Hussein M. Migdadi

Molecular Diversity Assessment Using Sequence Related Amplified Polymorphism (SRAP) Markers in Vicia faba L.

Sequence-related amplified polymorphism (SRAP) markers were used to assess the genetic diversity and relationship among 58 faba bean (Vicia faba L.) genotypes. Fourteen SRAP primer combinations amplified a total of 1036 differently sized well-resolved peaks (fragments), of which all were polymorphic with a 0.96 PIC value and discriminated all of the 58 faba bean genotypes. An average pairwise similarity of 21% was revealed among the genotypes ranging from 2% to 65%. At a similarity of 28%, UPGMA clustered the genotypes into three main groups comprising 78% of the genotypes. The local landraces and most of the Egyptian genotypes in addition to the Sudan genotypes were grouped in the first main cluster. The advanced breeding lines were scattered in the second and third main clusters with breeding lines from the ICARDA and genotypes introduced from Egypt. At a similarity of 47%, all the genotypes formed separated clusters with the exceptions of Hassawi 1 and Hassawi 2. Group analysis of the genotypes according to their geographic origin and type showed that the landraces were grouped according to their origin, while others were grouped according to their seed type. To our knowledge, this is the first application of SRAP markers for the assessment of genetic diversity in faba bean. Such information will be useful to determine optimal breeding strategies to allow continued progress in faba bean breeding.

Faba bean genomics: Current status and future prospects

Faba bean represents a crucial source of protein for food, especially for Mediterranean countries, and local demand for faba bean grains is increasing. The crop is also gaining increased attention as an elite candidate for conservation agriculture. However, the complexity of the faba genome has made progress in breeding programs and molecular studies relatively slow compared with other legume crops. Recent advances in plant genomics have made it feasible to understand complex genomes such as faba bean. With the increase of faba bean consumption in the Middle East region, there is an urgent need to develop elite faba genotypes suitable for arid and semi arid environments, with high yield potential and acceptable nutritional quality. This article highlights the recent advances in legume and faba genomics and its potential to contribute to the above mentioned goal. Emphasis is given on prospects on faba improvements strategies from the Middle East point of view.

Mitochondrial DNA support for genetic reserves of Apis mellifera syriaca in Jordan.

Summary We analyzed mitochondrial DNA variation in honey bee colonies in Jordan using DraI restriction profiles of the COI-COII intergenic region. Seven different haplotypes were observed, three of which belonged to the C mitochondrial lineage. Samples displaying haplotypes of the C lineage were concentrated in the north of the country where frequent importations of European bees have occurred. We conclude that the C mitochondrial haplotypes found in the study reflect past or recent importations of non-native honey bees. No C haplotypes were detected in areas that have been identified as possible source populations for the conservation of original A. m. syriaca in the south of the sampling region, thus confirming the existence of comparatively pure genetic resources of this subspecies in Jordan.

Morphological and molecular genetic variability analyses of Saudi lucerne (Medicago sativa L.) landraces

Abstract. Collection and characterisation of genetic resources are required for the development of new cultivars. We analysed genetic diversity among 18 non-dormant lucerne (alfalfa, Medicago sativa L.) accessions including ten local ecotypes and eight introduced accessions at morphological and molecular levels using sequence-related amplified polymorphism (SRAP) primers. Standardised canonical discrimination functions for the investigated morphological traits showed that the first function (explaining 75% of total variability among accessions) was strongly influenced by leaflet shape, stipule shape, and the peduncle : petiole length ratio. The 16 SRAP primer pair combinations generated 677 differently sized SRAP fragments (peaks), of which 665 (98.3%) were polymorphic across all 18 accessions. We detected high levels of polymorphism (average polymorphic information content value = 0.96, average of 42.3 polymorphic fragments per primer pair). Based on morphological and SRAP data, local accessions tended to group together in the same cluster or formed individual clusters. Clusters of local accessions at high similarity sometimes correlated with their collection site (Qasemi-2 and Qasemi-3) on molecular analysis. Results of cluster analysis based on SRAP showed no significant correlation with morphological characters based on the Mantel test (r = 0.04).This inconsistent clustering of accessions could be due to the allelic variation (presumably) in a small number of genes (24 traits) contributing to morphological characterisation, while the 677 SRAP fragments (loci) are assumed to be relatively widely distributed across the genome. The wide geographical distribution of lucerne populations across different environments may provide good genetic resources for breeding purposes. SRAP analysis was effective to study genetic variability of non-dormant lucerne. This information will be helpful in assessing selections for lucerne breeding programs to develop new cultivars adapted to harsh environmental conditions.

Phenological, Nutritional and Molecular Diversity Assessment among 35 Introduced Lentil (Lens culinaris Medik.) Genotypes Grown in Saudi Arabia

Morphological, nutritional and molecular analyses were carried out to assess genetic diversity among 35 introduced lentil genotypes (Lens culinaris Medik.). The genotypes exhibited significant differences for their field parameters and some of them showed noticeable superiority. The nutritional and proximate analysis showed that some genotypes were excellent sources of proteins, essential amino acids, minerals, anti-oxidants, total phenolic contents (TPC) and total flavonoid contents (TFC) and hence, highlights lentil nutritional and medicinal potential. Sequence-related amplified polymorphism (SRAP) and amplified fragments length polymorphism (AFLP) markers were used to estimate the genetic variability at the molecular level. The existence of a considerable amount of genetic diversity among the tested lentil genotypes was also proven at the molecular level. A total of 2894 polymorphic SRAP and 1625 AFLP loci were successfully amplified using six SRAP and four AFLP primer pair combinations. Polymorphism information content (PIC) values for SRAP and AFLP markers were higher than 0.8, indicating the power and higher resolution of those marker systems in detecting molecular diversity. UPGMA (unweighted pair group method with arithmetic average) cluster analysis based on molecular data revealed large number of sub clusters among genotypes, indicating high diversity levels. The data presented here showed that FLIP2009-64L and FLIP2009-69L could be used as a significant source of yield, total protein, essential amino acids, and antioxidant properties. The results suggest potential lentil cultivation in the central region of Saudi Arabia for its nutritional and medicinal properties, as well as sustainable soil fertility crop.

Effects, tolerance mechanisms and management of salt stress in grain legumes

Salt stress is an ever-present threat to crop yields, especially in countries with irrigated agriculture. Efforts to improve salt tolerance in crop plants are vital for sustainable crop production on marginal lands to ensure future food supplies. Grain legumes are a fascinating group of plants due to their high grain protein contents and ability to fix biological nitrogen. However, the accumulation of excessive salts in soil and the use of saline groundwater are threatening legume production worldwide. Salt stress disturbs photosynthesis and hormonal regulation and causes nutritional imbalance, specific ion toxicity and osmotic effects in legumes to reduce grain yield and quality. Understanding the responses of grain legumes to salt stress and the associated tolerance mechanisms, as well as assessing management options, may help in the development of strategies to improve the performance of grain legumes under salt stress. In this manuscript, we discuss the effects, tolerance mechanisms and management of salt stress in grain legumes. The principal inferences of the review are: (i) salt stress reduces seed germination (by up to more than 50%) either by inhibiting water uptake and/or the toxic effect of ions in the embryo, (ii) salt stress reduces growth (by more than 70%), mineral uptake, and yield (by 12-100%) due to ion toxicity and reduced photosynthesis, (iii) apoplastic acidification is a good indicator of salt stress tolerance, (iv) tolerance to salt stress in grain legumes may develop through excretion and/or compartmentalization of toxic ions, increased antioxidant capacity, accumulation of compatible osmolytes, and/or hormonal regulation, (v) seed priming and nutrient management may improve salt tolerance in grain legumes, (vi) plant growth promoting rhizobacteria and arbuscular mycorrhizal fungi may help to improve salt tolerance due to better plant nutrient availability, and (vii) the integration of screening, innovative breeding, and the development of transgenics and crop management strategies may enhance salt tolerance and yield in grain legumes on salt-affected soils.

Inter-simple sequence repeat (ISSR)-based diversity assessment among faba bean genotypes

Thirty-four faba bean (Vicia faba L.) including local and exotic materials were subjected to molecular diversity assessment using 12 inter-simple sequence repeat primers. The molecular data showed unambiguous and qualitative (present or absent) fragments that gave repeatable patterns were considered for the analysis. The 12 selected primers produced a total of 71 fragments (loci), all of which were polymorphic using the 34 collected faba genotypes. The results of clustering Nei’s genetic distance using the unweighted pair group method with arithmetic average algorithm at the 0.52 dissimilarity separated genotypes to six main clusters with many subclusters. The local genotypes were distributed to most of all clusters. Genotypes collected from Egypt and King Saud University was grouped together in two clusters, ICARDA’s genotypes in two clusters and two genotypes (H8, local determent genotype and 987–255–95 line) formed a single cluster. The high number of subclusters formed in this study indicated that there is a high genetic variability related to collection sites and it should be utilised in faba bean improvement.

Assessment of genetic diversity among faba bean genotypes using agro-morphological and molecular markers

Forty faba bean (Vicia faba L.) genotypes were evaluated for their agro-morphological performance and molecular diversity under Central Region of Saudi Arabia conditions during 2010–11 and 2011–12 seasons. Field performance results showed that faba genotypes exhibited a significant amount of variation for their agro-morphological studied parameters. Giza40 recorded the tallest genotype (139.5 cm), highest number of seeds per plants (100.8), and the highest seed yield per plant (70.8 g). The best performing genotypes were Giza40, FLIP03-014FB, Gazira1 and Goff1. Genetic variability among genotypes was determined using Sequence Related Amplified Polymorphism (SRAP) and Amplified Fragment Length Polymorphism (AFLP) markers. A total of 183 amplified fragments (alleles) and 1758 polymorphic fragments (bands) in SRAP and 202 alleles and 716 bands in AFLP were obtained using six SRAP and four AFLP primer combinations respectively. Polymorphism information content (PIC) values for AFLP and SRAP markers were higher than 0.8, indicating the existence of a considerable amount of genetic diversity among faba tested genotypes. The UPGMA based clustering of faba genotypes was largely based on origin and/or genetic background. Result of cluster analysis based on SRAP showed weak and not significant correlation while, it was highly significant based on AFLP analysis with agro-morphological characters (r = 0.01, p > 0.54 and r = 0.26, p < 0.004 respectively). Combined SRAP and AFLP markers proved to be significantly useful for genetic diversity assessment at molecular level. They exhibited high discrimination power, and were able to distinguish the faba bean genotypes with high efficiency and accuracy levels.

Comparative nutritional profiles of various faba bean and chickpea genotypes.

Grain legumes are important source of proteins and dietary minerals for humans. In this study, 40 faba bean and 28 chickpea genotypes were evaluated for their nutritional profile. We found that crude proteins ranged from 31.5-37.7% and 19.8-24.9% in faba bean and chickpea genotypes, respectively. Trypsin and chymotrypsin inhibitors varied from 2.24-2.77 and 0.35-0.70 trypsin inhibitory unit (TIU) mg -1 , respectively in faba bean genotypes; whereas, in chickpea genotypes, they ranged from 7.65-8.98 and 9.0-11.9 TIU mg -1 , respectively. Tannins in faba bean ranged from 12.2-16.2 mg 100 g -1 , while in chickpea they ranged from 4.11-4.94 mg g -1 . However, phytic acid ranged from 1.2-1.5 mg 100 g -1 in faba bean, while in chickpea it ranged from 6.10-6.98 mg g -1 . Total phenolic and total flavonoid contents ranged from 5.8-11.3 mg galic acid equivalents (GAE) g -1 and 0.08-0.16 mg quercetin equivalent (QE) g -1 , respectively in faba bean genotypes; whereas, in chickpea genotypes, these ranged from 1.5-2.5 mg GAE g -1 and 0.05-0.18 mg QE g -1 , respectively. In crux, some faba bean and chickpea genotypes could be potential donors for legume genetic improvement and incorporation of such legumes in human diets may improve the nutritional value of diet and can reduce malnutrition.

Faba bean drought responsive gene identification and validation.

This study was carried out to identify drought-responsive genes in a drought tolerant faba bean variety (Hassawi 2) using a suppressive subtraction hybridization approach (SSH). A total of 913 differentially expressed clones were sequenced from a differential cDNA library that resulted in a total of 225 differentially expressed ESTs. The genes of mitochondrial and chloroplast origin were removed, and the remaining 137 EST sequences were submitted to the gene bank EST database (LIBEST_028448). A sequence analysis identified 35 potentially drought stress-related ESTs that regulate ion channels, kinases, and energy production and utilization and transcription factors. Quantitative PCR on Hassawi 2 genotype confirmed that more than 65% of selected drought-responsive genes were drought-related. Among these induced genes, the expression levels of eight highly up-regulated unigenes were further analyzed across 38 selected faba bean genotypes that differ in their drought tolerance levels. These unigenes included ribulose 1,5-bisphosphate carboxylase (rbcL) gene, non-LTR retroelement reverse related, probable cyclic nucleotide-gated ion channel, polyubiquitin, potassium channel, calcium-dependent protein kinase and putative respiratory burst oxidase-like protein C and a novel unigene. The expression patterns of these unigenes were variable across 38 genotypes however, it was found to be very high in tolerant genotype. The up-regulation of these unigenes in majority of tolerant genotypes suggests their possible role in drought tolerance. The identification of possible drought responsive candidate genes in Vicia faba reported here is an important step toward the development of drought-tolerant genotypes that can cope with arid environments.