Anti-Markovnikov opening of trisubstituted epoxy alcohols: application in the synthesis of 2-methyl-1,3-diols

2-Methyl-1,3-diols are synthesized by regioselectively opening trisubstituted epoxides, prepared from 2-methylbut-2- en-1-ols at the more substituted carbon using Cp2TiCl- cyclohexa-1,4-diene

Editorial: impact of global climate change on the interaction between plants and plant-parasitic nematodes

Global climate change is an important environmental influence on plant ecosystems. Temperature, precipitation, duration and quality of sunlight, availability of nutrients, such as nitrogen, phosphorus and potassium, are determinants of plant growth that are likely to change due to global climate change effects. Climate change-induced high levels of atmospheric CO2 promote plant growth due to increased photosynthesis, at the cost of decreased evaporative cooling. In parallel, elevated CO2, temperature and altered precipitation levels strongly influence the biology of nematodes including plant and insect-parasitic nematodes. Although nematode development occur at a faster rate in warmer soil temperature, it is not yet clear about the precise implications of climate change effects on nematode biology as well as on plant-nematode interaction continuum

Tomato transgenic plants expressing hairpin construct of a nematode protease gene conferred enhanced resistance to root-knot nematodes

Root-knot nematodes (Meloidogyne incognita) cause substantial yield losses in vegetables worldwide, and are difficult to manage. Continuous withdrawal of environmentally-harmful nematicides from the global market warrants the need for novel nematode management strategies. Utility of host-delivered RNAi has been demonstrated in several plants (Arabidopsis, tobacco and soybean) that exhibited resistance against root-knot and cyst nematodes. Herein, a M. incognita-specific protease gene, cathepsin L cysteine proteinase (Mi-cpl-1), was targeted to generate tomato transgenic lines to evaluate the genetically modified nematode resistance. In vitro knockdown of Mi-cpl-1 gene led to the reduced attraction and penetration of M. incognita in tomato, suggesting the involvement of Mi-cpl-1 in nematode parasitism. Transgenic expression of the RNAi construct of Mi-cpl-1 gene resulted in 60-80% reduction in infection and multiplication of M. incognita in tomato. Evidence for in vitro and in vivo silencing of Mi-cpl-1 was confirmed by expression analysis using quantitative PCR. Our study demonstrates that Mi-cpl-1 plays crucial role during plant-nematode interaction and plant-mediated downregulation of this gene elicits detrimental effect on M. incognita development, reinforcing the potential of RNAi technology for management of phytonematodes in crop plants

The status of RNAi-based transgenic research in plant nematology

With the understanding of nematode-plant interactions at the molecular level, new avenues for engineering resistance have opened up, with RNA interference being one of them. Induction of RNAi by delivering double-stranded RNA (dsRNA) has been very successful in the model non-parasitic nematode, Caenorhabditis elegans, while in plant nematodes, dsRNA delivery has been accomplished by soaking nematodes with dsRNA solution mixed with synthetic neurostimulants. The success of in vitro RNAi of target genes has inspired the use of in planta delivery of dsRNA to feeding nematodes. The most convincing success of host-delivered RNAi has been achieved against root-knot nematodes. Plant-mediated RNAi has been shown to lead to the specific down-regulation of target genes in invading nematodes, which had a profound effect on nematode development. RNAi-based transgenics are advantageous as they do not produce any functional foreign proteins and target organisms in a sequence-specific manner. Although the development of RNAi-based transgenics against plant nematodes is still in the preliminary stage, they offer novel management strategy for the future

Synthetic studies on ophiobolins. Synthesis of 1β (H) -3,7,11β-trimethyl-CIS-bicyclo [6.3.0] undecan-4-one

In our synthetic studies towards ophiobolin F (1), we report here a stereospecific synthesis of 1β(H)-3,7α,llβ-trimethyl-cis bicyclo [6.3.0]undecan-4-one (2) with defined stereochemistry at each of the four contiguous asymmetric centres and particularly with A/B cis ring juncture as present in (1). It may be mentioned here that no synthetic studies towards developing the characteristic ring systems present in ophiobolins have been reported so far