Molecular characterization of the genomic region harboring the BYDV-resistance geneBdv2 in wheat

Genome Analysis of Thinopyrum intermedium and Its Potential Progenitor Species Using Oligo-FISH

The genome composition of intermediate wheatgrass (IWG) is complex and continues to be a subject of investigation. In this study, molecular cytogenetics were used to investigate the karyotype composition of Th. intermedium and its relative diploid species. St2-80 developed from Pseudowroegneria strigose and pDb12H developed from Dasypyrum breviaristatum were used as probes in fluorescence in situ hybridization (FISH) to classify the chromosomes of Th. intermedium into three groups, expressed as JvsJvsJrJrStSt. A combined multiplex oligonucleotide probe, including pSc119.2-1, (GAA)10, AFA-3, AFA-4, pAs1-1, Pas1-3, pAs1-4, and pAs1-6, was used to establish the FISH karyotype of ten accessions of Th. intermedium. Variability among and within the studied accessions of intermediate wheatgrass was observed in their FISH patterns. Results of this study led to the conclusions that Jvs had largely been contributed from Da. breviaristatum, but not the present-day Da. villosum; IWG had only one J genome, Jr, which was related to either Th. elongatum or Th. bessarabicum; and St was contributed from the genus Pseudoroegneria by hybridization with Th. junceiforme or Th. sartorii.

Diagnosis and control of cereal viruses in the Middle East

Middle Eastern countries are major consumers of small grain cereals. Egypt is the biggest bread wheat producer with 7.4 million tons (MT) in 2007, but at the same time, it had to import 5.9 MT. Jordan and Israel import almost all the grains they consume. Viruses are the major pathogens that impair grain production in the Middle East, infecting in some years more than 80% of the crop. They are transmitted in nonpersistent, semipersistent, and persistent manners by insects (aphids, leafhoppers, and mites), and through soil and seeds. Hence, cereal viruses have to be controlled, not only in the field but also through the collaborative efforts of the plant quarantine services inland and at the borders, involving all the Middle Eastern countries. Diagnosis of cereal viruses may include symptom observation, immunological technologies such as ELISA using polyclonal and monoclonal antibodies raised against virus coat protein expressed in bacteria, and molecular techniques such as PCR, microarrays, and deep sequencing. In this chapter, we explore the different diagnoses, typing, and detection techniques of cereal viruses available to the Middle Eastern countries. We highlight the plant quarantine service and the prevention methods. Finally, we review the breeding efforts for virus resistance, based on conventional selection and genetic engineering.