Diversity of the trifunctional histidine biosynthesis gene (his) in cereal Phaeosphaeria species.

Phaeosphaeria species are important causal agents of Stagonospora leaf blotch diseases in cereals. In this study, the nucleotide sequence and deduced polypeptide of the trifunctional histidine biosynthesis gene (his) are used to investigate the phylogenetic relationships and provide molecular identification among cereal Phaeosphaeria species. The full-length sequences of the his gene were obtained by PCR amplification and compared among cereal Phaeosphaeria species.

The Cercospora nicotianae gene encoding dual O-methyltransferase and FAD-dependent monooxygenase domains mediates cercosporin toxin biosynthesis.

Cercosporin, a photo-activated, non-host-selective phytotoxin produced by many species of the plant pathogenic fungus Cercospora, causes peroxidation of plant cell membranes by generating reactive oxygen species and is an important virulence determinant. Here we report a new gene, CTB3 that is involved in cercosporin biosynthesis in Cercospora nicotianae. CTB3 is adjacent to a previously identified CTB1 encoding a polyketide synthase which is also required for cercosporin production.

RNA polymerase II gene (RPB2) encoding the second largest protein subunit in Phaeosphaeria nodorum and P. avenaria.

A 5586 bp sequence (accession no. DQ278491), which includes the RNA polymerase II gene (RPB2) encoding the second largest protein subunit (RPB2), was obtained from the wheat biotype Phaeosphaeria nodorum (PN-w) by PCR amplification. The 3841 bp full length RPB2 gene contains two exons and a 52 bp intron, and encodes a complete 1262 amino acid protein.

Sequence diversity of beta-tubulin (tubA) gene in Phaeosphaeria nodorum and P. avenaria.

Full-length coding sequences of the beta-tubulin gene (tubA) were PCR-amplified and sequenced from 42 Phaeosphaeria isolates, including 16 P. nodorum and 23 P. avenaria species from cereals, two Polish isolates from rye (Secale cereale L.

The CTB1 gene encoding a fungal polyketide synthase is required for cercosporin biosynthesis and fungal virulence of Cercospora nicotianae.

Cercosporin is a light-activated, non-host-selective toxin produced by many Cercospora fungal species. In this study, a polyketide synthase gene (CTB1) was functionally identified and molecularly characterized to play a key role in cercosporin biosynthesis by Cercospora nicotianae. We also provide conclusive evidence to confirm the crucial role of cercosporin in fungal pathogenesis.

Induction of phytohormones and differential gene expression in citrus flowers infected by the fungus Colletotrichum acutatum.

Colletotrichum acutatum infects citrus petals and induces premature fruit drop and the formation of persistent calyces. The accumulation of hormones and other growth regulators, and differential gene expression in affected flowers and young fruit, was examined following fungal infection. Ethylene evolution increased threefold and indole-3-acetic acid (IAA) accumulation was as much as 140 times.

Indole derivatives produced by the fungus Colletotrichum acutatum causing lime anthracnose and postbloom fruit drop of citrus.

Postbloom fruit drop (PFD) of citrus and Key lime anthracnose (KLA) are caused by Colletotrichum acutatum. Both fungal isolates can infect flower petals, induce young fruit abscission and result in severe yield loss on many citrus cultivars. Previous studies revealed that infection of citrus flowers by C.

QTL mapping of partial resistance in winter wheat to Stagonospora nodorum blotch.

Stagonospora nodorum blotch is an important foliar and glume disease in cereals. Inheritance of resistance in wheat appears to be quantitative. To date, breeding of partially resistant cultivars has been the only effective way to combat this pathogen.

Sequence diversity of mating-type genes in Phaeosphaeria avenaria.

Phaeosphaeria avenaria, one of the causal agents of stagonospora leaf blotch diseases in cereals, is composed of two subspecies, P. avenaria f. sp.

TAXONOMY AND IDENTIFICATION OF SEPTORIA AND STAGONOSPORA SPECIES ON SMALL-GRAIN CEREALS.

Numerous significant changes have been made in the taxonomy of both the anamorphs and teleomorphs of the Septoria group of leaf spot pathogens on small grain cereals during the past 30 years. The pathogens fall into two related but distinct groups, with anamorphic genera now placed in Septoria and Stagonospora of the Sphaeropsidales. Each of these genera has distinct teleomorphs in the Loculoascomycetes in Mycosphaerella and Phaeosphaeria.