The Strategy of Parasitic Weeds Destructive to Agricultural Production

The most destructive and intractable problems to agricultural production, which is the beautiful flower-Broomrape. It's holoparasitic plants that subsist on the roots of a variety of agricultural crops, causing heavy damage, reducing the yield and its quality in semiarid regions of the world. Parasitic weeds are difficult to control or at present uncontrollable by conventional means due to their life style. The parasites are closely associated to the host root, concealed underground and undiagnosed until they irreversible damage the crop. Although, the simplest and most effective approach to parasitic weeds control – host resistance remains an unrealized goal for agriculture, a wide variety of parasitic weed control (chemical, biological, cultural and resistant crops) has been tried. But some agriculture ground cover products can be used.

In fact, the best control method, which was applied several years ago, was by fumigation with methyl bromide and safety fence net. This method, however, is expensive, laborious, and it is now phased out because it is extremely hazardous to the environment. The discovery of RNA silencing is one of the most important biotechnological findings of the last decade. In several organisms introduction of double-stranded (dsRNA) has proved to be a powerful tool to suppress gene expression through a process known as RNA interference (RNAi) in animals and post-transcriptional gene silencing (PTGS) in plants.

In the current study, we suggest an improved strategy for the control of parasitic weeds based on trans-specific gene silencing of three parasite genes at once. To express dsRNA containing selected sequences of three Phelipanche aegyptiaca genes PaACS, PaM6PR and PaPrx1 (pma), we used a hairpin construct (pBINPLUS35:pma) for stable expression in transgenic tomato Solanum lycopersicum (Mill.) plants. Concomitant with the suppression of the target genes, there were significant decreases in the number and weight of the parasite tubercles that grew on the silenced-host plants.

Furthermore, plant support net for plants expressing the parasite target genes showed enhanced resistance to P. aegyptiaca as evidenced by abnormal parasite development and higher parasite mortality after attachment, as compared to non-transformed plants. Alternative biotechnological approaches using siRNA could be ideal for parasitic weed control.