Although Polychronopolis and Lownsbery (1) found that Heterodera schachtii invaded the radicle, hypocotyl, and cotyledons of seedling sugarbeet, they observed no histological or cytological changes other than cellular death and disorganization. Ross (2) reported development of females and brown cysts accompanied by formation of giant cells and hypertrophy in leaves of white clover inoculated wi...

Phylogenetic analysis of new ribosomal DNA (rDNA) data for Heterodera mediterranea, H. hordecalis, H. carotae, and H. fici from Italy and H. ciceri from Syria, along with published data for other species, showed high bootstrap support for the following relationships: (((((H. carotae H. cruciferae) H. goettingiana) (((H. trifolii H. ciceri) H. mediterranea) ((H. avenae H. latipons) H. fici))) (C...

Genetic approaches are a powerful means to elucidate plant-pathogen interactions. An in vitro screening protocol was developed to identify Arabidopsis thaliana mutants with altered susceptibility to Heterodera schachtii, the sugar beet cyst nematode. In an initial screen of approximately 5,200 ethyl methanesulfonate-generated mutant plants, two stable mutations were identified. Both mutant line...

Trisomic and diploid hybrids of sugarbeet (Beta vulgaris L.) X wild beet (B. procumbens Chr. Sin.) inherited the gene for resistance to Heterodera schachtii Schm. from B. procumbens. The hybrids showed partial resistance to H. schachtii, manifested in failure of larvae to reach maturity. Although significantly greater numbers of female nematodes developed on plants inoculated with populations f...

In a taxonomic review of the species of the Heterodera "cacti group," H. thornei n. sp. is described and illustrated from Miner's lettuce in California. This new species is distinguishable especially by havpunctate egg shells and a larval stylet (27 mum) and tail (56 mum) longer than other related species. Heterodera weissi is redescribed, type specimens are designated, and new data added on th...

In a study of relationships among selected cyst-forming and noncyst-forming species of Heteroderoidea, combined sequences comprised of DNA from part of the conserved 18S ribosomal RNA gene (rDNA) plus the complete ITS rDNA segment were more similar to analyses based on the ITS data alone than to analyses based on the 18S data alone. One of the two noncyst-forming species, Ekphymatodera thomason...

We sequenced the entire coding region of the mitochondrial genome of Heterodera glycines. The sequence obtained comprised 14.9 kb, with PCR evidence indicating that the entire genome comprised a single, circular molecule of approximately 21-22 kb. The genome is the most T-rich nematode mitochondrial genome reported to date, with T representing over half of all nucleotides on the coding strand. ...

The effect of soil moisture on penetration, development, and reproduction of Heterodera cajani on pigeonpea (cv. ICPL 87) was investigated in growth chambers held at 20 and 25 C, and in a greenhouse where temperature fluctuated between 25 and 32 C. Averaged across temperatures, the percentage of juveniles that penetrated roots was 34.3, 31.8, 8.8, and 3.7% at 24, 32, 16, and 40% soil moisture l...

One hundred fifty rhizobacteria isolated from roots of Swiss chard grown in a soil suppressive to the sugar beet cyst nematode, Heterodera schachtii, were tested for their influence on the nematode's ability to hatch and infect roots. Two screening systems were used that focused on the ability of bacteria to inhibit either nematode hatching or root infection. Most of the bacterial strains reduc...