Strigolactones are a class of bioactive natural metabolites produced by plant roots and released into the rhizosphere. They were discovered as signals indispensable for the induction of germination of seeds of root parasitic weeds, but since then, interestingly, many other biological, physiological and ecological roles have been described. This has suddenly provoked huge scientific interest in these compounds within different research fields. In this short perspective the attention is focused mainly on the ongoing and future research aimed at deciphering the biological roles of strigolactones that could positively affect, more or less directly, the management of parasitic weeds.
Promotive effects of four rice herbicides with different modes of action, pyrazosulfuron-ethyl, chlomethoxynil, pretilachlor and benzofenap, on the sprouting of lateral buds in Cyperus serotinus Rottb. tubers were examined.Although chlomethoxynil and benzofenap showed no effect, pyrazosulfuron-ethyl and pretilachlor increased the number of sprouting lateral buds. Pyrazosulfuron-ethyl was more effective than pretilachlor, and almost all of the lateral buds sprouted after treatment with this herbicide at 2g/10a. Furthermore, all of the other acetolactate synthase (ALS) inhibiting herbicides tested including bensulfuron-methyl, flazasulfuron and imazaquin also induced sprouting of lateral buds in C. serotinus tubers. The effect of bensulfuron-methyl was not eliminated by subsequently applied branched-chain amino acids, leucine, isoleucine or valine at 1 to 100ppm. These ALS inhibiting herbicides thus induce lateral bud sprouting and/or appear to eliminate apical dominance in C. serotinus tubers. Such an inductive effect on lateral bud sprouting may therefore be based on some interaction(s) between the herbicide and the plant hormones, presumably cytokinins, rather than on the depletion of branched-chain amino acids.
During the screening of metabolites of microorganisms for new insecticides, many piericidin-like substances were found in the mycelial extract of Streptomyces pactum. The isolation and physical properties of these piericidins are described.
