Morphological Traits and Nuclear Genetic Diversity of Coptis sp. in Hoang Lien National Park, Lao Cai Province, Vietnam

Coptis is a medicinal plant genus in the Ranunculaceae family, and is also known as “Hoang Lien” in Vietnamese. It is a perennial herb that grows in some regions of the world. However, Coptis is endangered and faces global threats. This study aimed to characterize some main morphological characteristics and performed a phylogenetic analysis of 11 samples of Coptis sp. collected from Hoang Lien National Park using nuclear DNA sequence analyses. All sample species have unique morphological traits with distinct yellow rhizomes and basal leaves with five segments. The petiole measures 13-25 cm and is smooth, while the leaf blade is ovate, ranging from 7 to 15.5 cm in length and 5.5 to 14 cm in width. The leaves are subleathery, glabrous on the underside, and sparsely puberulous on the veins on the upper side. The molecular characterization of Coptis sp. genotypes was determined by ITS markers. The length of the ITS1-ITS2 sequences varied from 363 to 371 nucleotides. The average nucleotide composition was 17.11% A, 31.25% C, 32.247% G and 19.41% T, respectively. The comparison with the GenBank database showed that the samples had 95.71- 96.37% similarity with the species Coptis quinquesecta. The genetic distance among the 11 Coptis samples fluctuated from 0.00 to 0.017. A neighbor-joining tree was constructed to show the genetic relationships among Coptis samples. The results indicated that this endangered species had low levels of genetic diversity. The study has provided valuable information for genetic-based conservation of this rare endemic species and suggested some conservation strategies

Genome-wide association study of a panel of vietnamese rice landraces reveals new QTLs for tolerance to water deficit during the vegetative phase

Background: Drought tolerance is a major challenge in breeding rice for unfavorable environments. In this study, we used a panel of 180 Vietnamese rice landraces genotyped with 21,623 single-nucleotide polymorphism markers to perform a genome-wide association study (GWAS) for different drought response and recovery traits during the vegetative stage. These landraces originate from different geographical locations and are adapted to different agrosystems characterized by contrasted water regimes. Vietnamese landraces are often underrepresented in international panels used for GWAS, but they can contain original genetic determinants related to drought resistance. Results: The panel of 180 rice varieties was phenotyped under greenhouse conditions for several drought-related traits in an experimental design with 3 replicates. Plants were grown in pots for 4 weeks and drought-stressed by stopping irrigation for an additional 4 weeks. Drought sensitivity scores and leaf relative water content were measured throughout the drought stress. The recovery capacity was measured 2 weeks after plant rewatering. Several QTLs associated with these drought tolerance traits were identified by GWAS using a mixed model with control of structure and kinship. The number of detected QTLs consisted of 14 for leaf relative water content, 9 for slope of relative water content, 12 for drought sensitivity score, 3 for recovery ability and 1 for relative crop growth rate. This set of 39 QTLs actually corresponded to a total of 17 different QTLs because 9 were simultaneously associated with two or more traits, which indicates that these common loci may have pleiotropic effects on drought-related traits. No QTL was found in association with the same traits in both the indica and japonica subpanels. The possible candidate genes underlying the quantitative trait loci are reviewed. Conclusions: Some of the identified QTLs contain promising candidate genes with a function related to drought tolerance by osmotic stress adjustment

Evaluation of Ursolic Acid as the Main Component Isolated from Catharanthus Roseus against Hyperglycemia

ABSTRACT. Ursolic acid with large amount (0.67% of dried plant weight) along with 7 compounds, namely as spatozoate (1), kaurenoic acid (2), ursonic acid (3), 3-hydroxy-11-ursen-28,13-olide (4), ursolic acid (5), vindoline (6) and mixture of β-sitosterol and stigmasterol were isolated from dichloromethane and ethyl acetate extracts which have shown anti-glucosidase activity of the whole plant of C.roseus. Some isolated compounds and their derivatives were also tested for anti-glucosidase and cytotoxicity.Ursolic acid was examined for hypoglycemic activity in alloxan-induced diabetic mice with dose of 200 and 300 mg/kg/day, respectively. The results have shown that the blood glucose level were reduced by 45.75% and 51.31% to compare with the control group. This study has confirmed that the main component of Vietnamese C. roseus has had significant anti-hyperglycemia activity

Genome-wide Association Study of apanel of Vietnamese Rice Landraces Reveals New QTLs for tolerance to water deficit during the vegetative phase

International audienceBackground Drought tolerance is a major challenge in breeding rice for unfavorable environments. In this study, we used a panel of 180 Vietnamese rice landraces genotyped with 21,623 single-nucleotide polymorphism markers to perform a genome-wide association study (GWAS) for different drought response and recovery traits during the vegetative stage. These landraces originate from different geographical locations and are adapted to different agrosystems characterized by contrasted water regimes. Vietnamese landraces are often underrepresented in international panels used for GWAS, but they can contain original genetic determinants related to drought resistance. Results The panel of 180 rice varieties was phenotyped under greenhouse conditions for several drought-related traits in an experimental design with 3 replicates. Plants were grown in pots for 4 weeks and drought-stressed by stopping irrigation for an additional 4 weeks. Drought sensitivity scores and leaf relative water content were measured throughout the drought stress. The recovery capacity was measured 2 weeks after plant rewatering. Several QTLs associated with these drought tolerance traits were identified by GWAS using a mixed model with control of structure and kinship. The number of detected QTLs consisted of 14 for leaf relative water content, 9 for slope of relative water content, 12 for drought sensitivity score, 3 for recovery ability and 1 for relative crop growth rate. This set of 39 QTLs actually corresponded to a total of 17 different QTLs because 9 were simultaneously associated with two or more traits, which indicates that these common loci may have pleiotropic effects on drought-related traits. No QTL was found in association with the same traits in both the indica and japonica subpanels. The possible candidate genes underlying the quantitative trait loci are reviewed. Conclusions Some of the identified QTLs contain promising candidate genes with a function related to drought tolerance by osmotic stress adjustment