ABSTRACT
Leaf blight outbroke in Rehmannia glutinosa plantation in Wenxian county, Henan province in 2019. R. glutinosa plants with diseased leaves were collected from the plantation, and three strains were isolated from the diseased leaf samples. Pathogenicity test, morphological observation, and phylogenetic analysis of ITS, EF1-α, and Tub suggested that they were respectively Fusarium proliferatum, F. oxysporum, and F.acuminatum. Among them, F. acuminatum, as a pathogen of R. glutinosa leaf disease, had never been reported. To clarify the biological characteristics of F. acuminatum, this study tested the influence of light, pH, temperature, medium, carbon source, and nitrogen source on the mycelial growth rate of the pathogen during a 5-day culture period, and explored the lethal temperature. The results showed that the mycelia grew well under the photoperiod of 12 h light/12 h darkness, at 5-40 ℃(optimal temperature: 25 ℃), at pH 4-11(optimal pH: 7.0), on a variety of media(optimal medium: oatmeal agar), and in the presence of diverse carbon and nitrogen sources(optimal carbon source: soluble starch; optimal nitrogen source: sodium nitrate). The lethal temperature was verified to be 51 ℃(10 min). The conclusion is expected to lay a scientific basis for diagnosis and control of R. glutinosa leaf diseases caused by F. acuminatum.
Subject(s)
Carbon , Nitrogen , Phylogeny , RehmanniaABSTRACT
The present study analyzed the effects of planting density on the development, quality, and gene transcription characte-ristics of Rehmannia glutinosa using 85-5 and J9 as materials with three planting densities of 5 000, 25 000, and 50 000 plants/Mu(1 Mu≈667 m~2). The agronomic characteristics of leaves and tuberous roots, the content of catalpol and acteoside, and the changes of gene expression were determined. The results showed that the leaf size, the diameter of tuberous root, leaf biomass, tuberous root number, and tuberous root biomass per plant at low density were significantly higher than those of medium and high densities. The content of catalpol and acteoside in leaves was higher at high density. The content of catalpol in tuberous roots was higher at low density, and the change trend was similar to that in leaves, while the content of acteoside in tuberous roots was higher at high density. Transcriptome analysis found that about 1/2 of the expansin genes could change regularly in response to density treatment, which was rela-ted to the development of tuberous roots. The change trend of the gene expression of multiple catalytic enzymes involved in the biosynthesis of catalpol and acteoside was consistent with that of their content, which was presumedly involved in the accumulation and regulation of density-responsive medicinal components. Based on the analysis of the development, medicinal components, and gene expression characteristics of R. glutinosa at different densities, this study is expected to provide an important basis for regulating the quality and yield of medicinal materials of R. glutinosa by managing the planting density.
Subject(s)
Gene Expression Profiling , Plant Leaves/genetics , Plant Roots/genetics , Rehmannia/genetics , Transcription, GeneticABSTRACT
Tyrosine decarboxylase (TyrDC) is an important enzyme in the secondary metabolism of several plant species, and was hypothesized to play a key role in the biosynthesis of phenylethanoid glycosides. Based on the transcriptome data, we cloned the full-length cDNA (GenBank accession NO. KU640395) of RgTyDC gene from Rehmannia glutinosa, and then performed bioinformatic analysis of the sequence. Further, we detected the expression pattern in different organs and hair roots treated with four elicitors by qRT-PCR. The results showed that the full length of RgTyDC cDNA was 1 530 bp encoding 509 amino acids. The molecular weight of the putative RgTyDC protein was about 56.6 kDa and the theoretical isoelectric point was 6.25. The RgTyDC indicated the highest homology with Sesamum indicum SiTyDC and Erythranthe guttata EgTyDC, both of them were reached 88%. RgTyDC highly expressed in R. glutinosa leaf, especially in senescing leaf, and rarely expressed in tuberous root. After the treatment of SA and MeJA, the relative expression level of RgTyDC mRNA was substantially increased. The results provide a foundation for exploring the molecular function of RgTyDC involved in phenylethanoid glycosides biosynthesis.
ABSTRACT
<p><b>OBJECTIVE</b>Botanical characters of germplasm resources of Dioscorea were observed and compared, which could to offer reference for its genetic improvement, germplasm resource identification and classification.</p><p><b>METHOD</b>Based on field cultivation, twenty-four morphological traits of ninety-four Dioscorea germplasm resources were observed or determined. And the morphological differences among germplasm resources were compared by principal component analysis and cluster analysis.</p><p><b>RESULT</b>There were ample morphological diversity in the twenty-four traits, in especially in leaf size and tuber characters of the ninety-four Dioscorea germplasm resources. The first seven principal components which accounted for 80. 957% of total variance were extracted from the principal component analysis. The ninety-four germplasm resources could be divided into four clusters, which belonging to Dioscorea opposite, D. persimili, D. fordii and D. alata respectively.</p><p><b>CONCLUSION</b>There were large morphological variation among germplasm resources on Dioscorea. Identification of germplasm resources of Dioscorea should focus on leaf size and tuber characters.</p>