Auxin signaling and vascular cambium formation enable storage metabolism in cassava tuberous roots.
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ABSTRACT:
SUBMITTER: Ruscher D
PROVIDER: S-EPMC8096603 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Vascular cambium, a lateral plant meristem, is a central producer of woody biomass. Although a few transcription factors have been shown to regulate cambial activity1, the phenotypes of the corresponding loss-of-function mutants are relatively modest, highlighting our limited understanding of the underlying transcriptional regulation. Here, we use cambium cell-specific transcript profiling followed by a combination of transcription factor network and genetic analyses to identify 62 new transcription factor genotypes displaying an array of cambial phenotypes. This approach culminated in virtual loss of cambial activity when both WUSCHEL-RELATED HOMEOBOX 4 (WOX4) and KNOTTED-like from Arabidopsis thaliana 1 (KNAT1; also known as BREVIPEDICELLUS) were mutated, thereby unlocking the genetic redundancy in the regulation of cambium development. We also identified transcription factors with dual functions in cambial cell proliferation and xylem differentiation, including WOX4, SHORT VEGETATIVE PHASE (SVP) and PETAL LOSS (PTL). Using the transcription factor network information, we combined overexpression of the cambial activator WOX4 and removal of the putative inhibitor PTL to engineer Arabidopsis for enhanced radial growth. This line also showed ectopic cambial activity, thus further highlighting the central roles of WOX4 and PTL in cambium development.
| S-EPMC6795544 | biostudies-literature
Project description:Mechanisms related to the development of cassava storage roots and starch accumulation remain largely unknown. To evaluate genome-wide expression patterns during cassava tuberization, a 60-mer oligonucleotide microarray representing 20,840 cassava genes was designed to identify differentially expressed transcripts in fibrous root, developing storage root and mature storage root. Using a random variance model and the traditional two-fold change method for statistical analysis, 912 and 3386 differentially expressed genes were identified related to the three different phases. Among 25 significant pathways identified, glycolysis/gluconeogenesis was the most important pathway signature due to its effects on other pathways. Rate-limiting enzymes were identified from each individual pathway, such as pectinesterase, enolase, L-lactate dehydrogenase and aldehyde dehydrogenase in glycolysis/gluconeogenesis, and ADP-glucose pyrophosphorylase, starch branching enzyme and glucan phosphorylase in sucrose and starch metabolism. This study revealed that dynamic changes in at least 16% of the transcriptome, including hundreds of transcription factors, oxidoreductases/transferases/hydrolases, hormone-related genes, and effectors of homeostasis, all of which highlight the complexity of this biological process. The reliability of differentially expressed genes in microarray analysis was further verified by quantitative real-time RT-PCR. The genome-wide transcription analysis facilitates our understanding of the formation of the storage root and deciphers key genes for further cassava improvement.
2011-05-13 | GSE25813 | GEO
Project description:BackgroundProteomics is increasingly becoming an important tool for the study of many different aspects of plant functions, such as investigating the molecular processes underlying in plant physiology, development, differentiation and their interaction with the environments. To investigate the cassava (Manihot esculenta Crantz) proteome, we extracted proteins from somatic embryos, plantlets and tuberous roots of cultivar SC8 and separated them by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE).ResultsAnalysis by liquid chromatography-electrospray ionisation-tandem mass spectrometry (LC-ESI-MS/MS) yielded a total of 383 proteins including isoforms, classified into 14 functional groups. The majority of these were carbohydrate and energy metabolism associated proteins (27.2%), followed by those involved in protein biosynthesis (14.4%). Subsequent analysis has revealed that 54, 59, 74 and 102 identified proteins are unique to the somatic embryos, shoots, adventitious roots and tuberous roots, respectively. Some of these proteins may serve as signatures for the physiological and developmental stages of somatic embryos, shoots, adventitious roots and tuberous root. Western blotting results have shown high expression levels of Rubisco in shoots and its absence in the somatic embryos. In addition, high-level expression of alpha-tubulin was found in tuberous roots, and a low-level one in somatic embryos. This extensive study effectively provides a huge data set of dynamic protein-related information to better understand the molecular basis underlying cassava growth, development, and physiological functions.ConclusionThis work paves the way towards a comprehensive, system-wide analysis of the cassava. Integration with transcriptomics, metabolomics and other large scale "-omics" data with systems biology approaches can open new avenues towards engineering cassava to enhance yields, improve nutritional value and overcome the problem of post-harvest physiological deterioration.
| S-EPMC2842255 | biostudies-literature
Project description:Cassava is one of the most versatile tuberous-root crops on Earth. However, the postharvest storage properties of cassava tuberous root mean that it is perishable through a process known as postharvest physiological deterioration (PPD), which seriously affects its starch quality. Therefore, a comprehensive understanding of the transcriptional regulatory activity of cassava against the PPD response is necessary in order to extract key molecular mechanisms related to PPD tolerance. In this study, we found that RYG1 tuberous roots showed delayed PPD compared to those of SC8. In addition, RYG1 roots maintained a more stable cell wall structure after storage than those of SC8. The transcriptome changes in tuberous roots were analyzed for both RYG1 and SC8 after 21 days of storage (SR and SS) compared to fresh (FR and FS) by the RNA-Seq method. The total number of differentially expressed genes (DEGs) in the various comparisons of these four samples ranged from 68 to 3847. Of these, a total of 2008 co-DEGs in SR vs. SS were shared by either SR vs. FR or SS vs. FS. GO and KEGG enrichment analysis revealed that upregulated co-DEGs in SR vs. SS were mainly enriched in photosynthesis, protein processing, hormone and cutin, suberine and wax biosynthesis. By contrast, the downregulated co-DEGs were mainly related to cell wall organization, starch and sucrose metabolism, galactose metabolism, phenylpropanoid biosynthesis, diterpenoid biosynthesis, cysteine and methionine metabolism and flavonoid biosynthesis. The protein-protein interaction (PPI) networks of the co-DEGs showed a complex interaction of genes in different pathways, and 16 hub genes were characterized to have a degree in excess of 15, among which eight genes were associated with photosynthesis. These results provide new information for the study of cassava resistance to PPD and lay a foundation for the further molecular breeding of storage-tolerant cassava varieties.
| S-EPMC9820078 | biostudies-literature
Project description:Mechanisms related to the development of cassava storage roots and starch accumulation remain largely unknown. To evaluate genome-wide expression patterns during cassava tuberization, a 60-mer oligonucleotide microarray representing 20,840 cassava genes was designed to identify differentially expressed transcripts in fibrous root, developing storage root and mature storage root. Using a random variance model and the traditional two-fold change method for statistical analysis, 912 and 3386 differentially expressed genes were identified related to the three different phases. Among 25 significant pathways identified, glycolysis/gluconeogenesis was the most important pathway signature due to its effects on other pathways. Rate-limiting enzymes were identified from each individual pathway, such as pectinesterase, enolase, L-lactate dehydrogenase and aldehyde dehydrogenase in glycolysis/gluconeogenesis, and ADP-glucose pyrophosphorylase, starch branching enzyme and glucan phosphorylase in sucrose and starch metabolism. This study revealed that dynamic changes in at least 16% of the transcriptome, including hundreds of transcription factors, oxidoreductases/transferases/hydrolases, hormone-related genes, and effectors of homeostasis, all of which highlight the complexity of this biological process. The reliability of differentially expressed genes in microarray analysis was further verified by quantitative real-time RT-PCR. The genome-wide transcription analysis facilitates our understanding of the formation of the storage root and deciphers key genes for further cassava improvement. Fibrous roots (FR), developing storage roots (DR) and mature storage roots (MR) were collected for RNA extractions from three independent healthy 4 month-old cassava (cultivar TMS60444) plants in the field .Two RNA samples extracted from stored storage root slices were used as technical repeats (TR) for quality control.
2011-05-13 | E-GEOD-25813 | biostudies-arrayexpress
Project description:Cassava (Manihot esculenta) is valued mainly for high content starch in its roots. Our understanding of mechanisms promoting high starch accumulation in the roots is, however, still very limited. Two field-grown cassava cultivars, Huanan 124(H124) with low root starch and Fuxuan 01(F01) with high root starch, were characterised comparatively at four main growth stages. Changes in key sugars in the leaves, stems and roots seemed not to be strongly associated with the final amount of starch accumulated in the roots. However, when compared with H124, F01 exhibited a more compact arrangement of xylem vascular bundles in the leaf axils, much less callose around the phloem sieve plates in the stems, higher starch synthesis-related enzymatic activity but lower amylase activity in the roots, more significantly up-regulated expression of related genes, and a much higher stem flow rate (SFR). In conclusion, higher starch accumulation in the roots results from the concurrent effects of powerful stem transport capacity highlighted by higher SFR, high starch synthesis but low starch degradation in the roots, and high expression of sugar transporter genes in the stems. A model of high starch accumulation in cassava roots was therefore proposed and discussed.
| S-EPMC4759534 | biostudies-literature
Project description:Synchronized tissue polarization during regeneration or de novo vascular tissue formation is a plant-specific example of intercellular communication and coordinated development. According to the canalization hypothesis, the plant hormone auxin serves as polarizing signal that mediates directional channel formation underlying the spatio-temporal vasculature patterning. A necessary part of canalization is a positive feedback between auxin signaling and polarity of the intercellular auxin flow. The cellular and molecular mechanisms of this process are still poorly understood, not the least, because of a lack of a suitable model system. We show that the main genetic model plant, Arabidopsis (Arabidopsis thaliana) can be used to study the canalization during vascular cambium regeneration and new vasculature formation. We monitored localized auxin responses, directional auxin-transport channels formation, and establishment of new vascular cambium polarity during regenerative processes after stem wounding. The increased auxin response above and around the wound preceded the formation of PIN1 auxin transporter-marked channels from the primarily homogenous tissue and the transient, gradual changes in PIN1 localization preceded the polarity of newly formed vascular tissue. Thus, Arabidopsis is a useful model for studies of coordinated tissue polarization and vasculature formation after wounding allowing for genetic and mechanistic dissection of the canalization hypothesis.
| S-EPMC5030676 | biostudies-literature
Project description:In trees, stem secondary growth depends on vascular cambium proliferation activity and subsequent cell differentiation, in which an auxin concentration gradient across the cambium area plays a crucial role in regulating the process. However, the underlying molecular mechanism for the establishment of auxin concentration is not fully understood. In this study, we identified two function-unknown MADS-box genes, VCM1 and VCM2, which are expressed specifically in the vascular cambium and modulate the subcellular homeostasis of auxin. Simultaneous knockdown of both VCM1 and VCM2 enhanced vascular cambium proliferation activity and subsequent xylem differentiation. Overexpression of VCM1 suppressed vascular cambium activity and wood formation by regulating PIN5 expression, which tuned the soluble auxin concentration in the vascular cambium area. This study reveals the role of VCM1 and VCM2 in regulating the proliferation activity of the vascular cambium and secondary growth by modulating the subcellular auxin homeostasis in Populus. This study demonstrates the function of two MADS-box genes in secondary growth and reveals a molecular mechanism that modulates subcellular auxin homeostasis in the vascular cambium area, which in turn regulates cambium proliferation activity in Populus.
| S-EPMC8553971 | biostudies-literature
Project description:Despite the importance of storage root (SR) organs for cassava and the other root crops yield, their developmental origin is poorly understood. Here we use multiple approaches to shed light on the initial stages of root development demonstrating that SR and fibrous roots (FR) follow different rhizogenic processes. Transcriptome analysis carried out on roots collected before, during and after root bulking highlighted early and specific activation of a number of functions essential for root swelling and identified root-specific genes able to effectively discriminate emerging FR and SR. Starch and sugars start to accumulate at a higher rate in SR before they swell but only after parenchyma tissue has been produced. Finally, using non-destructive computed tomography measurements, we show that SR (but not FR) contain, since their emergence from the stem, an inner channel structure in continuity with the stem secondary xylem, indicating that SR derive from a distinct rhizogenic process compared with FR.
| S-EPMC9314696 | biostudies-literature
Project description:Postharvest physiological deterioration (PPD) is a global challenge in the improvement of cassava value chain. However, how to reduce cassava spoilage and reveal the mechanism of injured cassava storage roots in response to PPD were poorly understood. In the present study, we investigated the activities of antioxidant enzymes of cassava injured storage roots in PPD-susceptible (SC9) and PPD-tolerant (QZ1) genotypes at the time-points from 0h to 120h, and further analyzed their proteomic changes using two-dimensional electrophoresis (2-DE) in combination with MALDI-TOF-MS/MS. Ninety-nine differentially expressed proteins were identified from SC9 and QZ1 genotypes in the pairwise comparison of 24h/0h, 48h/0h, 72h/0h and 96h/0h. Of those proteins were associated with 13 biological functions, in which carbohydrate and energy metabolism related proteins were the biggest amount differential proteins in both genotypes, followed by chaperones, DNA and RNA metabolism, and defense system. We speculated that SOD in combination with CAT activities would be the first line of defense against PPD to support PPD-tolerant cassava varieties. The four hub proteins including CPN60B, LOS2, HSC70-1 and CPN20B, produced from the network of protein-protein interaction, will be the candidate key proteins linked with PPD. This study provides a new clue to improve cassava PPD-tolerant varieties and would be helpful to much better understand the molecular mechanism of PPD of cassava injured storage roots.
| S-EPMC5365129 | biostudies-literature