Diversity in Vitex negundo L.: morphological genetic, histochemical and molecular characterization

Lagundi (Vitex negundo L.) is one of the top ten medical plants being promoted by the Department of Health here in the Philippines. This lecture aims to elucidate the diversity in Vitex negundo L. in the Philippines through morphological, genetic, phytochemical and molecular characterization. It is an offshoot of the preliminary research done since 2010 that started on the genetic profiling of Lagundi using molecular biology markers, i.e. inter-sample sequence repeats (ISSR) to assess the genetic variations in V. negundo found in the fifteen geographic locations in the Philippines. Morphologically, leaf characterization of ten V. negundo germplasm collections from National Plant Genetics Research Laboratory (NPGRL), Institute of Plant Breeding, UP Los Banos, Philippines based on several leaf characters, such leaf types, shape, margin, apex, base, adaxial and abaxial surfaces were characterized. Moreover, foliar trichome anatomy, micromorphology and histochemistry were also evaluated. Based on ISSR markers, there was a common locus or pattern of bands that is present in all samples from the fifteen geographic locations that can be attributed to the fact that all samples belong from the fifteen geographic locations that can be attributed to the fact that all samples belong to one species. The samples also exhibited a great number of polymorphisms suggesting genetic variation found within the V. negundo species that can be attributed to several factors like climate type, tapography and soil type. The leaf characters and their morphometric analysis have shown to be essential in elaborating the variations found in the ten germplasm collection where two groups have been formed, one with lanceolate leaves and the other a non-lanceolate leaf shape. Additional, intraspecific variations of foliar trichome morphology that can be classified into six morphotypes were found evident in the ten accessions used in the study. The presence of both grandular and non-gradular trichomes as well as their respective types in all accessions suggests that trichome type is a stable character wiyhi the V. negundo accessions. Moreover, foliar trichome histochemistry was carried out to detect the presence or absence of lipid, carbohydrates and secondary metabolites such as terpenes, phenolic compounds, flavonoids and alkaloids. It showed the qualitative variations in terms of contents and localization of the major chemical compounds among the tested V. negundo accessions and between the types of trichomes. The phytochemical variation among accessions of similar species is highly attributed to several factors ranging from genetic, biotic abiotic environmental factors influencing the amount of metabolites present in a plant species and evan in different plant parts. The results revealed from the aforementioned studies on genetic diversity, leaf characterization and morphometrics, and foliar trichome micromorphology and histochemistry provided baseline information an can be a helpful tool in resolving taxonomic discrepancies in V. negundo. It is evident that the phenolic pasticity in V. negundo is high due its adaptation to changes in the environment, thus, it is probable that the active compounds will be different in quantity and potency for each morphotypes/variants. with regard to the future directions for V. negundo research, the availability of a biorepository of medicinal plants is necessary. Biorespository collects, stores, stores, maintains, distributes biological materials of different forms and their associated information for use in future researches. Lagundi samples and other medicinal plants could be deposited in the forms of seeds, extracts, DNA or RNA, and even live plants with their corresponsing vital information. Furthermore, molecular and biotechnological approaches such DNA barcoding will help in the rapid and accurate species identification. Since medicinal plants, such as V. negundo contain numerous active ingredients and complex molecules that are yes to be identified and analyzed, OMIC technologies (i.e. genomics, transcriptomics, preteomics, metabolics, phenomics) are promising and powerful tools that can be used in identyfing genes, proteins, metabolites, mechanics and physiological actions of medicinal plat species. Lastly, because there are also the threats or losing the vast potential sources of our medicinal plants worldwide due to increasing human population as well as as plant consumption. It is imperative to develop breeding strategies and methodologies concerning the conservation and sustainable usage of medicinal plant resources.