Biological and Transcriptomic Characterization of Pre-Haustorial Resistance to Sunflower Broomrape ( W.) in Sunflowers ().

Infestations with sunflower broomrape ( Wallr.), an obligatory root parasite, constitute a major limitation to sunflower production in many regions around the world. Breeding for resistance is the most effective approach to reduce sunflower broomrape infestation, yet resistance mechanisms are often broken by new races of the pathogen.

Non-chemical Control of Root Parasitic Weeds with Biochar.

This study tested whether soil-applied biochar can impact the seed germination and attachment of root parasitic weeds. Three hypotheses were evaluated: (i) biochar adsorbs host-exuded signaling molecules; (ii) biochar activates plants' innate system-wide defenses against invasion by the parasite; and (iii) biochar has a systemic influence on the amount of seed germination stimulant produced or released by the host plant. Three types of experiments were performed: (I) pot trials with tomato () infested with .

The Influence of the Plant Growth Regulator Maleic Hydrazide on Egyptian Broomrape Early Developmental Stages and Its Control Efficacy in Tomato under Greenhouse and Field Conditions.

Broomrapes ( spp. and spp.) are holoparasitic plants that cause tremendous losses of agricultural crops worldwide.

Secondary Effects of Glyphosate Action in : Inhibition of Solute Transport from the Host Plant to the Parasite.

It is currently held that glyphosate efficiently controls the obligate holoparasite (Egyptian broomrape) by inhibiting its endogenous shikimate pathway, thereby causing a deficiency in aromatic amino acids (AAA). While there is no argument regarding the shikimate pathway being the primary site of the herbicide's action, the fact that the parasite receives a constant supply of nutrients, including proteins and amino acids, from the host does not fit with an AAA deficiency. This apparent contradiction implies that glyphosate mechanism of action in is probably more complex and does not end with the inhibition of the AAA biosynthetic pathway alone.

Maternal tissue is involved in stimulant reception by seeds of the parasitic plant Orobanche.

Background And Aims: A fundamental element in the evolution of obligate root-parasitic angiosperms is their ability to germinate only in response to chemical stimulation by roots, to ensure contact with a nearby nourishing host. The aim of this study was to explore inheritance of the unique germination control in this group of plants.

Methods: Analysis was made of the segregation of spontaneous (non-induced) germination that appeared in hybrid progenies derived from crosses between Orobanche cernua and O.

Seed ultrastructure and water absorption pathway of the root-parasitic plant Phelipanche aegyptiaca (Orobanchaceae).

Background And Aims: Obligate root parasitic plants of the Orobanchaceae do not germinate unless they chemically detect a host plant nearby. Members of this family, like Orobanche, Phelipanche and Striga, are noxious weeds that cause heavy damage to agriculture. In spite of their economic impact, only a few light microscopical studies of their minute seeds have been published, and there is no knowledge of their ultrastructure and of the role each tissue plays during the steps preceding germination.

Dehydrocostus lactone is exuded from sunflower roots and stimulates germination of the root parasite Orobanche cumana.

The germination of the obligate root parasites of the Orobanchaceae depends on the perception of chemical stimuli from host roots. Several compounds, collectively termed strigolactones, stimulate the germination of the various Orobanche species, but do not significantly elicit germination of Orobanche cumana, a specific parasite of sunflower. Phosphate starvation markedly decreased the stimulatory activity of sunflower root exudates toward O.

Is seed conditioning essential for Orobanche germination?

Background: Parasitic Orobanchaceae germinate only after receiving a chemical stimulus from roots of potential host plants. A preparatory phase of several days that follows seed imbibition, termed conditioning, is known to be required; thereafter the seeds can respond to germination stimulants. The aim of this study was to examine whether conditioning is essential for stimulant receptivity.

Changes in the activity of the alternative oxidase in Orobanche seeds during conditioning and their possible physiological function.

The appearance of the activity of the cyanide insensitive, alternative oxidase (AOX), pathway of oxygen uptake was followed in seeds of Orobanche aegyptiaca during conditioning. The pathway becomes operative during conditioning, up to day three as determined by inhibition of oxygen uptake of the seeds by propyl gallate. At the same time an increasing percentage of oxygen uptake is insensitive to cyanide and an increased oxygen uptake, responsive to propyl gallate, is induced by brief salicylic acid treatment of seeds.