Fire blight (Erwinia amylovora) disease in Morocco: Current status and action for its management

Fire Blight, caused by Erwinia amylovora, is one of major economic threats to pear and apple growing areas worldwide. In Morocco, this devastating bacterium was first detected in 2006 on pear plantations in Ain Orma district of the Meknes region. Since then, the pathogen was progressively spreading to different regions of pear, apple and quince production, resulting in important losses. As a result, over 2312 Ha of pear, quince and apple orchards were eradicated in 2013. The situation was described as an economic disaster never seen before in the country. Currently, the middle Atlas region, the stronghold of the Moroccan rosaceous production, was entirely affected by this disease. Following the appearance of the bacterium, several approaches including morphological, physiological, biochemical, serological and molecular traits, were undertaken for the early detection and identification of E. amylovora. In this review, we discuss rigorous actions taken by Moroccan authorities to overcome the fire blight outbreak, which includes entire eradication of infected commercial orchards and individual trees. Therefore, the disease incidence rate was reduced, and the infected zone was restricted. In addition, during the last 10 years, studies on bacterium strains diversity and origin were performed using different methods; RFLP, RAPD, rep-PCR, fAFLP, VNTR and biochemical tests. In recent years, with the use of tolerant cultivars, research is oriented to develop an effective and reliable alternative control strategy for fire blight disease using an integrated approach. Keywords: Erwinia amylovora, Morocco, detection, diversity, economic losse

A Current Overview of Two Viroids Prevailing in Citrus Orchards: Citrus Exocortis Viroid and Hop Stunt Viroid

Citrus exocortis viroid (CEVd) and hop stunt viroid (HSVd) are the main viroids circulating in all citrus-growing areas worldwide, and causing two well-known diseases on citrus trees; exocortis and cachexia, respectively. These viroids are small, covalently closed single-stranded RNA, allocated to the Pospiviroidae family. CEVd is the first viroid being described on citrus trees in 1948 in California. It is considered the largest citrus viroid at 371 nucleotides. It causes bark scaling disorder on the rootstock of citrus trees grafted on trifoliate orange and its hybrids and can cause dwarfing of trees grown on these rootstocks. HSVd was first observed in 1945 in Florida. It consists of 299 nucleotides. Stunting, chlorosis, bark gumming, stem pitting, decline, and depressions in the wood are the main symptoms of HSVd in mandarin and its hybrids. The introduction and propagation of infected budwoods are the main causes of viroids spread in citrus orchards. These agents are mechanically sap-transmissible and spread by contaminated tools. Neither seed transmission nor vectors have been reported for both viroids. Root transmission, though possible, would be overshadowed by mechanical transmission. Rapid and sensitive molecular-based detection methods specific to both viroids are available. Both diseases are controlled by using viroids-free budwoods for new plantations, launching budwood certification programs, and establishing a quarantine system for new citrus varieties introduction. The most important achievements in CEVd and HSVd researches are outlined in this chapter. This would help to provide a clearer understanding of the diseases they cause and contribute to the development of better control strategies

ATR-FTIR spectroscopy combined with DNA barcoding and GC-MS to assess the quality and purity of saffron (Crocus Sativus L.)

peer reviewedFourier transform infrared spectra of saffron (Crocus sativus L.) samples were acquired using attenuated total reflectance (ATR-FTIR). The main objective of the study was to determine the chemical composition of 11 samples of saffron collected from different areas in Morocco using the chemometric analysis of ATR-FTIR fingerprints and identifying the adulterated saffron among samples bought from local markets in different countries (Spain, Iran, and Morocco). The the authenticity and the purity of saffron samples was validated through a molecular analysis (DNA barcoding coupled to sequencing) and chromatographic analysis GC-MS. The results of ATR-FTIR showed vibration intensities of six distinct fingerprint regions displaying statistically significant differences. The spectrum of the sample from Timjicht (Taznakht) showed typical bands due to the vibration in 3000-2800 cm-1 (the richest in carbohydrates, lipids, and amino acids) and 1800 to 1725 cm-1 region (the richest in carbonyl and ester groups) and was classified a single subset in samples scatter plot. Then samples from Boulmane (S2), Ain Leuh (S3), Taliouine (S6), and Taznakht (S7-S8) were classified close to each other, which indicates the similarity in their vibration intensities mainly in the region of carbohydrates, lipids, amino acids, and esters. Similarities in terms of proteins and hydroxyl groups were revealed between the samples from El Mers (S11) and Taliouine (S1). Finally, the last subgroup contained samples from Ourika, Azilal and Ain Atia, which showed low composition in all components. Furthermore, to detect adulterated saffron from samples of unknown origin, a comparison of the ATR-FTIR spectra were carried out with spectra of pure saffron and results Journal Pre-proof 2 showed that the peaks at 1706, 1732, and 1225 cm-1 (linked to crocin which are present primarily in saffron) were absent in one sample (SI). Interestingly, the use of another plant species named Arrhenatherum elatius as materiel for saffron adulteration was confirmed by the molecular study (DNA barcoding) and chromatographic analysis GC-M

Viruses of cucurbit crops: current status in the Mediterranean Region

peer reviewedCucurbits are among the most cultivated crops, and the most economically important species are melon (Cucumis melo L.), cucumber (Cucumis sativus L.), watermelon (Citrullus lanatus Thumb.), squash (Cucurbita pepo L.), and pumpkin (Cucurbita spp.). These crops have become important income sources providing export and local consumption commodities in many Mediterranean countries. Increased area of cucurbits has led to the emergence of several viral diseases, which can have impacts on crop production and threaten agricultural sustainability. An overview of the most damaging cucurbit viruses in the Mediterranean area is provided to improve understanding of the diseases they cause and to emphasize effective disease management strategies. An updating of the geographical distribution of these viruses, the symptoms they cause and their means of transmission is also provided. Disease management methods and measures by farmers and phytosanitary authorities to address the virus outbreaks are outlined, including diagnostics, use of tolerant cultivars, and chemical and biological vector control. Mediterranean region farmers have learned many lessons from the damaging pandemics caused by cucurbit viruses, through the extensive published research, and this review provides a basis for managing future outbreaks of newly emerging virus infections