Bangladeshi medicinal plants (BMP) have a history of traditional use in treating chronic inflammatory diseases, but a BMP bark’s antioxidant and anti-inflammatory effects remain largely unexplored. This study assessed methanolic extracts’ antioxidant and anti-inflammatory properties from the bark of 15 medicinal plant species native to Bangladesh. The methanol extracts of BMP bark were evaluated for their total antioxidant activity and ability to counteract inflammation induced by lipopolysaccharide (LPS) in RAW 264.7 macrophages. Among the 15 bark extracts from BMP, Albizia odoratissima (A. odoratissima), Engelhardia spicata (E. spicata), and Shorea robusta (S. robusta) showed the highest total phenolic contents and total antioxidant capacity by effectively scavenging free radicals. In particular, these three bark extracts significantly reduced the mRNA expression of LPS-induced inflammatory cytokines and enzymes inducible by inflammation in macrophages. Also, the mRNA expression of NADPH oxidase 2 was significantly suppressed by the three bark extracts in LPS-induced RAW 264.7 macrophages. These results suggest that out of the 15 bark extracts obtained from medicinal plants in Bangladesh, the extracts from A. odoratissima, E. spicata, and S. robusta exhibit substantial total antioxidant capacity by efficiently scavenging free radicals and also inhibit LPS-induced inflammation in macrophages.

Aluminum (Al) is one of the major factors adversely affects crop growth and productivity in acidic soils. In this study, the effect of Al on plants in soil was investigated by comparing the protein expression profiles of alfalfa roots exposed to Al stress treatment. Two-week-old alfalfa seedlings were exposed to Al stress treatment at pH 4.0. Total protein was extracted from alfalfa root tissue and analyzed by two-dimensional gel electrophoresis combined with MALDI-TOF/TOF mass spectrometry. A total of 45 proteins differentially expressed in Al stress-treated alfalfa root tissues were identified, of which 28 were up-regulated and 17 were down-regulated. Of the differentially expressed proteins, 7 representative proteins were further confirmed for transcript accumulation by RT-PCR analysis. The identified proteins were involved in several functional categories including disease/defense (24%), energy (22%), protein destination (9%), metabolism (7%), transcription (5%), secondary metabolism (4%), and ambiguous classification (29%). The identification of key candidate genes induced by Al in alfalfa roots will be useful to elucidate the molecular mechanisms of Al stress tolerance in alfalfa plants.

Salicylic acid (SA) is an essential plant growth regulator that functions as a signaling molecule in plants. The purpose of this study was to clarify how the exogenous application of SA counteracts aluminum stress-induced growth and biomass yield reduction in alfalfa exposed to aluminum (Al) stress. Two-week-old alfalfa seedlings were exposed to a combination of AlCl3 (0 μM, 50 μM and 100 μM, respectively) and SA (0.1 mM) for 72 hours. We observed, Al stress-induced plant growth inhibition and forage yield reduction are Al stress-dependent manner. A significant reduction of plant height (42.0-52.9%), leaf relative water content (13.0-21.4%), root length (35.4-48.7%), shoot fresh weight (31.2-25.9%), root fresh weight (15.4-23.3%), shoot dry weight (12.7-22.2%), roots dry weight (47.3 -53.5%), were observed in alfalfa. In contrast, SA alleviated the Al-stress and enhanced growth and biomass yield in alfalfa. This study provides useful information concerning the role of SA that counteracts aluminum stress-induced growth and yield reduction in alfalfa.

Spodoptera litura Fabricius is the serious, polyphagous pest of various crops. Due to the high resistant to most of chemical pesticides, it is hard to control S. litura in the fields. We investigated the virulence of four entomopathogenic nematodes (EPNs) in each larval stage. All EPNs were more effective to younger larvae than older larvae. Mortality, larval penetration rate and reproduction rate were significantly higher in H. indica, S. carpocapsae and S. longicaudum than the H. bacteriophora. Three high effective EPNs induced complete mortality of first instar larvae within 48 h, but of fifth instar larvae within 72 h. These EPNs also highly effective to control S. litura in pot assay. Thus, H. indica, S. carpocapsae and S. longicaudum, can be used as efficient biological control agents of S. litura.

Geminiviruses are plant-infecting viruses with monopartite or bipartite single-stranded circular DNA genomes. They are known to be mediated by insects such as whiteflies, treehoppers, leafhoppers or aphids and can cause devastating plant diseases in a wide range of economically significant crops worldwide. In Korea, occurrence of geminiviruses were reported officially after the 2000s. Although Honeysuckle yellow vein virus (HYVV) and Sweet potato leaf curl virus (SPLCV) were identified from honeysuckle and sweet potato in 2004 and 2006 respectively, these viruses did not spread and cause much concern for geminiviruses. In 2008, Tomato yellow leaf curl virus (TYLCV) that has caused severe tomato production loss in many subtropical and tropical countries was first reported in tomato plants cultivated in Tongyeong. TYLCV rapidly spread through the country and has been continuously reported from tomato cultivating areas in Korea. In addition to TYLCV, Tobacco leaf curl virus and Sweet potato golden vein associated virus have occurred. In recent years, new geminiviruses including Papaya leaf curl Guangdong virus (PaLCGdV) and Euphorbia leaf curl virus (EuLCV) have been introduced. Newly emerging geminiviruses from tropical and subtropical countries are due to increased demand for various fruits and vegetables, and climate change. In addition, there are reports that some geminiviruses including TYLCV can be transmitted by infected seeds. Therefore it is important to study on epidemiology of virus introduction and spread among the countries and within country.