Developing Pheromone Traps and Lures for Maruca vitrata in Taiwan

The larvae of the legume pod borer, Maruca vitrata (Lepidoptera: Pyralidae), cause severe damage on economically important legume crops in the tropics. The female moth produces volatile components to attract males for mating. The so-called sex pheromones are species-specific multi-component blends and are used as lures in crop protection for pest monitoring. Their chemical identification and ratios is critical to design efficient lures. The following sex pheromone components for M. vitrata have been described: (E, E)-10,12-hexadecadienal (major compound), (E, E)-10,12-hexadecadienol and (E)-10-hexadecenal (minor components). The ratio of 100:5:5 of these components was the most attractive in trapping experiments in Benin, Africa. According to this ratio, a synthetic pheromone lure was developed for commercial use. But the commercially available blend was not attractive in field trapping experiments in other regions of sub-Saharan Africa and Southeast Asia. These findings lead to the conclusion that there is a possible polymorphism in the blend composition of the M. vitrata sex pheromone among populations from different geographical regions. In Taiwan, M. vitrata moths were never caught efficiently by the commercially available pheromone lures and traps. This paper reports trap and lure optimization experiments for effective trapping of Taiwanese M. vitrata moths in different leguminous crops.     

Genetic studies for seed size and grain yield traits in kabuli chickpea

Seed size, determined by 100-seed weight, is an important yield component and trade value trait in kabuli chickpea. In the present investigation, the small seeded kabuli genotype ICC 16644 was crossed with four genotypes (JGK 2, KAK 2, KRIPA and ICC 17109) and F₁, F₂ and F₃ populations were developed to study the gene action involved in seed size and other yield attributing traits. Scaling test and joint scaling test revealed the presence of epistasis for days to first flower, days to maturity, plant height, number of pods per plant, number of seeds per plant, number of seeds per pod, biological yield per plant, grain yield per plant and 100-seed weight. Additive, additive?×?additive and dominance?×?dominance effects were found to govern days to first flower. Days to maturity and plant height were under the control of both the main as well as interaction effects. Number of seeds per pod was predominantly under the control of additive and additive?×?additive effects. For grain yield per plant, additive and dominance?×?dominance effects were significant in the cross ICC 16644?×?KAK 2, whereas, additive?×?additive effects were important in the cross ICC 16644?×?JGK 2. Additive, dominance and epistatic effects influenced seed size. The study emphasized the existence of duplicate epistasis for most of the traits. To explore both additive and non-additive gene actions for phenological traits and yield traits, selection in later generations would be more effective.     

Seasonal deviation effects foliar endophyte assemblage and diversity in <Emphasis Type="Italic">Asparagus racemosus</Emphasis> and <Emphasis Type="Italic">Hemidesmus indicus</Emphasis>

Background

Fungal endophytes are the living symbionts which cause no apparent damage to the host tissue. The distribution pattern of these endophytes within a host plant is mediated by environmental factors. This study was carried out to explore the fungal endophyte community and their distribution pattern in Asparagus racemosus and Hemidesmus indicus growing in the study area.

Results

Foliar endophytes were isolated for 2 years from A. racemosus and H. indicus at four different seasons (June–August, September–November, December–February, March–May). A total of 5400 (675/season/year) leaf segments harbored 38 fungal species belonging to 17 genera, 12 miscellaneous mycelia sterile from 968 isolates and 13 had yeast like growth. In A. racemosus, Acremonium strictum and Phomopsis sp.1, were dominant with overall relative colonization densities (RCD) of 7.11% and 5.44% respectively, followed by Colletotrichum sp.3 and Colletotrichum sp.1 of 4.89% and 4.83% respectively. In H. indicus the dominant species was A. strictum having higher overall RCD of 5.06%, followed by Fusarium moniliforme and Colletotrichum sp.2 with RCD of 3.83% and 3%, respectively. Further the overall colonization and isolation rates were higher during the wet periods (September–November) in both A. racemosus (92.22% and 95.11%) and H. indicus (82% and 77.11%).

Conclusion

Study samples treated with 0.2% HgCl₂ and 75% EtOH for 30 s and 1 min, respectively, confirmed most favorable method of isolation of the endophytes. Owing to high mean isolation and colonization rates, September–November season proved to be the optimal season for endophyte isolation in both the study plants. Assessing the bioactive potential of these endophytes, may lead to the isolation of novel natural products and metabolites.

     

Development of conventional and real-time PCR protocols for specific and sensitive detection of Colletotrichum capsici in chilli (Capsicum annuum L.)

Anthracnose, caused by Colletotrichum capsici, is a major disease of chilli (Capsicum annuum L.) affecting both fruit and seed quality. The pathogen is both internally and externally seedborne. However, a rapid and sensitive method for detection of this pathogen in seeds is currently limited. In this study, a polymerase chain reaction (PCR) method based on sequence characterized amplified region (SCAR) marker was developed for specific and sensitive detection of C. capsici in chilli seeds and fruits. The developed SCAR primers were highly specific to C. capsici and resulted in the amplification of an expected 250-bp fragment from genomic DNA of all seven of the C. capsici isolates tested. No amplification occurred when the SCAR primers were tested with genomic DNA from three other fungal isolates and four other Colletotrichum species. The SCAR primers successfully amplified similar sized fragments from DNA derived from C. capsici-infected chilli fruits. The molecular detection sensitivity of C. capsici was 1 pg of purified C. capsici DNA template and 25 ng of DNA from C. capsici-infected chilli fruits. A real-time PCR assay was also developed using SYBR Green chemistry for detection of C. capsici in chilli fruits and seeds. The standard curve obtained showed a linear correlation between copy number of the cloned target DNA sequence of C. capsici and cycle threshold (Ct) values, with R² of 0.98. These PCR-based assays may be highly useful in detection of this important pathogen in chilli seeds and fruits in plant quarantine laboratories.     

Environmental risk factors for equine West Nile virus disease cases in Texas

West Nile Virus (WNV) was first detected in the Texas equine population during June 2002. Infection has since spread rapidly across the state and become endemic in the equine population. Environmental risk factors associated with equine WNV attack rates in Texas counties during the period 2002 to 2004 were investigated. Equine WNV attack rates were smoothed using an empirical Bayesian model, because of the variability among county equine populations (range 46−9,517). Risk factors investigated included hydrological features (lakes, rivers, swamps, canals and river basins), land cover (tree, mosaic, shrub, herbaceous, cultivated and artificial), elevation, climate (rainfall and temperature), and reports of WNV-positive mosquito and wild bird samples. Estimated county equine WNV attack rate was best described by the number of lakes, presence of broadleaf deciduous forest, presence of cultivated areas, location within the Brazos River watershed, WNV-positive mosquito status and average temperature. An understanding of environmental factors that increase equine WNV disease risk can be used to design and target disease control programs.     

Structural and functional analysis of KIT gene encoding receptor tyrosine kinase and its interaction with sunitinib and HDAC inhibitors: an in silico approach

KIT is a growth factor receptor, important for normal germ cell migration and development. The malfunction of KIT gene results in constitutive activation of the tyrosine kinase activity of c-KIT which is believed to be the major oncogenic event in stomach, small intestine mastocytosis, acute leukemias, melanomas and colon tumors. The genetics of these diseases could be better understood by knowing the functional relevance of their SNP variation. In this study, a computational analysis to detect the most deleterious nonsynonymous SNPs of KIT gene was performed and investigated its binding affinity to native and predicted mutant protein structure (D816V) with sunitinib and HDAC (Trichostatin A and Panobinostat) inhibitors was investigated. Out of 1,288 SNPs retrieved from dbSNP database against KIT gene, 11 non-synonymous SNPs were detected to be damaging and deleterious by SIFT, PolyPhen and I-Mutant2.0 servers. Further, we modeled the mutant protein based on the deleterious nsSNP (rs121913507) and showed that the mutation from Aspartic acid to Valine at 816 position exhibit greatest impact on stability. The RMSD values of mutant and native structures are found to be 0.40 and 1.9 A, respectively. Furthermore, the binding affinity of sunitinib and HDAC inhibitors were compared with native and mutant protein. In this regard, it was found that trichostatin A has a high binding efficacy towards the mutant protein with a binding energy of -35.274 kcal mol(-1), as compared to the native structure which has a binding energy of -25.996 kcal mol(-1). Also, the FastSNP tool suggested that 3 SNPs found to affect protein splicing site and splicing regulation. From present results, it was clear that the non-synonymous SNP rs121913507 (D816V) could be the most deleterious SNP for KIT gene and HDAC inhibitors can serve as a best drug for the mutant protein.     

Pericarp Fiber Separation from Corn Flour Using Sieving and Air Classification

In the dry‐grind process, starch in ground corn (flour) is converted to ethanol, and the remaining corn components (protein, fat, fiber, and ash) form a coproduct called distillers dried grains with solubles (DDGS). Fiber separation from corn flour would produce fiber as an additional coproduct that could be used as combustion fuel, cattle feed, and as feedstock for producing valuable products such as “cellulosic” ethanol, corn fiber gum, oligosaccharides, phytosterols, and polyols. Fiber is not fermented in the dry‐grind corn process. Its separation before fermentation would increase ethanol productivity in the fermenter. Recently, we showed that the elusieve process, a combination of sieving and elutriation (air flow), was effective in fiber separation from DDGS. In this study, we evaluated the elusieve process for separating pericarp fiber from corn flour. Corn flour remaining after fiber separation was termed “enhanced corn flour”. Of the total weight of corn flour, 3.8% was obtained as fiber and 96.2% was obtained as enhanced corn flour. Neutral detergent fiber (NDF) of corn flour, fiber, and enhanced corn flour (dry basis) were 9.0, 61.5, and 5.7%, respectively. Starch content of corn flour, fiber, and enhanced corn flour (dry basis) were 68.8, 23.5, and 71.3%, respectively. Final ethanol concentration from enhanced corn flour (14.12% v/v) was marginally higher than corn flour (13.72% v/v). No difference in ethanol yields from corn flour and enhanced corn flour was observed. The combination of sieving and air classification can be used to separate pericarp fiber from corn flour. The economics of fiber separation from corn flour using the elusieve process would be governed by the production of valuable products from fiber and the revenues generated from the valuable products.     

Hairy nightshade as a potential Potato leafroll virus (Luteoviridae: Polerovirus) inoculum source in Pacific Northwest potato ecosystems

Hairy nightshade, Solanum sarrachoides, is a solanaceous weed found abundantly in Pacific Northwest potato ecosystems. It serves as a reservoir for one of the important potato viruses, Potato leafroll virus (PLRV) (Luteoviridae: Polerovirus), and its most important vector, the green peach aphid, Myzus persicae (Homoptera: Aphididae). Laboratory research indicated an increased green peach aphid settling and performance on S. sarrachoides than on potato. It also revealed that green peach aphids transmitted PLRV more efficiently from S. sarrachoides to potato than from potato to potato. To test the efficiency of S. sarrachoides as an inoculum source in the field, a two season (2004 and 2005) trial was conducted at Kimberly, Idaho. Two inoculum sources, PLRV-infected potato and PLRV-infected S. sarrachoides, were compared in this trial. Green peach aphid density and temporal and spatial PLRV spread were monitored at weekly intervals. Higher densities of green peach aphids were observed on plots with S. sarrachoides and inoculum sources (PLRV-infected S. sarrachoides and potato) than on plots without S. sarrachoides and inoculum sources. PLRV infection in plots with PLRV-infected S. sarrachoides was similar to or slightly higher than in plots with PLRV-infected potato as an inoculum source. Temporal and spatial PLRV spread was similar in plots with either inoculum source. Thus, S. sarrachoides is as efficient as or a better PLRV inoculum source than potato.