Browsing by Author "Hoisington, David A."

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Isolation and sequence analysis of DREB2A homologues in three cereal and two legume species
(Elsevier B.V., 2009) Nayak, Spurthi N.; Balaji, Jayashree; Upadhyaya, Hari D.; Hash, C. Tom; Kavi Kishor, P.B.; Chattopadhyay, Debasis; Rodriquez, Lina Marıa; Blair, Matthew W.; Baum, Michael; McNally, Kenneth; This, Dominique; Hoisington, David A.; Varshney, Rajeev K.
The transcription factor, DREB2A, is one of the promising candidate genes involved in dehydration tolerance in crop plants. In order to isolate DREB2A homologues across cereals (rice, barley and sorghum) and legumes (common bean and chickpea), specific or degenerate primers were used. Gene/phylogenetic trees were constructed using a non-redundant set of 19 DREB1A and 27 DREB2A amino acid sequences and were combined with taxonomic/species tree to prepare reconciled phylogenetic trees. In total, 86 degenerate primers were designed for different clades and 295 degenerate primer combinations were used to amplify DREB homologues in targeted crop species. Successful amplification of DREB2A was obtained in case of sorghum. In parallel, gene-specific primers were used to amplify DREB2A homologues in rice, barley, common bean and chickpea. Seven to eight diverse genotypes from targeted species were used for sequence analysis at DREB2A locus identified/isolated. A maximum of eight SNPs were found in the common bean DREB2A, indicating two distinct haplotypes, three SNPs with five haplotypes were observed in barley whereas a single SNP was observed in rice, sorghum and chickpea. Parsimony based phylogenetic tree revealed distinct clustering of cereals and legumes. Furthermore, alignment of corresponding amino acid sequences showed conservation of AP2 domain across the targeted species.
Molecular genetics and breeding of grain legume crops for the semi-arid tropics
(Springer, 2007) Varshney, Rajeev K.; Hoisington, David A.; Upadhyaya, Hari D.; Gaur, Pooran M.; Nigam, Shyam N.; Saxena, Kulbhushan; Vadez, Vincent; Sethy, Niroj K.; Bhatia, Sabhyata; Aruna, Rupakula; Gowda, M. V. Channabyre; Singh, Nagendra K.
Grain legumes are important crops for providing key components in the diets of resource-poor people of the semi-arid tropic (SAT) regions of the world. Although there are several grain legume crops grown in SAT, the present chapter deals with three important legumes i.e. groundnut or peanut (Arachis hypogaea), chickpea (Cicer arietinum) and pigeonpea (Cajanus cajan). Production of these legume crops are challenged by serious abiotic stresses e.g. drought, salinity as well as several fungal, viral and nematode diseases. To tackle these constraints through molecular breeding, some efforts have been initiated to develop genomic resources e.g. molecular markers, molecular genetic maps, expressed sequence tags (ESTs), macro-/micro- arrays, bacterial artificial chromosomes (BACs), etc. These genomic resources together with recently developed genetic and genomics strategies e.g. functional molecular markers, linkage-disequilibrium (LD) based association mapping, functional and comparative genomics offer the possibility of accelerating molecular breeding for abiotic and biotic stress tolerances in the legume crops. However, low level of polymorphism present in the cultivated genepools of these legume crops, imprecise phenotyping of the germplasm and the higher costs of development and application of genomic tools are critical factors in utilizing genomics in breeding of these legume crops.