Fitness of Cuscuta salina (Convolvulaceae) parasitizing Beta vulgaris (Chenopodiaceae) grown under different salinity regimes.

The distribution of saltmarsh dodder (Cuscuta salina) worldwide is restricted to areas of high salinity, where it parasitizes a variety of salt-tolerant plants. Because dodders do not maintain root connections to the soil, this pattern of parasitization may be related to the effects of salt stress on the host that increase the ability of attached dodders to more easily transfer host contents. This study explored whether a saline host environment is required for successful infection and whether stem contents of potential hosts become more concentrated in response to salinity.

Costs of resistance.

Studies of the reduction of fitness in plants expressing resistance characteristics have always been popular. New techniques for manipulating defense expression have recently resulted in a greater understanding of the mechanisms through which different types of resistance strategies produce costs, especially those costs associated with inducible defenses.

Exploring the Physiological Basis of Costs of Herbicide Resistance in Arabidopsis thaliana.

For some resistance traits identified in crop and weed species, plant physiologists have detailed knowledge of the mechanism of gene action that distinguishes the physiology of resistant and susceptible genotypes. Such information could be useful to those evolutionary biologists interested in coupling the genetics and physiology of resistance mutations with data on the relative fitness of resistant and susceptible genotypes. In previous work, we have shown that the lifetime seed production of chlorsulfuron-resistant Arabidopsis thaliana was substantially lower than that of susceptible plants, and here we explore potential physiological reasons for the fitness reduction.

Fitness consequences of genetically engineered herbicide and antibiotic resistance in Arabidopsis thaliana.

Researchers have often invoked the concept of metabolic drain to explain the lower growth rates of bacteria containing plasmids that confer antibiotic resistance. This idea posits that the energetic input needed to produce detoxifying enzymes diverts resources from clonal reproduction. In this paper we examine whether the concept of metabolic drain can be applied successfully to plants that differ from bacteria in several key aspects including their relative genome size and reproductive rate.