Banca de DEFESA: GUSTAVO TORRES DOS SANTOS AMORIM

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : GUSTAVO TORRES DOS SANTOS AMORIM
DATE: 30/07/2024
TIME: 13:30
LOCAL: Sala 01 - Programa de Pós-graduação em Fitotecnia/Departamento de Fitotecnia
TITLE:

Genetic diversity based on morphoagronomic and molecular characters aiming to identify periwinkle (Catharanthus roseus [L.] G. Don) genotypes with potential for the production of leaf biomass and alkaloids.

KEY WORDS:

Plant breeding, medicinal plants, multivariate statistics, major descriptors, ISSR molecular marker, HPLC-DAD, vinblastine, minor descriptors.

PAGES: 155
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Fitotecnia
SPECIALTY: Melhoramento Vegetal
SUMMARY:

Periwinkle (Catharanthus roseus [L.] G. Don) is distinguished for being the source of the alkaloids vincristine and vinblastine used in chemotherapy for the conventional treatment of tumors, leukemias and lymphomas. However, these substances occur in low concentrations in the leaves of the species. In this sense, it is essential to develop a genetic improvement program. Given the above, the objective was to understand and estimate the genetic diversity among 79 genotypes of C. roseus based on morphoagronomic variables. Furthermore, the production of dry leaf biomass (BFO_s) was evaluated in 79 periwinkle genotypes and then the best plants for this variable were selected. In such plants, the present research sought to understand the potential for the production of the alkaloids catharanthine (CAT), vindoline (VDL), vincristine (VCR) and vinblastine (VBL), as well as to estimate the molecular diversity verified via ISSR-type DNA markers. Finally, we intended to propose a list of minimum descriptors for periwinkle cultivation. In the first chapter, genetic diversity was accessed through morphoagronomic descriptors. For this, different multivariate analysis strategies were used, such as UPGMA cluster analysis, Anosim, Shannon (H’) and Pielou (J’) diversity indices and relative importance of the variables. In the second chapter, only the best genotypes for the production of BFO_s and positive for the presence of alkaloids continued for chemical analysis. The levels of CAT, VDL, VCR and VBL alkaloids were obtained using HPLC-DAD (High-Performance Liquid Chromatography-Diode Array Detection). Subsequently, the production of alkaloids per plant was estimated (BFO_s x alkaloid content). The genotypes also had their DNA extracted and analyzed using 15 ISSR primers. Molecular diversity was estimated using UPGMA cluster analysis and via H’ and J’ indices. In the third chapter, 15 minimum descriptors were listed, some were quantitative in nature and others were qualitative in nature. Descriptors of a quantitative nature were transformed into multicategorical descriptors, using Sturges' Rule. After combining the matrix of descriptors of qualitative origin and those of quantitative origin, the data was subjected to cluster analysis. The results demonstrated that the genetic diversity of the collection accessed through 18 morphoagronomic descriptors was low to moderate. Of the 79 genotypes evaluated, 15 of them presented BFO_s statistically higher than the population average. Among the 15 superior genotypes for BFO_s, UFRRJ VIN007/14(PAB) was discarded, as it was negative for the presence of alkaloids. In HPLC-DAD it was possible to identify VBL in 13 of the 14 plants analyzed. CAT and VDL were present in all of them and VCR was not detected in any of them. Three genotypes stood out for VBL production. The UFRRJ VIN013/22(PAB) genotype achieved the highest VBL content (0.77 mg/g of BFO_s) and the highest VBL production/plant (13.61 mg). On the other hand, no promising genotypes were observed for CAT and VDL levels. Molecular diversity was high among the genotypes listed as superior for the production of BFO_s, given the genetic distances obtained in the dendrogram, corroborated by the high indices of H' (5.66) and J' (0.96). The 15 minimum descriptors proposed made it possible to distinguish all 77 genotypes analyzed in the dendrogram. This occurred even in less divergent genotypes.

COMMITTEE MEMBERS:
Presidente - 1712769 - PEDRO CORREA DAMASCENO JUNIOR
Interna - 2271445 - BRUNA RAFAELA DA SILVA MENEZES
Externa ao Programa - 2147409 - MARILENE HILMA DOS SANTOS - UFRRJExterna à Instituição - TATIANA DE OLIVEIRA PINTO - UNIFOA
Externa à Instituição - TATIANE DA COSTA BARBE