through the comparative analysis, 9577 unigenes were found to be differently expressed in the different stage in two cultivars. Among of them, 91 unigenes enriched in the phenylpropanoid biosynthesis, and 201 unigenes in hormone signal transduction pathway with KEGG analysis. Weighted gene co-expression network analysis of differentially expressed unigenes showed that lignin biosynthesis genes might be co-expressed with transcription factors such as AP2/ERF and MYB at the transcription level, and regulated by phytohormones auxin and GA3.ConclusionsTaken together, our findings will throw light on molecular regulatory mechanism of lignin biosynthesis involved in storage root development.


HortScience ◽  
2011 ◽  
Vol 46 (3) ◽  
pp. 513-517 ◽  
Author(s):  
Arthur Villordon ◽  
Don LaBonte ◽  
Julio Solis

A scanner-based minirhizotron (MR) system detected initial adventitious root (AR) development associated with transplant establishment. The system also documented the transition of ARs into pencil roots (PRs) and, in some cases, storage roots (SRs). In general, the MR system underestimated destructive sampling-based (DS) estimates of newly initiated AR (NAR), PR, and SR counts. Angled or vertical single sampling tubes underestimated NAR count by 85% and 79%, respectively. Regardless of installation position, single tube-based measurements underestimated PR and SR count by 83% and 95%, respectively. However, it was found that two vertically installed tubes underestimated NAR count by only 48%. The potential ability of paired sampling tubes to discriminate NAR count differences in response to experimental treatments was confirmed in a simple rain shelter experiment. The paired MR and DS systems detected 83% and 56% reduction in NAR count among plots with rain shelters, respectively. However, it appeared that the presence of tubes interfered with SR formation of monitored AR segments. Despite this limitation, the results show the potential for incorporating MR systems in ongoing and future studies that aim to qualitatively and quantitatively document sweetpotato AR system response to agroclimatic variables and management interventions during the initial SR bulking stage.


2021 ◽  
Author(s):  
Haoyun Sun ◽  
Jingzhao Mei ◽  
Wenqian Hou ◽  
Yang Zhang ◽  
Tao Xu ◽  
...  

Abstract Background As a major family of plant-specific transcription factors, SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) genes play crucial regulatory roles in plant growth, development, and stress tolerance. SPL transcription factor family has been widely studied in various plant species, however, there are no systematic studies on SPL genes in genus Ipomoea. Results In this study, a total of 29, 27, 26, 23 SPL genes were identified in Ipomoea batatas, Ipomoea trifida, Ipomoea triloba, and Ipomoea nil, respectively. Phylogenetic analysis indicated that Ipomoea SPL genes could be clustered into eight clades. SPL members within the same clade showed similar gene structures, domain organizations, and cis-acting element compositions, suggesting similarity of biological function potentially. Evolutionary analysis revealed that segmental duplication events played a major role in the Ipomoea genus-specific expansion of SPL genes. Of these Ipomoea SPL genes, 69 were predicted as the target genes of miR156, and 7 IbSPL genes were further confirmed by degradome data. Additionally, IbSPL genes showed diverse expression patterns in various tissues, implying their functional conservation and divergence. Finally, by combining the information from expression patterns and regulatory sub-networks, we found that four IbSPL genes (IbSPL16/IbSPL17/IbSPL21/IbSPL28) may be involved in the formation and development of storage roots. Conclusions This study not only provides novel insights into the evolutionary and functional divergence of the SPL genes in all available sequenced species in genus Ipomoea, but also lays a foundation for further elucidation of the potential functional roles of IbSPL genes during storage root development.


Sign in / Sign up

Export Citation Format

Share Document