Search Results (5)

Taro (Colocasia esculenta (L.) Schott) is the fifth largest rhizome crop, and it is widely distributed in tropical and subtropical areas in the world. Vegetative propagation with virus-infected corms can lead to cultivar degradation, yield decline, and quality deterioration. In this study, the shoot apical meristems excised from taro corms infected with dasheen mosaic virus, which belongs to the genus Potyvirus in the family Potyviridae, were cultured and treated with exogenous abscisic acid and high sucrose concentrations to induce micro-corm formation. Subsequently, candidate genes involved in micro-corm expansion were screened via transcriptome sequencing analysis. The results revealed that the shoot apical meristems could grow into adventitious shoots on the medium 1 mg/L 6-benzylaminopurine + 0.3 mg/L 1-naphthaleneacetic acid, and reverse transcription–polymerase chain reaction detection indicated that dasheen mosaic virus had been successfully eliminated from the test-tube plantlets. Moreover, 8% sucrose or 3% sucrose + 5 μM abscisic acid likewise induced taro corm formation, and genes related to cell division and the cell cycle, as well as starch and sucrose metabolism pathways, were significantly enriched during taro corm expansion. Furthermore, the cyclin-dependent kinases genes, cell cycle protein kinase subunit genes, and cyclin B2 genes, which are related to cell division and the cell cycle, were upregulated with abscisic acid treatment on the 3rd day. The sucrose synthase genes, β-amylase genes, glycogen branching enzyme genes, and soluble starch synthase genes, which are related to starch and sucrose metabolism, were upregulated on the 15th day, indicating that cell division largely occurs during taro corm formation, whereas carbohydrates are synthesized during taro corm expansion. Full article

The global significance of Colocasia esculenta, a tuber crop rich in nutritional value and starch, prompts further investigation into its corm development. Background: Previous studies have focused on starch accumulation within the tubers, yet the genetic and proteomic basis of corm expansion remains largely unexplored. This study aims to elucidate the key genes and proteins involved in this process. Methods: We selected ‘Lipu Taro No.1’ and conducted a longitudinal starch content analysis, full-length transcriptome sequencing, and a proteomic analysis during three distinct stages of corm development. Results: Our findings reveal a significant increase in both amylose and amylopectin contents as the corm develops, indicating the temporal regulation of starch biosynthesis. The integration of transcriptome and proteomic data identified differentially expressed genes and proteins associated with starch and sucrose metabolism, as well as plant hormone signal transduction. Conclusions: This study delineates a temporal gene expression pattern that is crucial for starch synthesis and provides insights into the regulatory mechanisms controlling corm expansion and starch deposition, offering valuable references for future molecular breeding strategies to enhance taro yield and quality. Full article

Taro (Colocasia esculenta (L.) Schott) is a tropical tuber crop whose underground corms are used as an important staple food. However, due to a lack of molecular markers, the genetic diversity, germplasm identification, and molecular breeding of taro are greatly limited. In this study, high-density InDel-SSR molecular markers covering the whole genome were developed based on the resequencing data of taro core germplasm. A total of 1,805,634 InDel-SSR loci were identified, and 219 highly polymorphic markers with an average polymorphism information content PIC value of 0.428 were screened. Furthermore, a genetic diversity analysis of 121 taro germplasm resources was conducted based on 219 markers, dividing the resources into three groups. In addition, an association analysis showed that, of the multiple InDel-SSR markers, g13.52 and g12.82 were significantly associated with leaf area and average cormel weight, respectively; the candidate genes CeARF17 (EVM0014444) and CeGA20ox (EVM0001890) were related to cormel expansion; and we excavated the candidate genes CeXXT2 (EVM0016820) and CeLOG1 (EVM0017064), which regulate leaf development. The InDel-SSRs and candidate genes identified in this study are expected to provide important support for genetically improving and breeding new varieties of taro. Full article

Soil is the base for conventional plant growth. The rhizosphere pressure generated from soil compaction shows a dual effect on plant growth in agricultural production. Compacted soil leads to root growth stagnation and causes bending or thickening, thus affecting the growth of aboveground parts of plants. In arrowhead (Sagittaria trifolia L.), the corms derived from the expanded tips of underground stolons are its storage organ. We found that the formation of corms was significantly delayed under hydroponic conditions without rhizosphere pressure originating from soil/sand. In the initial stage of corm expansion, the anatomic structure of arrowhead corm-forming parts harvested from hydroponics and sand culture was observed, and we found that the corm expansion was derived from cell enlargement and starch accumulation. Comparative transcriptome analysis indicated that the corm expansion was closely related to the change in endogenous hormone levels. Endogenous abscisic acid and salicylic acid concentrations were significantly increased in sand-cultured corms. Higher ethylene and jasmonic acid contents were also detected in all arrowhead samples, demonstrating that these hormones may play potential roles in the rhizosphere pressure response and corm expansion. The expression of genes participating in hormone signaling could explain the rising accumulation of certain hormones. Our current results draw an extensive model to reveal the potential regulation mechanism of arrowhead corm expansion promoted by rhizosphere pressure, which will provide important references for further studying the molecular mechanism of rhizosphere pressure modulating the development of underground storage organs in other plants. Full article

Real-time quantitative PCR (RT-qPCR) is a method with high sensitivity and convenience that has been extensively used to analyze the expression level of target genes. A reference gene with a highly stable expression is required to ensure the accuracy of experimental results. However, the report on appropriate reference genes in arrowheads (Sagittaria trifolia) is still limited. In this study, eight candidate reference genes (ACT5, UBQ, GAPDH, CYP, NAC, IDH, SLEEPER and PLA) were selected. The candidate genes were employed in a RT-qPCR assay in different tissues at different developmental stages of the same tissue (including corm, leaf and leafstalk) in arrowheads. Five statistical algorithms, GeNorm, NormFinder, BestKeeper, delta cycle threshold (ΔCt) and RefFinder, were used to evaluate the stability of these genes’ expressions in order to identify the appropriate reference genes. The results showed that UBQ was the optimum reference gene in leaf, leafstalk, root, stolon and corm, IDH exhibited the most stable expression during the expansion of corm, UBQ and PLA were the most stable reference genes in developmental stages of leaf and leafstalk, respectively. Finally, the reliability of reference genes was further confirmed by the normalization of PDS and EXP1 genes under different arrowhead tissues and developmental stages of corm, respectively. This study constitutes important guidance for the selection of reliable reference genes for analyzing the tissue- and developmental-stage-specific expression of genes in arrowheads. Full article