Banca de DEFESA: MAYARA DE MELLO MARQUES

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : MAYARA DE MELLO MARQUES
DATE: 26/02/2026
TIME: 13:30
LOCAL: PPGFitotecnia
TITLE:

MOLECULAR AND CHEMICAL DIVERSITY AND PERFORMANCE OF PERIWINKLE (Catharanthus roseus [L.] G. Don) GENOTYPES REGARDING THEIR POTENTIAL FOR THE PRODUCTION OF ANTINEOPLASTIC ALKALOIDS: VINBLASTINE, CATHARANTHINE, AND VINDOLINE

KEY WORDS:

Plant breeding; medicinal plants; REML/BLUP; path analysis; ISSR DNA markers; LC-MS.

PAGES: 110
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Fitotecnia
SPECIALTY: Melhoramento Vegetal
SUMMARY:

Periwinkle (Catharanthus roseus), from the family Apocynaceae and probably native to Madagascar, is important for producing alkaloids such as vinblastine (VBL) and vincristine (VCR), which are used in the treatment of lymphomas and leukemias. Since these compounds are not fully synthesized in the laboratory, field cultivation of the plant is essential for extracting the precursors of VBL, catharanthine and vindoline. However, the low yield of alkaloids increases production costs, making breeding programs essential for selecting more productive genotypes. Therefore, this study aimed to evaluate the population and individual performance of periwinkle genotypes based on 18 morphoagronomic variables, including leaf biomass production, over a period of one and a half years. In addition, the potential of the genotypes for the alkaloid contents of vinblastine (VBL) and its precursors, catharanthine (CAT) and vindoline (VDL), from leaves was determined. To this end, the thesis was divided into three chapters. In Chapter 1, 18 morphoagronomic variables, including dry leaf biomass (DLB), were evaluated in 20 genotypes over 18 months at 90-day intervals. The plants were grown in a greenhouse, and each evaluation was considered a replication (repeated over time). Genetic parameters and genotypic values were estimated using REML/BLUP. The individual performance of the genotypes (genotypic values) was also analyzed using BLUP-PCA. The results indicated that leaf-related variables were more sensitive to environmental effects compared to variables related to branches and flowers. Individual repeatability for DLB was moderate, showing that leaf biomass production may vary within and among genotypes. BLUP-PCA analysis demonstrated that high leaf biomass production can be associated with larger leaves and a greater number of branches per plant. In Chapter 2, the same experimental procedures described in Chapter 1 were carried out. However, the mean of each variable was used, estimated from repeated measurements over time. Eleven morphoagronomic variables were analyzed. Path analysis was performed, considering DLB as the main variable. Direct and indirect effects of the remaining variables on DLB were estimated. Leaf area and the mean diameter of primary branches were the variables most strongly associated with DLB, both showing high positive direct effects. The diameter of secondary branches (DSB) was not a good parameter to indicate increases in DLB and did not influence dry leaf biomass on its own. In decreasing order of influence on DLB were petiole length and mean flower length, both with negative coefficients, followed by leaf width, plant height, stem diameter, internode length of primary branches, and total number of branches (TNB), all with positive path coefficients. In Chapter 3, 23 periwinkle genotypes grown in a greenhouse were analyzed using 15 ISSR primers for genomic DNA characterization. Polymorphic information content (PIC) was estimated per locus and per primer. UPGMA clustering based on Jaccard dissimilarity was performed, the optimal number of groups was defined using the kgs algorithm, and population genetic structure was inferred. The contents of vinblastine (VBL), vincristine (VCR), catharanthine (CAT), and vindoline (VDL) were also quantified through ethanolic extraction of dried leaves followed by LC-MS analysis. High polymorphism (95.70%) and primers with medium to high informativeness were observed, although genetic diversity was classified as moderate to low, possibly due to relatedness among the genotypes. The genotypes were grouped into five clusters, with one group comprising 43.48% of them. VCR was not detected, whereas VBL, CAT, and VDL showed wide variation. VBL ranged from 0.0418 to 0.1738 mg/g of dry leaves, and eight promising genotypes were identified for its production, all descendants of the female parents UFRRJ VIN004, UFRRJ VIN044, and UFRRJ VIN005. Given the moderate to low genetic diversity observed, hybridizations among the eight selected genotypes may not be the most efficient strategy to achieve significant gains in VBL content. In this context, the development of inbred families, either from the selected genotypes or from the aforementioned parental lines, appears to be a more promising strategy for increasing VBL production.

COMMITTEE MEMBERS:
Presidente - 1712769 - PEDRO CORREA DAMASCENO JUNIOR
Externo ao Programa - 1809123 - ANDRE MARQUES DOS SANTOS - UFRRJExterna ao Programa - 2147409 - MARILENE HILMA DOS SANTOS - UFRRJExterno à Instituição - EDILSON ROMAIS SCHMILDT - UFES
Externa à Instituição - TATIANA DE OLIVEIRA PINTO - UNIFOA