Metagenomic Survey of the Highly Polyphagous Anastrepha ludens Developing in Ancestral and Exotic Hosts Reveals the Lack of a Stable Microbiota in Larvae and the Strong Influence of Metamorphosis on Adult Gut Microbiota

We studied the microbiota of a highly polyphagous insect, Anastrepha ludens (Diptera: Tephritidae), developing in six of its hosts, including two ancestral (Casimiroa edulis and C. greggii), three exotic (Mangifera indica cv. Ataulfo, Prunus persica cv. Criollo, and Citrus x aurantium) and one occasional host (Capsicum pubescens cv. Manzano), that is only used when extreme drought conditions limit fruiting by the common hosts. One of the exotic hosts (“criollo” peach) is rife with polyphenols and the occasional host with capsaicinoids exerting high fitness costs on the larvae. We pursued the following questions: (1) How is the microbial composition of the larval food related to the composition of the larval and adult microbiota, and what does this tell us about transience and stability of this species’ gut microbiota? (2) How does metamorphosis affect the adult microbiota? We surveyed the microbiota of the pulp of each host fruit, as well as the gut microbiota of larvae and adult flies and found that the gut of A. ludens larvae lacks a stable microbiota, since it was invariably associated with the composition of the pulp microbiota of the host plant species studied and was also different from the microbiota of adult flies indicating that metamorphosis filters out much of the microbiota present in larvae. The microbiota of adult males and females was similar between them, independent of host plant and was dominated by bacteria within the Enterobacteriaceae. We found that in the case of the “toxic” occasional host C. pubescens the microbiota is enriched in potentially deleterious genera that were much less abundant in the other hosts. In contrast, the pulp of the ancestral host C. edulis is enriched in several bacterial groups that can be beneficial for larval development. We also report for the first time the presence of bacteria within the Arcobacteraceae family in the gut microbiota of A. ludens stemming from C. edulis. Based on our findings, we conclude that changes in the food-associated microbiota dictate major changes in the larval microbiota, suggesting that most larval gut microbiota is originated from the food.

Does the African Citrus psyllid, Trioza erytreae (Del Guercio) (Hemiptera: Triozidae), Represent a Phytosanitary Threat to the Citrus Industry in Mexico?

The African citrus psyllid, Trioza erytreae (Del Guercio) (Hemiptera: Triozidae), is a vector of Candidatus Liberibacter africanus (CLaf), a pathogen that causes huanglongbing (HLB) in Africa. Trioza erytreae has invaded areas of Asia and Europe and has threatened citrus production due to its biological habits and the transmission of CLaf. Mexico is a country where citrus production has a vital role from the economic and social point of view. Therefore, ecological niche modeling (ENM) was used to determine if Mexico has the environmental availability that will allow T. erytreae invasion. We analyzed whether or not the distribution of Casimiroa edulis La Llave (Rutaceae) in the country could be a factor that enables the dispersal of T. eytreae. The environmental connectivity between five points of entry into the country (two ports and three airports) was explored to determine possible routes of dispersal of T. erytrae. The results showed that Mexico has wide availability for the invasion of the African citrus psyllid, which coincides with essential citrus areas of the country and with the distribution of C. edulis. Of the entry points studied, the Port of Veracruz showed nearby areas with environmental connectivity. Preventive monitoring measures for T. erytreae in Mexico should focus on Veracruz state because it has an entry point, ideal environmental availability, citrus areas, and specimens of C. edulis.

Do We Need New Crops for Arid Regions? A Review of Fruit Species Domestication in Israel

Climatic changes have created the imminent need for the development of new crops for arid regions. We started to domesticate and introduce wild and exotic fruit trees to our deserts in 1984. We tested different species in five eco zones in Israel, differing from each other in terms of maximum and minimum temperatures, type and degrees of salinities, water evaporation rates, rainfall, etc. We succeeded in cultivating pitaya species using hybrids from the Hylocereus and Selenicereus genera, and with a different species from the Cactaeae Cereus peruvianus, which we named Koubo. These two species are from the Cactaceae family, known for high water use efficiencies (WUE). We already have investors who started the semi-commercial production of Marula, Sclerocarya birrea sbsp. Caffra, and Argan—Argania spinosa. In spite of the fact that we developed good clones and knowledge of how to grow and ship White Sapote, Casimiroa edulis, and Indian jujube, Ziziphus mauritiana, we failed due to a lack of marketing research and development, which is essential for such a project. We have gene banks of some other new fruit crops waiting for investors to grow and bring them into the domestic and world markets.

Cytotoxic Prenyl and Geranyl Coumarins from the Stem Bark of Casimiroa edulis

Phytochemical investigation of the methanolic extract of the stem bark of Casimiroa edulis afforded four coumarins. Various spectroscopic experiments were used to characterize the isolated coumarins. The structures were identified as auraptene (K-1), suberosin (K-2), 5-geranyloxypsoralen (bergamottin) (K-3), and 8-geranyloxypsoralen (K-4), based on the chemical and spectral analysis. Among these compounds, suberosin (K-2) and 5-geranyloxypsoralen (bergamottin) (K-3) were isolated for the first time from this genus, and auraptene (K-1) was isolated from this plant for the first time. Cytotoxicity of pure compound K-4 and sub-fraction MD-3 was evaluated against HeLa and T47D cell lines and moderate activity was found with an IC50 value in the range 17.4 to 72.33 μg/mL.

Hydraulic traits vary as the result of tip-to-base conduit widening in vascular plants

Plant hydraulic traits are essential metrics for characterizing variation in plant function, but they vary markedly with plant size and position in a plant. We explore the potential effect of conduit widening on variation in hydraulic traits along the stem. We examined three species that differ in conduit diameter at the stem base for a given height (Moringa oleifera, Casimiroa edulis, and Pinus ayacahuite). We made anatomical and hydraulic measurements at different distances from the stem tip, constructed vulnerability curves, and examined the safety–efficiency trade-off with height-standardized data. Our results showed that segment-specific hydraulic resistance varied predictably along the stem, paralleling changes in mean conduit diameter and total number of conduits. The Huber value and leaf specific conductivity also varied depending on the sampling point. Vulnerability curves were markedly less noisy with height standardization, making the vulnerability–efficiency trade-off clearer. Because conduits widen predictably along the stem, taking height and distance from the tip into account provides a way of enhancing comparability and interpretation of hydraulic traits. Our results suggest the need for rethinking hydraulic sampling for comparing plant functional differences and strategies across individuals.