Molecular diagnostics for detecting pyrethroid and organophosphate resistance mutations in the Q biotype of the whitefly Bemisia tabaci (Hemiptera: Aleyrodidae)

Pyrethroid and organophosphate resistance-associated mutations have been recently reported in the whitefly Bemisia tabaci (Gennadius), a major pest of protected and outdoor crops worldwide. Here, we developed simple PCR–agarose gel visualization based assays for reliably monitoring the L925I and T929V pyrethroid resistance mutations in the B. tabaci para-type voltage gated sodium channel and the iAChE F331W organophosphate resistance mutation in the acetylcholinesterase enzyme ace1.PCR-RFLP assays were developed for detecting the L925I and the F331W resistance mutations. A highly specific PASA was developed for detecting the T929V mutation. The molecular diagnostic tools were used to monitor the frequency of the resistance mutations in a large number of field caught Q biotype B. tabaci from Crete (Greece), where both organophosphates and pyrethroids are extensively used. The F331W mutation was fixed in all field individuals examined. The pyrethroid resistance mutations were detected in high frequencies: 0.38 and 0.54 for L925I and T929V, respectively. The simple diagnostics are accurate and robust, to be used alongside classical bioassays to prevent ineffective insecticide applications, and for early identification of the spreading of resistant Q biotype populations into new regions around the globe.     

Xanthone derivatives from the fermentation products of an endophytic fungus Phomopsis sp.

Three new xanthones, 1,5-dihydroxy-3-hydroxyethyl-6-methoxycarbonylxanthone (1), 1-hydroxy-5- methoxy-3-hydroxyethyl-6-methoxycarbonylxanthone (2), and 1-hydroxy-3-hydroxyethyl- 8-ethoxycarbonylxanthone (3), along with seven known xanthones (4–10) were isolated from the fermentation products of an endophytic fungus Phomopsis sp.. Their structures were elucidated by spectroscopic methods including extensive 1D- and 2D-NMR techniques. Compounds 1–10 were also tested for their cytotoxicity against five human tumor cell lines (NB4, A549, SHSY5Y, PC3, and MCF7) by MTT method using paclitaxel as positive control. Compounds 1 and 3 showed cytotoxicity against A549 cell lines with IC50 values of 3.6 and 2.5 μM, respectively. In addition, 1 was cytotoxic to MCF7 cells with IC50 value of 2.7 μM.     

Analysis of germination data from agricultural experiments

Expensive agricultural experiments deserve to be analyzed as efficiently as possible by extracting as much information as possible from the data while respecting the experimental design. We consider experiments where germination in response to time elapsed is used to characterize germination performance and vigour. We formulate statistical models in a biologically meaningful framework in such a way that the inherent data structure, which centers around repeatedly monitoring seeds over time, is duly incorporated in the statistical analysis. Consequently, estimation and model checking procedures are based on treating the data as event times, that is, to record the time it takes for germination (the event of interest) to occur. The key result is that the use of appropriate statistical models is important in order to get a better appreciation of the uncertainty that is present in germination experiments.     

Pestaloficiols Q–S from the plant endophytic fungus Pestalotiopsis fici

Two new isoprenylated chromone derivatives, pestaloficiols Q (1) and R (2), and one new benzofuran derivative, pestaloficiol S (3), along with three known metabolites, anofinic acid (4), siccayne (5), and pyrenophorol (6) were isolated from solid cultures of the plant endophytic fungus Pestalotiopsis fici. Their structures were elucidated primarily by NMR spectroscopy, and the absolute of the C-6 secondary alcohol in 1 was deduced on the basis of circular dichroism (CD) data. Compound 5 showed cytotoxic activity against the human cancer cell lines, HeLa and HT29, with IC₅₀ values of 48.2 and 33.9 μM, respectively.     

Bioactive carbazole alkaloids from Murraya koenigii (L.) Spreng

Four new carbazole alkaloids (1–4) and fourteen known carbazole alkaloids (5–18) were isolated from Murraya koenigii. Their structures were elucidated on the basis of extensive spectroscopic analysis. Compounds 4, 6, 16, and 17 (10 μM) had moderate hepatoprotective activities against d-galactosamine-induced HL-7702 cell damage. Compounds 11, 12 and 18 showed significant PTP1B inhibitory activity with IC₅₀ values of 1.773, 1.875 and 2.286 μM, respectively.     

Two novel dimeric indole alkaloids from the leaves and twigs of Psychotria henryi

Two novel dimeric indole alkaloids were isolated from the leaves and twigs of Psychotria henryi. Their structures were established by chemical and spectroscopic methods. Compound 1 was a novel dimeric tryptamine-related alkaloid that contained an unprecedented decacyclic ring system, and compound 2 featured a pyrido[3,4-b]indole moiety adjacent to a pyrrolidinoindole skeleton. The absolute configurations of compounds 1 and 2 were determined by calculation of electronic circular dichroism (ECD) using density functional theory (DFT).     

Moisture loss is the major cause of firmness change during postharvest storage of blueberry

Blueberry softening is known to be influenced by cell wall modifications accompanying ripening but these changes appear to be largely complete by the time of harvest. In this study postharvest storage conditions were controlled so only the extent of water loss varied between treatments. A linear relationship between weight loss and loss of firmness (as assessed by a non-destructive compression test) was demonstrated. This relationship did not hold at very low weight loss, where instead, firming of blueberries during storage was found. Magnetic resonance imaging of berries confirmed significant shrinkage and loss of water in berries which had high weight loss, compared with more subtle effects on sub-epidermal water content in berries with very low weight loss. Treatments which restrict blueberry water loss to below 8% are likely to be beneficial in retaining acceptable berry firmness for up to three weeks’ storage.     

Control of postharvest green mold of citrus fruit with yeasts,medicinal plants,and their combination

The use of bio-fungicides and a plant extracts to control postharvest disease was investigated as an alternative to chemical control. The combination of a promising plant extract and yeast were selected through in vitro and in vivo techniques. A combination of Candida utilis TISTR 5001 and Eugenia caryophyllata crude extract was the best combination to attain a reduction in disease incidence and disease severity of Penicillium digitatum on citrus fruit. Colonization was the lowest on fruit treated with the combination of E. caryophylata crude extract and C. utilis TISTR 5001, and survival of C. utilis TISTR 5001 was the highest. The combination of E. caryophylata crude extract and C. utilis TISTR 5001 significantly reduced the natural development of green mold of citrus fruit, and had no effect to fruit quality. The active compound of E. caryophylata was found to be eugenol, based on HPLC and NMR (¹H and ¹³C). Hence, the results indicate that a combination of plant extracts and yeasts posses antifungal activity that can be exploited as an ideal treatment for future plant disease management.     

Relationship between sensory and NIR spectroscopy in consumer preference of table grape (cv Italia)

A combination of near infrared spectroscopy (NIR) instrumental measurements and sensory analysis was investigated to predict solids soluble content (SSC, assessed as Brix) and to classify preference in table grape cv Italia. SSC was monitored in each berry of whole bunches in order to evaluate intra-bunch distribution and variability. NIR spectra were recorded in the spectral region 12,000–4000 cm⁻¹ (833–2500 nm) using a set of 682 berries. The Partial Least Square (PLS) model based on cross-validation provided acceptable value for the main statistical parameters (coefficient of determination of cross-validation, r²: 0.85; standard error of cross-validation, SECV: 1.08; residual predictive deviation, RPD: 2.6) and was confirmed by external validation performed with 115 independent berries (coefficient of determination of prediction, r_p²: 0.82; standard error of prediction, SEP: 0.83). For consumer testing, the selected PLS model was used to predict the Brix value in 400 berries and Discriminant Analysis (DA) was then carried out to classify berries in terms of preference by relating NIR data to consumer judgment. The three defined preference clusters of berries were fully classified obtaining 100% membership. In cross-validation the value decreased especially for class 1 (78.5%) and 3 (75%) whereas class 2 obtained comparable values (98.7%). According to our results, NIR technology appears to be a promising technique for predicting SSC and obtaining information with regard to consumer preference in ‘Italia’ table grape for application of efficient and low cost on-line instruments in the fruit industry.     

Light modulation of volatile organic compounds from petunia flowers and select fruits

Light intensity, duration, direction, and wavelength are informative to plants. The biochemical circuits that connect specific light wavelengths to expression of specific genes and the metabolic networks they govern have been well defined. However, little emphasis has been placed on how discrete wavelengths of light, alone or in combination, may be applied to manipulate postharvest qualities of high-value horticultural crops. Using narrow-bandwidth LED light we test the hypothesis that discrete light wavelengths can affect the accumulation of volatile compounds known to affect aroma or taste in select flower and fruit products. Volatile benzenoid/phenylpropanoid emission from petunia flowers could be altered with light application. Levels of a key floral volatile, 2-phenylethanol, increased with a red and far-red light treatment. Similar experiments demonstrated that fruit volatile profiles of tomato, strawberry, and blueberry can be manipulated with specific light treatments. These results suggest that compounds affecting sensory qualities of flowers and fruits can be modified by adjustment of ambient light conditions. These findings open new areas of inquiry about how the fragrance and flavor of flowers and fruits may be improved with simple changes in postharvest light conditions.