The demand for food is increasing with growing world population, while agricultural land is becoming scarcer, therefore it is important to increase the yield of crop plants on the existing land. Primary reason for crop yield losses are pests, such as insects, viruses and bacteria, however parasitic plants are also becoming an increasing problem. Parasitic plants form a specific structure called haustorium, through which they draw nutrients and water from their hosts, impacting host growth and productivity. Apart from host tolerance, there is no general method for controlling parasitic plants, but understanding the physiology, host interactions and evolution of parasitic plants is crucial for its development. The biggest problem with parasitic plants control is the long dormancy of the seeds, because they can survive in the soil for up to a few decades. In the presence of a germination stimulant, a certain compound produced by host plant, they germinate, and when suitable host is detected through a haustorium inducing factor (HIF), they form a haustorium. Nutrients and water are transferred through the haustorium, but in some cases genetic material, RNA or DNA, is actively transferred as well. Over the course of evolution, certain genes have been incorporated in the genomes of parasitic plants, thereby increasing their viability or improving parasitic traits. Most of these so-called horizontally transferred genes (HGT genes) are silent, but some of them have been recognized as highly expressed in the parasite plants, participating in key functions like metabolism, cell respiration, mitochondrial translation and conversion of proteins. Certain HGT genes are also associated with suppression of the host defence mechanisms.
|
