New Analytical Approach to Quinolizidine Alkaloids and Their Assumed Biosynthesis Pathways in Lupin Seeds.

Alkaloids play an essential role in protecting plants against herbivores. Humans can also benefit from the pharmacological effects of these compounds. Plants produce an immense variety of structurally different alkaloids, including quinolizidine alkaloids, a group of bi-, tri-, and tetracyclic compounds produced by Lupinus species. Various lupin species produce different alkaloid profiles. To study the composition of quinolizidine alkaloids in lupin seeds, we collected 31 populations of two wild species native to Israel, L. pilosus and L. palaestinus, and analyzed their quinolizidine alkaloid contents. Our goal was to study the alkaloid profiles of these two wild species to better understand the challenges and prospective uses of wild lupins. We compared their profiles with those of other commercial and wild lupin species. To this end, a straightforward method for extracting alkaloids from seeds and determining the quinolizidine alkaloid profile by LC-MS/MS was developed and validated in-house. For the quantification of quinolizidine alkaloids, 15 analytical reference standards were used. We used GC-MS to verify and cross-reference the identity of certain alkaloids for which no analytical standards were available. The results enabled further exploration of quinolizidine alkaloid biosynthesis. We reviewed and re-analyzed the suggested quinolizidine alkaloid biosynthesis pathway, including the relationship between the amino acid precursor l-lysine and the different quinolizidine alkaloids occurring in seeds of lupin species. Revealing alkaloid compositions and highlighting some aspects of their formation pathway are important steps in evaluating the use of wild lupins as a novel legume crop.

Examination of genetic lines of Myrtus communis as potential sources of organic agricultural pest control agents.

Myrtus communis is a Mediterranean shrub cultivated in Israel for traditional, ceremonial use only, with more than 98 % of the crop biomass, equivalent to 26-27 tons per ha per annum, considered agricultural waste. Therefore, potentially profitable use for this excess is being highly sought. As Myrtus is also known for its unique terpene and terpenoid content, this work evaluated the impact of essential oil (EO) extracted from several M. communis cultivars on storage insects, nematodes, fungi, and pathogens. In addition, the allelopathic effect of M. communis litter on the germination success of wheat seeds was evaluated. The EO extracts demonstrated an insecticidal effect on several storage insects in fumigation experiment and a potentially inhibiting effect on wheat development in allelopathy experiments. No significant impact of M. communis EOs on the examined fungi, pathogens, and nematodes was recorded. Additional uses of the M. communis biomass suggest supplying additional income to the farmer through the circular agriculture approach. In addition, the use of this local crop can contribute to sustainable intensification by increasing farming efficiency, providing nature-based substitutes for chemical pesticides, and possibly, improving the future design of agriculture through the integration of Myrtus in monoculture crops.