No abstract

The yield response of widely grown cultivars and landraces of Syrian wheat challenged with common root rot (CRR: Cochliobolus sativus) was measured by comparing plots with and without artifi cial inoculation under experimental conditions in two consecutive seasons. The results showed that response to CRR diff ered depending on the susceptibility levels of the wheat cultivars, and that the disease signifi cantly (P<0.05) reduced grain yield, number of tillers and kernel weight. The diseased plants had fewer tillers which consequently reduced grain yield per plant. Yield losses of Triticum durum cultivars were higher than those of Triticum aestivum. In addition, the T. durum landrace Horani exhibited the best level of resistance to the disease, which indicates that this landrace might be a candidate donor for resistance in future breeding programmes. As CRR can dramatically reduce wheat grain yields under favorable conditions, management practices that reduce disease severity are highly recommended.

SummaryThe eff ect of Pseudomonas putida BTP1, Bacillus subtilis Bs2500, Bs2504, and Bs2508 strains on the incidence (I) and severity (S) of barley leaf stripe disease caused by Pyrenophora graminea was evaluated under fi eld conditions. Three barley cultivars varying in resistance level were used. The resistance achieved in our study was long-lasting. P. putida BTP1 and Bs2508 were in general the most eff ective strains in reducing signifi cantly both I and S of barley leaf stripe disease vis-a-vis three cultivars in two growing seasons 2013/2014. The disease was reduced up to 66% in Arabi Abiad treated with P. putida BTP1. The susceptible landrace cultivar Arabi Abiad exhibited a signifi cant induction of resistance by Bs2508 and BTP1. However, the resistant cultivar Banteng did not exhibit signifi cant further increase in resistance by these bacterial strains. The grain yield of bacterized plants artifi cially inoculated with P. graminea was not aff ected, except that of the cultivar Arabi Abiad treated with Bs2508 and Bs2504. Triggering of resistance by treating seeds with the bacterial strains would be of great value in agriculture, especially in case of barley infection by P. graminea at an early stage of plant development.

No abstract

Leaf scald caused by the infection of Rhynchosporium secalis, is a worldwide crop disease resulting in significant loss of barley yield. In this study, a systematic sequencing of expressed sequence tags (ESTs) was chosen to obtain a global picture of the assembly of genes involved in pathogenesis. To identify a large number of plant ESTs, which are induced at different time points, an amplified fragment length polymorphism (AFLP) display of complementary DNA (cDNA) was utilized. Transcriptional changes of 140 ESTs were observed, of which 19 have no previously described function. Functional annotation of the transcripts revealed a variety of infection-induced host genes encoding classical pathogenesis-related (PR) or genes that play a role in the signal transduction pathway. The expression analyses by a semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) revealed that Rar1 and Rpg4 are defense inducible genes, and were consistent with the cDNA-AFLP data in their expression patterns. Hence, the here presented transcriptomic approach provides novel global catalogue of genes not currently represented in the EST databases.