Fifty-two alfalfa (Medicago sativa L.) clones, randomly selected from the cultivar Baker and the experimental line MNGRN-4, were evaluated for resistance (based on nematode reproduction) to Pratylenchus penetrans in growth chamber tests (25 C). Twenty-five clones, representing the range of nematodes and eggs per plant, were selected and retested. Four moderately resistant and two susceptible al...

The most represented group of resistance genes are those of the nucleotide binding site-leucine-rich repeat (NBS-LRR) class. These genes are very numerous in the plant genome, and they often occur in clusters at specific loci following gene duplication and amplification events. To date, hundreds of resistance genes and relatively few quantitative trait loci for plant resistance to pathogens have ...

Virus diseases are significant threats to modern agriculture and their control remains a challenge to the management of cultivation. The main virus resistance strategies are based on either natural resistance or engineered virus-resistant plants. Recent progress in understanding the molecular mechanisms underlying the roles of resistance genes has promoted the development of new anti-virus stra...

Animal SGT1 is a component of Skp1-Cullin-F-box protein (SCF) ubiquitin ligases that target regulatory proteins for degradation. Mutations in one (SGT1b) of two highly homologous Arabidopsis SGT1 genes disable early plant defenses conferred by multiple resistance (R) genes. Loss of SGT1b function in resistance is not compensated for by SGT1a. R genes differ in their requirements for SGT1b and a...

The plant genes required for the growth and reproduction of plant pathogens are largely unknown. In an effort to identify these genes, we isolated Arabidopsis mutants that do not support the normal growth of the powdery mildew pathogen Erysiphe cichoracearum. Here, we report on the cloning and characterization of one of these genes, PMR6. PMR6 encodes a pectate lyase-like protein with a novel C...

The Plant Resistance Genes database (PRGdb; http://prgdb.org) has been redesigned with a new user interface, new sections, new tools and new data for genetic improvement, allowing easy access not only to the plant science research community but also to breeders who want to improve plant disease resistance. The home page offers an overview of easy-to-read search boxes that streamline data querie...

Commercial sweet orange cultivars lack resistance to Huanglongbing (HLB), a serious phloem limited bacterial disease that is usually fatal. In order to develop sustained disease resistance to HLB, transgenic sweet orange cultivars 'Hamlin' and 'Valencia' expressing an Arabidopsis thaliana NPR1 gene under the control of a constitutive CaMV 35S promoter or a phloem specific Arabidopsis SUC2 (AtSU...

The plant genes required for the growth and reproduction of plant pathogens are largely unknown. In an effort to identify these genes, we isolated Arabidopsis mutants that do not support the normal growth of the powdery mildew pathogen Erysiphe cichoracearum . Here, we report on the cloning and characterization of one of these genes, PMR6 . PMR6 encodes a pectate lyase–like protein with a novel...

Late blight (LB) caused by the oomycete Phytophthora infestans continues to thwart global tomato production, while only few resistant cultivars have been introduced locally. In order to gain from the released tomato germplasm with LB resistance, we compared the 5-year field performance of LB resistance in several tomato cultigens, with the results of controlled conditions testing (i.e., detache...

It is well known that plant damage by leaf-chewing herbivores can induce resistance in neighbouring plants. It is unknown whether such communication occurs in response to sap-feeding herbivores, whether communication is specific to herbivore identity, and the chemical basis of communication, including specificity. We carried out glasshouse experiments using the California-native shrub Baccharis...