Francisco J. Espinosa-García

Plant secondary metabolite diversity as a resistance trait against insects: a test with Sitophilus granarius (Coleoptera: Curculionidae) and seed secondary metabolites

A hypothesis is tested about the functioning of plant secondary metabolite diversity taking into account the role of concentration of mixtures or single compounds: a high diversity secondary metabolite mixture in high concentration provides a more effective protection against herbivores than single compounds or low diversity mixtures in both low and high concentrations. Additionally the role of two unusual secondary metabolites for a weevil when they are incorporated in its diet is explored. Number of eggs laid and diet consumption are measured in the granary weevil Sitophilus granarius exposed to cereal and non-cereal secondary metabolites incorporated in artificial diets to test the hypothesis. Artificial diets had one, two, four or six compounds. The mixtures or single compounds were offered simultaneously to the weevils in concentrations ranging from 0.05 to 5mg g−1 in a multiple choice experiment. Low oviposition in high concentration six compounds mixture supported the hypothesis. However, low oviposition in a low concentration mixture of four compounds suggests that a moderate diversity may be equally functional in low and high concentrations. Diet consumption by the weevil was not affected by concentration but an increasing number of compounds in the diet reduced it slightly but significantly. The unusual secondary metabolites for the weevil were less or equally effective reducing oviposition and consumption as usual compounds did.

Phytoalexins, Resistance Traits, and Domestication Status in Phaseolus coccineus and Phaseolus lunatus

Resistance to pathogenic fungi and the isoflavonoids that confer such resistance capabilities were studied in two systems of wild and cultivated Phaseolus spp. seedlings. Results for P. coccineus show a gradient in isoflavonoid diversity with pathogen resistance high in wild varieties and low in cultivated ones. P. lunatus varieties showed the same trend in resistance and cyanogenic capacity, but not in isoflavonoid diversity. It is suggested that the effectiveness of the phytoalexin natural mixture depends more on its diversity than its total levels in seedlings.

Diversity and Communities of Foliar Endophytic Fungi from Different Agroecosystems of Coffea arabica L. in Two Regions of Veracruz, Mexico

Over the past 20 years, the biodiversity associated with shaded coffee plantations and the role of diverse agroforestry types in biodiversity conservation and environmental services have been topics of debate. Endophytic fungi, which are microorganisms that inhabit plant tissues in an asymptomatic manner, form a part of the biodiversity associated with coffee plants. Studies on the endophytic fungi communities of cultivable host plants have shown variability among farming regions; however, the variability in fungal endophytic communities of coffee plants among different coffee agroforestry systems is still poorly understood. As such, we analyzed the diversity and communities of foliar endophytic fungi inhabiting Coffea arabica plants growing in the rustic plantations and simple polycultures of two regions in the center of Veracruz, Mexico. The endophytic fungi isolates were identified by their morphological traits, and the majority of identified species correspond to species of fungi previously reported as endophytes of coffee leaves. We analyzed and compared the colonization rates, diversity, and communities of endophytes found in the different agroforestry systems and in the different regions. Although the endophytic diversity was not fully recovered, we found differences in the abundance and diversity of endophytes among the coffee regions and differences in richness between the two different agroforestry systems of each region. No consistent pattern of community similarity was found between the coffee agroforestry systems, but we found that rustic plantations shared the highest number of morphospecies. The results suggest that endophyte abundance, richness, diversity, and communities may be influenced predominantly by coffee region, and to a lesser extent, by the agroforestry system. Our results contribute to the knowledge of the relationships between agroforestry systems and biodiversity conservation and provide information regarding some endophytic fungi and their communities as potential management tools against coffee plant pests and pathogens.

Effects of domestication and agronomic selection on phytoalexin antifungal defense in Phaseolus beans

Systems of wild and cultivated relatives are good experimental systems to test chemical defense theory because they provide closely related varieties that differ in discrete traits. To determine the relationship between resistance and chemical defense diversity among wild, landrace and cultivar accessions of Phaseolus vulgaris, we measured resistance to fungal infection in laboratory and field experiments, quantified phytoalexin diversity, and assessed the effectiveness of phytoalexin mixtures extracted from live tissue. Results show a gradient of resistance to fungal infections between wild, landrace and cultivar varieties. In the laboratory, wild seedlings were more resistant (93% non-infected) than landrace seedlings (80% non-infected) and modern cultivar seedlings (68% non-infected). Under field conditions wild seedlings were more resistant (97% non-infected) than cultivar seedlings (71% non-infected). Wild seedlings presented the highest phytoalexin diversity (H′ = 1.11), while those of the landrace presented an intermediate level (H′ = 0.97) and cultivar seedlings presented the lowest diversity (H′ = 0.93). No differences were found in total concentrations. The in vitro inhibitory properties on hyphal growth of the isoflavonoid mixtures produced by individual seedlings showed a similar trend. Our results are consistent with similar gradients in other species of Phaseolus beans and resistance to Colletotrichum sublineolum in sorghum.

Sesquiterpene lactones from Mikania micrantha and Mikania cordifolia and their cytotoxic and anti-inflammatory evaluation.

The guaianolide 8-epi-mikanokryptin (1) and the melampolide 11Hβ-11,13-dihydromicrantholide (2) along with known sesquiterpene lactones (3-13) and other constituents were isolated from the aerial parts of different populations of Mikania micrantha and Mikania cordifolia collected in several states of Mexico. The relative and absolute configurations of 1 were determined by X-ray diffraction and CD analysis, respectively. Considering the (1)H and (13)C NMR chemical shift similarities and the H-H coupling constant values, a [(1)D(14), (15)D5] conformation was established for micrantholides (2, 8-13). We tested nearly all the sesquiterpene lactones for antiproliferative activity in human cancer cell lines, and they exhibited moderate activity. Additionally, in a mouse ear model of edema induced by TPA, the anti-inflammatory activities were marginal.

Ethnobotanical, morphological, phytochemical and molecular evidence for the incipient domestication of Epazote (Chenopodium ambrosioides L.: Chenopodiaceae) in a semi-arid region of Mexico

Use and management of wild and weedy species may involve artificial selection, which can determine morphological, physiological, reproductive, and genetic divergences between wild and managed populations, resulting in the initial or incipient phases of plant domestication. In this study we combined ethnobotanical, morphological, phytochemical and genetic information for analyzing differences between managed and unmanaged populations of the Mexican edible weed, Epazote (Chenopodium ambrosioides L.), in Santa María Tecomavaca, Oaxaca, a rural community within the Tehuacán-Cuicatlán Biosphere Reserve, Mexico. Our hypothesis was that differences in morphology (e.g. leave dimensions and density of pubescence), phytochemistry (e.g. flavor, odor, and amount of strong scented and toxic compounds) and/or molecular genetic markers, between managed and wild populations of Epazote in Santa María Tecomavaca, would indicate that managed populations have been and/or are under a process of incipient domestication. Our results revealed the existence in the study area of morphological variants associated with a gradient of management intensity, which involved apparent improved palatability correlated with a lowering of chemical defense. Most remarkably, we found agreement in the groupings defined by the cluster analyses of morphological and genetic data. Although Epazote is considered a weed or, at best, a minor crop, the results from four lines of evidence (cultural differentiation patterns, gigantism, reduction in chemical defenses, toxic compounds and inheritance of adaptive traits) suggest the existence of an incipient domestication process in the study zone.

Cadinane-Type Sesquiterpenoids from Heterotheca inuloides: Absolute Configuration and Anti-inflammatory Activity

Eight cadinane-type sesquiterpenoids (1-8) together with some triterpenoids, flavonoids, and sterols were isolated from the aerial parts of Heterotheca inuloides. The structures of the new compounds (1-4) were elucidated on the basis of extensive 1D and 2D NMR spectroscopic data analysis. The structures of the new (1-3) and the known (5-7) sesquiterpenoids were confirmed by X-ray crystallography. The absolute configurations of metabolites 2-5 were determined by comparing their experimental and calculated electronic circular dichroism spectra and confirmed via refinement of the Flack parameter using anomalous X-ray scattering from the oxygen atoms and chemical correlation methods. The sesquiterpenoids were evaluated for their anti-inflammatory potential by applying the TPA-induced mouse ear edema model. The results revealed that some of these metabolites exhibit moderate anti-inflammatory activity. At a dose of 228 μg/ear compound 1 showed 43.14 ± 8.09% inhibition on ear edema, indicating an IC50 > 228 μg/ear.

Geographical Patterns in Native and Exotic Weeds of Mexico1

Abstract We compared distributions of native nonweed, native weed, and exotic weed species based on a weed checklist for Mexico and for each of the 32 federal states. The national checklist contains 2,197 native and 617 exotic weed species. We calculated floristic similarity between states for native and exotic weeds and grouped the state floristic similarities by cluster analysis. The exotic and native weed species show different patterns both for distribution size and for geographic groupings. About 64% of the exotic species occur in eight or less states, whereas 36% of the native weed species occur in this limited range. Only 5.3% of the exotic species but 8.5% of the natives are recorded from 25 or more states. Native nonweed species have even more limited distributions than exotic weeds. The cluster analysis shows that the groupings based on the native weed flora are mostly coherent with general phytogeographical classifications. The grouping of the states for exotic weeds was different, and we propose that it may be related to climatic factors (particularly extreme minimum temperatures) and to management. The data do not support the hypothesis that exotic species have a superior, more general-purpose genotype than members of a well-developed, native weed flora. Additional index words: Invasive plants, weed distribution, weed phytogeography.

Mexican Arnica (Heterotheca inuloides Cass. Asteraceae: Astereae): Ethnomedical uses, chemical constituents and biological properties.

ETHNOPHARMACOLOGICAL RELEVANCE Heterotheca inuloides Cass. (Asteraceae) has been traditionally used to treat a wide range of diseases in Mexico in the treatment of rheumatism, topical skin inflammation, muscular pain colic, and other painful conditions associated with inflammatory processes, additionally has been used to treat dental diseases, and gastrointestinal disorders. This species has also been used for the treatment of cancer and diabetes. This review provides up-to-date information on the botanical characterization, traditional uses, chemical constituents, as well as the biolological activities of H. inuloides. MATERIAL AND METHODS A literature search was conducted by analyzing the published scientific material. Information related to H. inuloides was collected from various primary information sources, including books, published articles in peer-reviewed journals, monographs, theses and government survey reports. The electronic search of bibliographic information was gathered from accepted scientific databases such as Scienfinder, ISI Web of Science, Scielo, LILACS, Redalyc, Pubmed, SCOPUS and Google Scholar. RESULTS To date, more than 140 compounds have been identified from H. inuloides, including cadinane sesquiterpenes, flavonoids, phytosterols, triterpenes, benzoic acid derivatives, and other types of compounds. Many biological properties associated with H. inuloides. Many studies have shown that the extracts and some compounds isolated from this plant exhibit a broad spectrum of biological activities such as antioxidant, antitumor, anti-inflammatory, cytotoxic, and chelating activities, as well as insecticidal and phytotoxic activity. To date, reports on the toxicity of H. inuloides are limited. CONCLUSIONS A comprehensive analysis of the literature obtained through the above-mentioned sources confirmed that ethnomedical uses of H. inuloides have been recorded in Mexico to treat rheumatism, pain, and conditions associated with inflammatory processes. Pharmacological studies have demonstrated the activity of certain compounds associated with the traditional use of the plant such as the anti-inflammatory and cytotoxic activities of the species. The available literature showed that cadinene sesquiterpenes are the major bioactive components of H. inuloides with potential pharmacological activities. Further investigations are needed to fully understand the mode of action of the major active constituents.

Ecological Niche Modeling of Invasive Plant Species According to Invasion Status and Management Needs: The Case of Chromolaena odorata (Asteraceae) in South Africa

ABSTRACT The management of invasive plant species (IPS) requires knowledge of areas susceptible to invasion and the origin of the invasive biotypes. Ecological niche models (ENMs) are useful for these purposes, but modeling results depend on the data sources. We propose a synthetic approach to determine the selection of data source areas considering the invasion status of an IPS and management objectives to deal with the IPS. We assessed the importance of data source for ENMs and their projections to invasive areas using Chromolaena odorata, a Neotropical weed, in South Africa where this IPS is invading. We used MaxEnt to perform ENMs using different datasets from C. odoratas native range and from South Africa. We employed reciprocal ENM projections to find the probable native region of the plants invading South Africa. ENMs varied depending on the native area selected as the hypothetical invasion source. The modeling approach using worldwide data was most appropriate for prevention purposes, whereas the modelling approach using data from the Americas was most suitable for estimating invasion-susceptible areas in South Africa. The South African ENM was useful for reciprocal modelling but not for prediction of areas susceptible to invasion. ENM projections from the Americas to South Africa and vice-versa identified two native areas as possible invasion sources (northern Mexico and southern tropical South America). Their concordance with the South African ENM can be useful to search for natural enemies of C. odoratas and to reinforce the identification of invasion-susceptible areas in South Africa. We suggest that the various ENM obtained with the synthetic approach in modeling with different data sources for C. odorata cover the scenarios that depend on management purpose and invasion status for this weed.