The productivity of durum wheat Triticum turgidum subsp. durum (Desf.) van Slageren is affected by drought and/or high temperatures, challenges to be amplified by climate change. Pre‐breeding using ...wild relatives can supply useful traits for durum wheat improvement to adapt to major abiotic and biotic stresses. Sixty‐seven lines issued from backcrosses of Cham5 and Haurani durum wheat varieties with accessions of Triticum aegilopoides (Link) Bal. ex Koern., T. dicoccoides Koern. ex Schweinf., T. urartu Thumanian ex Gandilyan, and Aegilops speltoides Tausch were evaluated for drought and heat tolerance. The trials were conducted during two seasons (2016−2017 and 2017–2018) at Tessaout, Morocco, under full irrigation (optimal conditions) and rainfed conditions (drought stressed) and at Wed Medani, Sudan, under full irrigation combined with heat stress. The recurrent parents, along with eight best cultivars and elite breeding lines, were used as checks. Drought reduced the grain yield by 62%. Grain yield and drought tolerance index were used to identify lines to be used by breeding programs to enhance drought and heat tolerance. The derivatives lines 142014 (Cham5*3/T. aegilopoides), 142074 (Cham5*3/T. dicoccoides), and 142015 along with the checks Icarachaz and Gidara 2 ranked among the best under heat stress. Under drought stress, the lines 141972 (Haurani*2/T. urartu) and 141973 (Cham5*2/T. dicoccoides) yielded 196 and 142% of their recurrent parents’ yield, respectively. High variation was found for agronomic and phenology traits, with heading time explaining 16% of grain yield under drought, while thousand kernel weight accounted for 18% of the yield under heat. We conclude that gene introgression from wild relatives pays off and can increase wheat resilience to cope with climate change effects.
Durum wheat is the 10th most important crop in the world, and its use traces back to the origin of agriculture. Unfortunately, in the last century only part of the genetic diversity available for ...this species has been captured in modern varieties through breeding. Here, the population structure and genetic diversity shared among elites and landraces collected from 32 countries was investigated. A total of 370 entries were genotyped with Axiom 35K array to identify 8,173 segregating single nucleotide polymorphisms (SNPs). Of these, 500 were selected as highly informative with a PIC value above 0.32 and used to test population structure via DAPC, STRUCTURE, and neighbor joining tree. A total of 10 sub-populations could be identified, six constituted by modern germplasm and four by landraces of different geographical origin. Interestingly, genomic comparison among groups indicated that Middle East and Ethiopia had the lowest level of allelic diversity, while breeding programs and landraces collected outside these regions were the richest in rare alleles. Further, phylogenetic analysis among landraces indicated that Ethiopia might represent a second center of origin of durum wheat, rather than a second domestication site as previously believed. Together, the analyses carried here provide a global picture of the available genetic diversity for this crop and shall guide its targeted use by breeders.
Pollutions associated with mining activities are environmentally challenging worldwide, particularly in Sub Saharan African countries due to extreme climatic conditions, influencing the dispersion of ...metallic pollutants in ecosystems. Mine tailings subjected to acid mine drainage or eolian erosion represent a major source of damages to the environment. Microorganisms play a key role in biogeochemical cycles controlling metals and metalloids fate and behavior in polluted environments. Some microorganisms accelerate the oxidative dissolution of sulfide minerals, leading to the formation of acid mine drainages. In another hand, microorganisms can favor the precipitation of toxic metals and metalloids in solution, contributing to the natural attenuation of polluted waters. These natural capacities can be exploited for the bioremediation of mine impacted sites. Microorganisms also play a key role in phytostabilisation, either indirectly by promoting plant growth or directly through metals and metalloids mobilization or immobilization in soils. Thus, microorganisms are important actors of mining sites remediation. Advances in the field of high throughput sequencing techniques have revolutionized molecular biology and opened a new era in research on microbial ecology, enabling to explore the diversity and activity of microbial communities thriving in polluted environments. In-depth understanding of microbial activity will contribute to improve the mitigation of pollutions. In this work, we review the progress made in using microorganisms to remediate acid mine drainage pollutions, with emphasis on bioremediation case studies in Sub Saharan Africa. The study also highlights the role of microbial communities in the phytoremediation of mine tailings.
The current study aimed to analyze bacterial communities' diversity and abundance in three different deserted areas (Merzouga, Mhamid Elghizlane, and Erg lihoud) located in Moroccan Sahara, as well ...as to investigate osmotolerant microorganisms producing hydrolytic enzymes. The isolates were taxonomically affiliated using 16S rRNA gene sequencing. Four different hydrolase activities (amylase, lipase, cellulase, and protease) and osmotic stress tolerance were evaluated. The phylogenetic analysis of 364 screened isolates belonged to three phyla (Firmicutes 73%, Proteobacteria 26% and Actinobacteria 1%) and 18 different genera, from
. The results detected a high proportion of osmotolerant and enzymes producing bacteria, many isolates can tolerate up to 55 °C (40%, 28%, and 30% in Merzouga, Mhamid Elghizlane, and Erg lihoudi, respectively). Meanwhile, the salinity tolerance reached 12% in some isolates with different proportions in each site, 29% in Merzouga, 24% in Mhamid Elghizlane, and 9% in Erg lihoudi. Furthermore, the enzymatic tests showed the presence of an amylolytic, lipolytic, cellulolytic, proteolytic activities in 20%, 31%, 63% and 72% of total strains, respectively. As a result, the present study is thus a preliminary yet critical step towards identifying the best bacterial candidates for further biotechnological applications.
Abstract
Barley production worldwide is limited by several abiotic and biotic stresses and breeding of highly productive and adapted varieties is key to overcome these challenges. Leaf scald, caused ...by
Rhynchosporium commune
is a major disease of barley that requires the identification of novel sources of resistance. In this study two subsets of genebank accessions were used: one extracted from the Reference set developed within the Generation Challenge Program (GCP) with 191 accessions, and the other with 101 accessions selected using the filtering approach of the Focused Identification of Germplasm Strategy (FIGS). These subsets were evaluated for resistance to scald at the seedling stage under controlled conditions using two Moroccan isolates, and at the adult plant stage in Ethiopia and Morocco. The results showed that both GCP and FIGS subsets were able to identify sources of resistance to leaf scald at both plant growth stages. In addition, the test of independence and goodness of fit showed that FIGS filtering approach was able to capture higher percentages of resistant accessions compared to GCP subset at the seedling stage against two Moroccan scald isolates, and at the adult plant stage against four field populations of Morocco and Ethiopia, with the exception of Holetta nursery 2017. Furthermore, four machine learning models were tuned on training sets to predict scald reactions on the test sets based on diverse metrics (accuracy, specificity, and Kappa). All models efficiently identified resistant accessions with specificities higher than 0.88 but showed different performances between isolates at the seedling and to field populations at the adult plant stage. The findings of our study will help in fine-tuning FIGS approach using machine learning for the selection of best-bet subsets for resistance to scald disease from the large number of genebank accessions.
Drought and desertification are the major environmental constraints facing the Sahelian agro-ecosystems for decades. Assessing genetic diversity of native tree species is critical to assist ...ecosystems restoration efforts. Here we describe genetic diversity and structure of seven Balanites aegyptiaca L. natural populations distributed across the Sahelian-Saharan zone of Mauritania using 16 polymorphic ISSR primers. These generated 505 polymorphic bands. Polymorphism information content (PIC) varied from (0.13-0.29) with an average 0.23, marker index (MI) averaged 7.3 (range 3.3-10.3) and resolving power (RP) ranged from (4.53-14.6) with an average 9.9. The number of observed alleles (Na) ranged from (0.62-1.39), Effective number of alleles (Ne) varied from (1.26-1.37), Shannon's information index (I) ranged from (0.25-0.36). AMOVA analysis showed that 80% of the genetic variation was fined within populations, which is supported by a low level of genetic differentiation between population (GST = 0.21) and an overall estimate of gene flow among populations (Nm = 1.9). The dendrogram based on Jaccard's similarity coefficient and the structure analysis divided the seven populations into two main clusters in which two populations from the Saharan zone were grouped. Our results provide baseline data for genetic conservation programs of this Sahelian neglected crop and with an important econ-ecological role.
Tetraclinis articulata
(Vahl) Masters (Cupressaceae) is a woody tree species indigenous to North Africa. It is also found occasionally in Malta and Spain showing significant adaptability to different ...bioclimatic conditions. Due to its economic and ecologic values, this tree is affected by human and environmental disturbance leading to habitat fragmentation and genetic diversity loss. In this study, we aimed to promote the conservation of
T. articulata
, by measuring the allelic richness of a representative sample of 129 germplasms. Results showed differences in allele distribution. Inter–simple sequence repeat (ISSR) markers and the advanced maximization strategy implemented in PowerCore software were deployed to establish the first core collection of
T. articulata
. A core collection containing 10.07% out of the 129
T. articulata
germplasms was established. The representativeness of the core collection was evaluated and validated by different methods. The genetic diversity parameters or molecular traits (the observed number of alleles (Na), the effective number of alleles (Ne), Shannon’s information index (
I
), and Nei’s expected heterozygosity (He) showed similarities between the core collection and the entire collection averaging at Na = 1.712, Ne = 1.398,
I
= 0.395, and He = 0.253 and Na = 1.970 Ne = 1.363,
I
= 0.382, and He = 0.238, respectively. The analysis of molecular variance indicates that most of the genetic variation in
Articulata
core collections resided within populations (96%), with lesser amounts among populations (4%). Two clusters were identified with STRUCTURE and validated with unweighted pair group method with arithmetic mean dendrogram. The identified collection will be useful for conservation and breeding programs.
Barley is a crop of global significance with multiple uses (feed, food and beverages), but its productivity worldwide is limited by several abiotic and biotic stresses. Crop wild relatives, ...exclusively, Hordeum vulgare ssp. spontaneum and H. bulbosum, are important genetic resources needed to develop new adapted varieties. A total of 117 accessions of H. spontaneum from different origins and 145 lines derived from crosses between barley and H. bulbosum supplied by NordGen were evaluated for field reactions to four major diseases. In addition, a set of 45 lines derived from interspecific crosses with H. spontaneum and H. bulbosum along with 10 checks were evaluated for agronomic traits and yield performance under four different environmental conditions and for quality attributes. The results showed that 37.7%, 71.6%, 15.1%, and 79.5% of H. spontaneum accessions were resistant to moderately resistant to net form net blotch, scald, leaf rust and powdery mildew, respectively, while the respective percentages in case of H. bulbosum derivatives were 31%, 20.4%, 17.9% and 70.6%. Only three accessions of H. spontaneum showed high resistance levels to the four diseases while 23 other accessions and 16 H. bulbosum derived lines showed resistance to a combination of two to four diseases. When H. bulbosum and H. spontaneum derived lines were evaluated under different environments, none of them gave higher grain yield and higher thousand kernel weight than the best checks. However, a few H. bulbosum derived lines showed higher straw yield, and lines combining tall stature, and lodging resistance were identified. Pre‐breeding efforts need to be strengthened further by evaluating more wild Hordeum accessions, their crossing with the best available parents and selection of elite germplasm to be made available to barley breeding programs for the development of new adapted and high yielding varieties.
The argan tree,
(L.) Skeels, is a horticultural forestry species characterized by its endemicity and adaptation to arid and semi-arid zones in the southwest of Morocco. Despite its limited ...geographical distribution, argan tree presents large genetic diversity, suggesting that improvement of argan is possible. This species plays important ecological, and socioeconomic roles in the sustainable development of the country. The integration of arganiculture into Moroccan agricultural policy has been implemented through a sector strategy, which is fully aligned with the conservation and regeneration of argan forest.
is suitable for incorporation into different agroforestry productive systems under agro-fruit-forest model and its domestication will provide a powerful means of socio-economic and environmental management. Here, we provide an overview of the argan tree literature and highlight the specific aspects of argan stands, as agro-forest systems, with the aim of developing an adequate strategy of conservation and domestication of this species. We introduce promising programs and projects for argan plantations and arganiculture, which have been adopted to relieve anthropogenic pressure on the natural argan forest.
Ulvan, carrageenan, alginate and laminarin were tested in olive trees' twigs to elicit phenolic metabolism and control verticillium wilt of olive (VWO) caused by Verticillium dahliae. The elicitation ...effect was determined through phenylalanine ammonia-lyase activity, total polyphenol content and lignin content. VWO was assessed in twigs previously elicited (24 h) and maintained in a solution containing bio-elicitors (2 g/L) and conidial suspension (10
6
conidia/mL). Our results showed stimulation of the phenolic metabolism and the decline of wilt symptoms. Ulvan reduced significantly the area under the disease progress curve for severity to 39.9% and the final incidence to 28.9%. Ulvan and alginate produced significant inhibitory rates on mycelial growth of the fungus in vitro. Seaweed polysaccharides might help to overcome VWO by strengthening the host defense metabolism and restricting the pathogen's growth.
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