Bochra Bahri

University of Georgia | UGA · Department of Plant Pathology

Switchgrass (Panicum virgatum L.) is a North American grass species with biofuel potential. Claviceps spp. is known to infect the florets of various grass species, initially characterized by a sticky honeydew exudate and later as sclerotium replacing the seed in the infected ovary (Tanaka et al 2023). Since 2019, from July to October, switchgrass p...

Rhizoctonia large patch (Rhizoctonia solani AG2-2 LP) significantly reduces turfgrass quality, aesthetics, and playability. Synthetic fungicides are commonly used for managing this disease, but they present high costs, potential for fungicide resistance, and environmental concerns. We conducted in vitro assays to test the effectiveness of three bio...

Blackleg, caused by Leptosphaeria maculans , is a major oilseed rape disease present in many traditional growing regions worldwide and is also becoming increasingly important in Tunisia. Cultivation of oilseed rape varieties harbouring major blackleg resistance genes (R‐genes) in an integrated approach represents the most effective means of control...

Dollar spot is a major fungal disease affecting turfgrass worldwide and can quickly destroy turfgrass swards. An assimilating probe-based loop-mediated amplification (LAMP) assay was developed to detect Clarireedia monteithiana and C. jacksonii, the causal agents of dollar spot within the continental US. Five LAMP primers were designed to target th...

Fusarium head blight (FHB) has become a limiting factor in soft red winter wheat production in the southeast US. Recent epidemics have occurred in Georgia, however genetic information on the Fusarium species responsible for FHB is unknown. This study aimed to assess pathogen population structure and genetic diversity, trichothecene profiles, and re...

Abstract The Hessian fly (HF) is an invasive insect that has caused millions of dollars in yield losses to southeastern US wheat farms. Genetic resistance is the most sustainable solution to control HF. However, emerging biotypes are quickly overcoming resistance genes in the southeast; therefore, identifying novel sources of resistance is critica...

The Hessian fly (HF) is an invasive insect that has caused millions of dollars in yield losses to southeastern US wheat farms. Genetic resistance is the most sustainable solution to control HF. However, emerging biotypes are quickly overcoming resistance genes in the southeast; therefore, identifying novel sources of resistance is critical. The res...

Finger millet is a key food security crop widely grown in eastern Africa, India and Nepal. Long considered a ‘poor man’s crop’, finger millet has regained attention over the past decade for its climate resilience and the nutritional qualities of its grain. To bring finger millet breeding into the 21st century, here we present the assembly and annot...

Background Septoria tritici blotch (STB) remains a significant obstacle to durum wheat cultivation on a global scale. This disease remains a challenge for farmers, researchers, and breeders, who are collectively dedicated to reduce its damage and improve wheat resistance. Tunisian durum wheat landraces have been recognized as valuable genetic resso...

Dollar spot caused by Clarireedia spp. (formerly Sclerotinia homoeocarpa) is an economically destructive fungal disease of turfgrass that can significantly compromise turf quality, playability, and aesthetic value. Fungicides are frequently used to manage the disease but are costly and potentially unfavorable to the environment. Repeated use of som...

Blackleg has been observed in oilseed rape in Tunisia since 2017. Morphological observations, pathogenicity tests, and sequencing of the internal transcribed spacer regions for four fungal isolates from affected plants confirmed the presence of Leptosphaeria maculans and Leptosphaeria biglobosa. These results provide the first record of L. maculans...

Dollar spot is one of the most damaging diseases in turfgrass, reducing its quality and playability. Two species, Clarireedia monteithiana and C. jacksonii (formerly Sclerotinia homoeocarpa) have been reported so far in the United States To study the Clarireedia genome, two isolates H2 and H3, sampled from seashore paspalum in Hawaii in 2019 were s...

Species distribution models are widely used to estimate the potential geographic distribution of species habitat. They are also used to predict the impact of climate change on species distributions. In this study, we examined the distribution of Mal Secco disease, an infective disease of citrus caused by the fungus Plenodomus tracheiphilus. To mode...

Recent occurrence in Tunisia of Citrus blast and black pit disease, caused by Pseudomonas syringae pv. syringae (Pss), the few available antibacterial chemicals, and the increasing resistance of Pss to copper sulfate highlighted the need for new antibacterial agents. In vitro analysis of the antagonistic activity of fifty-four native epiphytic bact...

Background Septoria tritici blotch (STB), caused by Zymoseptoria tritici ( Z. tritici ) , is an important biotic threat to durum wheat in the entire Mediterranean Basin. Although most durum wheat cultivars are susceptible to Z. tritici , research in STB resistance in durum wheat has been limited. Results In our study, we have identified resistance...

Septoria tritici blotch (STB) is a major disease problem of wheat worldwide. To optimize the introgression of resistance genes in elite genotypes throughout traditional or molecular breeding programs, a full understanding of the quantitative inheritance of resistance to Zymoseptoria tritici, plant height (PH), and thousand kernel weight (TKW) is ne...

Septoria tritici blotch (STB) caused by Zymoseptoria tritici is the primary biotic stress for durum wheat production in Tunisia. The present study was aimed to decipher the genetic diversity and population structure of Z. tritici bread wheat isolates; in the northern regions of Tunisia this pathogen infected exclusively bread wheat. A total of 162...

Background Tunisia is considered a secondary center of diversification of durum wheat and has a large number of abandoned old local landraces. An accurate investigation and characterization of the morphological and genetic features of these landraces would allow their rehabilitation and utilization in wheat breeding programs. Here, we investigated...

Background: Septoria tritici blotch (STB) has marked durum wheat production worldwide. This fungal disease is until today a challenge for farmers, researchers and breeders all united in the aim of reducing its damage and improving wheat resistance. Tunisian durum wheat landraces were reported to be valuable genetic resources for resistance to bioti...

Background: Septoria tritici blotch (STB) has marked durum wheat production worldwide. This fungal disease is until today a challenge for farmers, researchers and breeders all united in the aim of reducing its damage and improving wheat resistance. Tunisian durum wheat landraces were reported to be valuable genetic resources for resistance to bioti...

Background Septoria tritici blotch (STB), caused by Zymoseptoria tritici (Z. tritici), is an important biotic threat to durum wheat in the entire Mediterranean Basin. Although most durum wheat cultivars are susceptible to Z. tritici, research in STB resistance in durum wheat has been limited. Results In our study, we have identified resistance to...

In southeastern U.S., oat (Avena sativa L.) is predominantly grown as a grain or forage crop due to its exceptional palatability (Buntin et al. 2009). In November 2020, leaf spot symptoms were observed in an oat field (cv. Horizon 720) in Screven County, Georgia (GPS: 32°38'57.6"N 81°31'32.178"W). Lesions were oblong, whitish to gray in color, and...

Dollar spot, caused by the fungal pathogens Clarireedia spp. (formerly Sclerotinia homoeocarpa), is the most common and widely distributed disease of turfgrass worldwide. It can drastically reduce the quality of turfgrass species and impact their aesthetic value and playability. Management of dollar spot typically includes a costly program of multi...

Dollar spot is one of the most destructive diseases in turfgrass. The causal agents belong to the genus Clarireedia, which are known for causing necrotic, sunken spots in turfgrass that coa-lesce into large damaged areas. In low tolerance settings like turfgrass, it is of vital importance to rapidly detect and identify the pathogens. There are a fe...

Stem rust, caused by Puccinia graminis, and crown rust, caused by P. coronata, are common rust diseases on cool-season grasses (Karakkat et al. 2018), for which long-distance spore dispersal was recorded in northern US (Harder and Haber 1992). During the summers of 2019 and 2020, severe infection of stem rust and crown rust was observed on > 60% of...

Soil microorganisms are generally considered sensitive indicators of soil health and fertility. Understanding the role of environmental factors in driving soil microorganisms’ distributions is vital for sustainable crop production, particularly in vulnerable agricultural systems. This study aims to investigate the effect of environmental factors on...

Citrus blast and black pit caused by Pseudomonas syringae pv. syringae (Pss) is the only bacterial disease reported in Tunisian Citrus orchards. The phylogenetic relationship between Pss strains was studied based on multilocus sequence analysis (MLSA), using partial sequences of housekeeping genes rpoD, rpoB, gyrB, cts, and pfk for 14 representativ...

Key message Mapping combined with expression and variant analyses in switchgrass, a crop with complex genetics, identified a cluster of candidate genes for leaf wax in a fast-evolving region of chromosome 7K. Abstract Switchgrass ( Panicum virgatum L.) is a promising warm-season candidate energy crop. It occurs in two ecotypes, upland and lowland,...

Hypericum triquetrifolium Turra is an ecologically, medicinally and economically important species in Tunisia. Thirty-six Hypericum individuals sampled from 6 northern Tunisian locations were investigated for their diversity and relationships using 10 inter-simple sequence repeats (ISSR) markers and 10 morphological features at vegetative stage. Th...

Background: Tunisia is a center of genetic diversity of durum wheat and has a large number of abandoned old local landraces. An accurate investigation and characterization of the morphological and genetic features of these landraces would allow their rehabilitation and use for practical and beneficial purposes. In this context, a collection of 304...

Background: Tunisia is a center of genetic diversity of durum wheat and has a large number of abandoned old local landraces. An accurate investigation and characterization of the morphological and genetic features of these landraces would allow their rehabilitation and use for practical and beneficial purposes. In this context, a collection of 304...

Background: Tunisia is considered a secondary center of diversification of durum wheat and has a large number of abandoned old local landraces. An accurate investigation and characterization of the morphological and genetic features of these landraces would allow their rehabilitation and utilization in wheat breeding programs. Here, we investigated...

Citrus blast and black pit caused by Pseudomonas syringae pv. syringae (Pss) is the only bacterial disease reported in the Tunisian Citrus orchards. The phylogenetic relationship between Pss strains was studied based on Multilocus Sequence Analysis (MLSA), using partial housekeeping genes sequences of rpoD, rpoB, gyrB, cts, and pfk for fourteen rep...

Among the biotic constraints to wheat (Triticum aestivum L.) production, fusarium head blight (FHB), caused by Fusarium graminearum, leaf rust (LR), caused by Puccinia triticina, and stripe rust (SR) caused by Puccinia striiformis are problematic fungal diseases worldwide. Each can significantly reduce grain yield while FHB causes additional food a...

Dollar spot caused by the fungal pathogen Clarireedia spp, is an important disease of all warm and cool season grasses that are grown in the US, including the state of Georgia. Disease symptoms similar to those of dollar spot i.e., white to straw-colored circular lesions on leaf blades and large irregular sunken patches on turf swards, were regular...

Switchgrass (Panicum virgatum), a C4 perennial grass native to North America and developed as a sustainable biofuel feedstock, occurs in two ecotypes, lowland and upland, which vary in their architecture as well as their range of adaptation. In this study, we assessed single nucleotide polymorphism (SNP) variation in 372 switchgrass genotypes for n...

Eremurus species, better known as ‘Foxtail Lily’ or ‘Desert Candle’, are important worldwide in landscaping and the cut-flower industry. One of the centers of highest diversity of the genus Eremurus is Iran, which has seven species. However, little is known about the genetic diversity within the genus Eremurus. With the advent of genotyping-by-sequ...

Yellow rust is the major wheat disease in Central West Asia and North Africa. Severe epidemics have occurred in recent years, with major yield losses in 2010‐2011 in Lebanon and Syria. We conducted an extensive field survey, with a collection of 273 samples of Puccinia striiformis f. sp. tritici, to explore the origin of these epidemics. All sample...

Tunisia is one of the main producers of durum wheat, the most consumed cereal in Tunisia and represents a trademark of several local dishes such as couscous and bulgur. Nonetheless and despite its leading stand in the local consumption and commercial share, a scarcity in Tunisian durum wheat production has long been a major problem obstructing the...

Blue mold rot, caused by Penicillium expansum , is one of the most economically important post-harvest diseases of apple worldwide. The goals of this study were threefold: to evaluate the diversity of P. expansum isolates for mycelial growth, spore production and lesion diameter on apples; to estimate the effects of cold-storage facility conditions...

This is the first report of Rhodococcus spp. causing disease on Iresine herbstii plants, and the first report of pathogenic Rhodococcus spp. in Tunisia.

Anthracnose Citrus disease has been associated with several symptoms worldwide and it is recently compromising Citrus production in the Mediterranean area. Four species complexes are mainly involved: Colletotrichum boninense, C. acutatum, C. gloeosporioides and C. truncatum. In this study, we investigated the genetic diversity of Colletotrichum spp...

Date palm (Phoenix dactylifera), one of the most ancient crops, is grown commercially in >30 countries. Using whole plastome assemblies, phylogenetic analyses revealed that cultivated date palm accessions share the same clade with P. sylvestris, P. pusilla and P. acaulis, which are native to the Indian subcontinent, and P.caespitosa that is native...

Background: Advances in genomic technologies have expanded our ability to accurately and exhaustively detect natural genomic variants that can be applied in crop improvement and to increase our knowledge of plant evolution and adaptation. Switchgrass (Panicum virgatum L.), an allotetraploid (2n = 4× = 36) perennial C4 grass (Poaceae family) native...

Setaria (L.) P. Beauv is a genus of grasses that belongs to the Poaceae (grass) family, subfamily Panicoideae. Two members of the Setaria genus, Setaria italica (foxtail millet) and S. viridis (green foxtail), have been studied extensively over the past few years as model species for C4-photosynthesis and to facilitate genome studies in complex Pan...

Multi-sequence alignment of the Sh1 alleles and transcripts in S. viridis accession A10 and S. italica accessions Yugu1, B100, Ise-3 and Ise-5. Genomic and cDNA sequences are indicated with “genomic” and “cDNA,” respectively, in the sequence name. Intron sequences have a white background, exon sequences have brown (A), yellow (C), green (T), and pu...

Semi-quantitative RT-PCR of qSH1 in leaves and panicles of A10 and B100.

Insertion of (A) MITE 1 and (B) MITE 2 in the 5′UTR of qSH1 was accompanied or followed by rearrangements. The MITE sequence is delineated by “|”. Deletions are in red, insertions in green. [ ] indicates SSR units. Microhomology flanking the deletion is highlighted in yellow.

Alignment of RNA-Seq reads against Sh1 genomic sequence. (A) A10 reads (SRX875196) against Sevir.9G153200 (only the read coverage is shown) and (B) Yugu1 reads (SRX2832831) against Seita.9G154300 (both read coverage and individual read alignments are shown). Exon locations are indicated with red boxes. The MITE location in Seita9G.154300 is shown i...

Multi-sequence alignment at the protein level across different grass species of the qSH1 region carrying the non-synonymous SNP that differentiates S. italica from S. viridis (position 31 in this alignment).

Genotypic and phenotypic data for the B100 × A10 F2:3 and RIL populations.

Presence/absence of MITEs 1 and 2 in qSH1 in S. italica germplasm.

Multi-sequence alignment of the qSH1 alleles in S. viridis accession A10, and S. italica accessions B100 and Yugu1. MITE sequences have green (A), orange (C), blue (T), and red (G) backgrounds. The “ATG” start codon has a white background.

Yellow rust is a devastating wheat disease. Since 2000, Puccinia striiformis f. sp. tritici strains, PstS1/S2 became adapted to high temperature and spread worldwide. By 2011 Warrior strains invaded warm and cold areas of Europe. We questioned whether thermal aptitude promoted the spread of Warrior strains, similar to PstS1/S2. We compared infectio...

The soil organic matter (SOM) appears to play a remarkable role in sustaining four major ecosystem services: resistance to soil erosion, soil water retention, soil fertility for plants, and soil biodiversity.

Lignin is a hydrophobic polymer that provides mechanical strength to plant organs. However, the presence of lignin in plant cell walls reduces the efficiency of ethanol production from lignocellulosic biomass and the digestibility of forage for animal consumption.

Tunisian table grape production has significantly increased since two decades due to vineyards regional expansion and yield improvement. But, since several years, decline symptoms on Vitis vinifera have been recorded in some areas. A study case of a vineyard in Naassen area (near to Tunis) was chosen to investigate the disease origin and the physio...

The importance of the warm‐season grass Paspalum vaginatum Sw. lies in its salt tolerance and its ability to serve as forage, ground cover for erosion control, and turf for sport surfaces in vulnerable areas in the tropics and subtropics. We conducted DNA content measurements using flow cytometry and diversity analyses using 43 simple sequence repe...

Setaria viridis (L.) P. Beauv. and its domesticated form, S. italica (L.) P. Beauv., have been developed over the past few years as model systems for C4 photosynthesis and for the analysis of bioenergy traits. S. viridis is native to Eurasia, but is now a ubiquitous weed. An analysis of the population structure of a set of 232 S. viridis lines, mos...

In order to study the genetic diversity, the phylogeographic pattern and hybridization between six Tunisian Capparis species, 213 accessions of Caper were genotyped with three primer combinations of amplified fragment length polymorphism (AFLP) markers. Out of 750 fragments generated, 636 were polymorphic and 407 of them were restricted to a single...